The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (2024)

Table of Contents
P001 Allogeneic Stem Cell Transplantation for AML Patients with Runx1 Mutation in First Complete Remission: A Study on behalf of the ALWP of the EBMT Johanna Waidhauser1, Myriam Labopin2,3, Jordi Esteve4, Nicolaus Kröger5, Jan Cornelissen6, Tobias Gedde-Dahl7, Gwendolyn Van Gorkom8, Jürgen Finke9, Montserrat Rovira4, Nicolaas Schaap10, Eefke Petersen11, Dietrich Beelen12, Donald Bunjes13, Christoph Schmid1, Arnon Nagler14, Mohamad Mohty2,3 P002 Graft Failure after Unmanipulated haplo-hsct with pt-cy in Patients with Acute Myeloid Leukemia in Complete Remission, on behalf of the ALWP-EBMT Annalisa Ruggeri1, Myriam Labopin2, Emanuele angelucci3, Didier Blaise4, Fabio Ciceri5, Yener koc6, Jose Luiz Diez-Martin7, Luca castagna8, Benedetto Bruno9, Zafer Gülbas10, Andrea Bacigalupo11, Arnon Nagler12, Mohamad Mohty13 P003 Implications of Novel Risks Scores (AML-DRG and AML-HCT-CR) in Allogeneic CD34+ Selected Graft Transplant Outcomes Rosalia Alonso Trillo1,2, Marta Garcia Recio3, Martina Pennisi2,4, Christina Cho2, Sean M. Devlin2, Josel D. Ruiz2, Molly A. Maloy2, Ana Alarcon Tomas1, Nerea Castillo5, Richard J. Lin2, Ioannis Politikos2, Miriam Sanchez Escamilla6, Michael Scordo2, Gunjan L. Shah2, Juliet N. Barker2, Hugo Castro-Malaspina2, Boglarka Gyurkocza2, Parastoo B. Dahi2, Ann A. Jakubowski2, Esperanza B. Papadopoulos2, Doris M. Ponce2, Craig S. Sauter2, Brian C. Shaffer2, Roni Shouval2, Roni Tamari2, Marcel R. M. van den Brink2, James W. Young2, Sergio A. Giralt2, Miguel Perales2 P004 Downregulation of HLA-DR in Blasts of Patients with Acute Leukaemia Relapsing after Allogeneic Haematopoietic Stem Cell Transplantation Memnon Lysandrou1, Maria Liga1, Eleni Gavriilaki2, Nikolaos Spyridis1, Alexandra Siorenta3, Eleni Kapsali4, Evgenia Verigou1, Vassiliki Douka2, Georgios Vartholomatos4, Ioanna Sakellari2, Achilles Anagnostopoulos2, Alexandros Spyridonidis1 P005 Establishment of a National Stem Cell Transplant Clinical Trials Network: The UK Impact Partnership for Accelerated Cellular Therapies David I Marks1, Shamyla Siddique2, Ronjon Chakraverty3, Aimee Jackson2, Victoria Potter4, Ram Malladi5, Andy Peniket6, Paresh Vyas7, Pamela Kearns2,8, Charles Craddock2,5 P006 A region-wide Retrospective Analysis of Outcome for Patients with Newly Diagnosed Acute Lymphoblastic Leukemia Shuichi Ota1, Akio Shigematsu1, Ryoji Kobayashi2, Takeshi Kondo3, Tomoyuki Endo4, Yutaka Tsutsumi5, Hajime Kobayashi6, Yasutaka Kakinoki7, Satoshi Yamamoto8, Yuichi Konuma9, Takuto Miyagishima10, Tetsuyuki Igarashi11, Takanori Oda12, Hajime Sakai13, Toshimichi Ishihara14, Masahiro Yoshida15, Takahiro Nagashima16, Kazuya Sato17, Yuji Kanisawa18, Yoshihito Haseyama19, Yasuo Hirayama20, Mitsutoshi Kurosawa21 P007 Pre-harvest Higher Donor Foxp3 Mrna and Lower CD4+ T Cell Concentration Predict Increased Risk of all Relapse after Myeloablative Hct with T-replete Bone Marrow Grafts Niels Jacobsen1, Tina Frisch1, Niels Keiding2, Carsten Heilman1, Henrik Sengeløv1, Hans Madsen1, Hanne Marquart1, Mette Andersen1, Claus Christiansen1, Lars Ryder1 P008 Epidemiology, Management and Economic Impact of Acute Myeloid Leukaemia and Myelodysplastic Syndrome in Spain: A Claims Database Analysis Alicia Marsà1, Meritxell Ascanio1, Teresa Briones2, Josep Darbà3 P009 Pre-transplant Bone Marrow Cellularity and Blood Count Recovery are not Associated with Relapse or Survival Risk following Allogeneic Stem Cell Transplant for AML In Cr1 Igor Novitzky Basso1,2, Shiyi Chen1,2, Jeffrey Lipton1,2, Dennis Kim1,2, Auro Viswabandya1,2, Rajat Kumar1,2, Wilson Lam1,2, Arjun Law1,2, Zeyad Al-Shaibani1,2, Armin Gerbitz1,2, Ivan Pasic1,2, Jonas Mattsson1,2, Fotios Michelis1,2 P010 Immunotherapy Salvage for b-precursor Acute Lymphoblastic Leukemia Relapsing after Allogeneic Stem Cell Transplantation: A Retrospective Analysis by the Alwp of the Ebmt Gesine Bug1, Myriam Labopin2, Ali Bazarbachi3, Eolia Brissot4, Stephen Robinson5, Alessandro Rambaldi6, Ben Carpenter7, Riccardo Saccardi8, Nicolaus Kröger9, Michael Potter10, Ibrahim Yakoub-Agha11, Laimonas Griskevicius12, Sebastian Giebel13, Arnon Nagler14, Mohamad Mohty4 P011 Comparison of pre-transplant Comorbidity Indices in Acute Leukemia Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation Zeynep Arzu Yeğin, Asena Dikyar, Lale Aydın Kaynar, Zübeyde Nur Özkurt, Münci Yağcı P012 Salvage use of venetoclax-based Therapy for Relapsed AML Post Allogeneic Hematopoietic Stem Cell Transplant Joselle Cook, Maansi Joshi, Naseema Gangat, Animesh Pardanani, Ayalew Tefferi, Kebede Begna, Michelle Elliot, Aref Al-Kali, Mrinal Patnaik, Mithun V. Shah, William J. Hogan, Mark Litzow, Hassan B. Alkhateeb P013 Factors Predicting the Outcome of Allogeneic Stem Cell Transplantation in ph-negative Acute Lymphoblastic Leukemia Olga Pirogova, Ksenia Afanaseva, Elena Morozova, Sergey Bondarenko, Inna Markova, Ivan Moiseev, Boris Afanasyev P014 Role of Chimerism and flow-cytometric Monitoring of Measurable Residual Disease(MRD) after Allogeneic Hematopoietic Stem Cell Transplantation(Allo-HSCT) in Predicting Relapse in Acute Myeloid Leukemia(AML) Guldane Cengiz Seval, Eliz Bahar Ulas, Selami Kocak Toprak, Sinem Civriz Bozdag, Meltem Kurt Yuksel, Pervin Topcuoglu, Klara Dalva, Onder Arslan, Muhit Ozcan, Taner Demirer, Osman Ilhan, Hamdi Akan, Meral Beksac, Gunhan Gurman P015 Sorafenib Prolonged Maintenance in flt3-mutated AML Post Transplantation Carmine Liberatore1,2, Matteo Giovanni Carrabba1, Federica Ardizzoia1,2, Andrea Assanelli1, Carlo Messina1, Consuelo Corti1, Massimo Bernardi1, Jacopo Peccatori1, Fabio Ciceri1,2, Maria Teresa Lupo Stanghellini1 P016 Pulmonary Complications (PC) after Allogeneic Hematopoietic Stem Cell Transplantation (Allo-HSCT) in Children with high-risk Acute Leukemia (AL) Anastasia Frolova, Olesia Paina, Alisa Volkova, Polina Kozhokar, Zhemal Rakhanova, Lubov Tsvetkova, Kirill Ekushov, Inna Markova, Elena Babenko, Aleksandr Alyanskiy, Ildar Barkhatov, Maria Vladovskaya, Elena Semenova, Ludmila Zubarovskaya, Boris Afanasyev P017 More than two Cycles of Consolidation Therapy pre-transplantation Benefits AML Patients in Cr1 Who Underwent HLA-matched Sibling Allografts: A Multicenter Study Jing Liu1, De-Pei Wu2, Qi-Fa Liu3, Yang Xu4, Fen Huang3, Xiao-Jun Huang1, Yu Wang4 P018 What can Cnv Analysis add to the Routine Genetic Description of AML Cases? Emilia Jaskula1,2, Mariola Sedzimirska2, Monika Mordak-Domagala2, Janusz Lange2, Krzysztof Suchnicki2, Anna Sobczynska-Konefal2, Marta Lemieszewska2, Helena Pakos2, Agnieszka Tarnowska2, Andrzej Lange1,2 P019 Comparison of the Prognostic Ability of the HCT-CI the Modified EBMT and the EBMT-ADT Pre-transplant Risk Scores for Acute Leukemia Eshrak Al-Shaibani1,2, Sunu Cyriac1,2, Shiyi Chen1,2, Jeffrey H. Lipton1,2, Dennis D. Kim1,2, Auro Viswabandya1,2, Rajat Kumar1,2, Wilson Lam1,2, Arjun Law1,2, Zeyad Al-Shaibani1,2, Armin Gerbitz1,2, Ivan Pasic1,2, Jonas Mattsson1,2, Fotios V. Michelis1,2 P020 GO-FLAG Regimen as a Bridge Therapy to Allogeneic Stem Cell Transplantation in Refractory/relapsed AML Patients Bella Ayubova1, Sergey Bondarenko1, Ivan Moiseev1, Olga Uspenskaya2, Elena Karyagina3, Elena Misyurina4, Evgenia Zhelnova4, Alexander Alyanskiy1, Elena Babenko1, Ildar Barkhatov1, Tatyana Gindina1, Alexander Kulagin1, Boris Afanasyev1 P021 The Impact of Allogeneic Transplantation in AML and Mds with Chromosome 3 Abnormalities Maria Rhida Bautista1, Shiyi Chen2, Wilson Lam1, Fotios Michelis1, Dennis Kim1, Jeffrey Lipton1, Auro Viswabandya1, Rajat Kumar1, Ivan Pasic1, Armin Gerbitz1, Jonas Mattson1, Zeyad Al-Shaibani1, Arjun Law1 P022 Allogeneic Hematopoietic Stem Cell Transplantation Versus chemotherapy-alone in the Treatment of Pediatric Acute Myeloid Leukemia Patients with Mixed Lineage Leukemia (Mll) Rearrangements: Single Center Experience Ibtisam AlQahtani, Amal Al-Seraihy, Ali Alahmari, Mouhab Ayas, Khawar Siddiqui, Ibrahim Ghemlas P023 Posttransplantation Bendamustine for GVHD Prophylaxis in Refractory Acute Leukemia Patients Ivan Moiseev, Sergey Bondarenko, Elena Darskaya, Alexandr Alyanskyi, Anastasiya Beynarovich, Evgeniya Borzenkova, Anna Dotcenko, Olga Kudyasheva, Varvara Ovechkina, Olga Pirogova, Valentina Porunova, Tatyana Rudakova, Olesya Smikova, Boris Afanasyev P024 Immediate Allogeneic Hematopoietic Stem Cell Transplantation for NPM1-mutated AML in Molecular Relapse Kerstin Schaefer-Eckart1, Knut Wendelin1, Sabine Dressler1, Johannes Gaertner1, Christian Thiede2 P025 Flat Regimen as Myeloablative Conditioning with Limited Toxicities for Autologous Stem Cell Transplantation in Patients with Acute Myeloid Leukemia: Results in 30 Patients Massimo Bernardi, Carlo Messina, Sara Mastaglio, Francesca Lorentino, Francesca Pavesi, Matteo Giovanni Carrabba, Jacopo Peccatori, Andrea Assanelli, Luca Vago, Bernhard Gentner, Raffaella Milani, Paola Ronchi, Fabio Giglio, Carmine Liberatore, Federico Erbella, Daniela Clerici, Fabio Ciceri P026 Tyrosine Kinase Inhibitor Treatment after Allogeneic Hematopoietic Stem Cell Transplantation for Philadelphia Chromosome‐positive Acute Lymphoblastic Leukemia Yu-Hsiang Chang1,2, Xiu-Wen Liao1, Jia-Hau Liu1,2, Ming Yao2, Bor-Sheng Ko2, Chi-Cheng Li3, Cheng-Hong Tsai2, Shang-Ju Wu2, Hui-Hsuan Huang2, Tai-Chung Huang2, Hsin-An Hou2, Wen-Chien Chou2, Feng-Ming Tien1,2, Yun-Chu Lin2, Meng-Yao Lu2, Kai-Hsin Lin2, Jih-Luh Tang1,4 P027 Outcomes of Allogeneic Transplantation for Cytogenetic intermediate-risk AML According to the Molecular Risk Based on ELN 2017 Risk Stratification System; Single Center Experience in Korea Haerim Chung, Ji Eun Jang, SooJeong Kim, Jin Seok Kim, Yoo Hong Min, June-Won Cheong P028 The Prognostic Significance of Minimal Residual Disease Monitoring by Wt1 Gene Expression in Peripheral Blood Before and after Allogeneic Stem Cell Transplantation in AML Patients Veronika Valkova, Jan Vydra, Marketa Markova, Antonin Vitek, Ela Cerovska, Monika Belickova, Ludmila Novakova, Barbora Cemusova, Mariana Koubova, Petr Cetkovsky P029 Impact of Posttransplant Tyrosine Kinase Inhibitors Administration on Long Term Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in ph-positive Acute Lymphoblastic Leukemia Patients Kseniia Afanaseva, Elena Morozova, Olga Pirogova, Yulia Vlasova, Anna Smirnova, Sergey Bondarenko, Ivan Moiseev, Boris Afanasyev P030 The Influence of anti-thymocyte Globulin(ATG) on the Outcomes of Patients with AML W/wo Measurable Residual Disease(MRD) at the time of Unrelated Donor Transplantation Guldane Cengiz Seval, Ekin Kircali, Mehmet Akif Baltacı, Sinem Civriz Bozdag, Meltem Kurt Yuksel, Pervin Topcuoglu, Klara Dalva, Onder Arslan, Muhit Ozcan, Taner Demirer, Gunhan Gurman, Osman Ilhan, Hamdi Akan, Meral Beksac, Selami Kocak Toprak P031 MLL-AF6 Fusion Gene Positive AML Treated by Allogeneic Hematopoietic Stem Cell Transplantation has Excellent Overall Survival Wei Ma, Xingyu Cao, Wei Zhang, Min Xiong, Jianping Zhang, Yue Lu, Ruijuan Sun, Zhijie Wei, Deyan Liu, Yanli Zhao, Jiarui Zhou P032 Beneficial Outcome of Allogeneic Stem Cell Transplantation for Blastic Plasmacytoid Dendritic Cell Neoplasm Ji Hyun Lee1, Seok Jin Kim2, Won Seog Kim2, Dok Hyun Yoon3, Cheolwon Suh3, Sung-Soo Yoon4, Youngil Koh4, Ja Min Byun5, Hyeon Seok Eom6, Hyewon Lee6, Jong Ho Won7, Ho Sup Lee8, Deok-Hwan Yang9, Ho-Young Yhim10, Ji Yun Lee11, Jae-Cheol Jo3, Yoo Jin Lee3,12 P033 Nduction of Synergistic Apoptosis and Overcoming of Drug Resistance by Cotargeting of BCL-2 and Na/H Exchanger 1 Pathway in Acute Myeloid Leukemia Cells Shin Young Hyun, Eun Jung Na, Ji Eun Jang, Haerim Chung, Soo Jeong Kim, Jin Seok Kim, Yoo Hong Min, June-Won Cheong P034 Gemtuzumab-ozogamicin for Bridging to Transplant in Refractory/relapsed CD33 Positive Acute Leukemia - is it Worthwhile? Michael Stadler, Vanessa Oberstaedt, Elke Dammann, Lothar Hambach, Eva M. Weissinger, Catherina Lueck, Gernot Beutel, Matthias Eder, Arnold Ganser P035 Azacytidine and Donor Lymphocytes Infusions in Relapsed AML after Allogeneic Hsct: Results in 40 Patients Carmine Liberatore, Francesca Lorentino, Matteo Giovanni Carrabba, Carlo Messina, Luca Vago, Sara Mastaglio, Raffaella Greco, Francesca Pavesi, Sarah Marktel, Francesca Farina, Raffaella Milani, Consuelo Corti, Massimo Bernardi, Jacopo Peccatori, Maria Teresa Lupo Stanghellini, Fabio Ciceri P036 The Results of AML Relapse after Allogeneic Transplantation Treatment, Single Centre Approach Evaluation Markéta Šťastná Marková, Veronika Válková, Antonín Vítek, Ludmila Nováková, Barbora Čemusová, Michal Kolar, Jan Vydra, Petr Cetkovský P037 Allogeneic Hematopoietic Stem Cell Transplantation for Relapsed or Refractory Acute Myeloid Leukemia: A Single Center Analysis Paul Deschamps, Claude-Éric Bulabois, Martin Carré, Anne Thiebaut-Bertrand, Jean-Yves Cahn P038 The Optimal Time for Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Acute Myeloid Leukemia Sergey Bondarenko, Ivan Moiseev, Elena Morozova, Olga Pirogova, Elena Darskaya, Anna Smirnova, Nikolai Tsvetkov, Anastasiya Beynarovich, Irina Samorodova, Tatyana Gindina, Elena Babenko, Ildar Barkhatov, Alexander Alyanskiy, Alexander Kulagin, Boris Afanasyev P039 Impact of ABO Mismatch Allogeneic Transplant in Acute Myeloid Leukemia -A Single Centre Experience Fahad Shaikh, Ganapathi Bhat, Suresh Advani, Samir shah, Reetu Jain P040 Donor Source Impacts on Long Term Survival following Reduced Intensity Allogeneic Stem Cell Transplant in AML Patients Aged 60 and Above William Hayhurst, Asterios Giotas, Chloe Anthias, Sandra Easdale, David Taussig, Mike Potter, Mark Ethell, Joy Brennan, Maria Mulligan, Kim Davis, Emma Thistlethwayte, Emma Nicholson P041 Extra-medullary Recurrence of Acute Myeloid Leukemia as Myeloid Sarcoma after Allogeneic Stem Cell Transplantation: A Case Series Jochen Frietsch1, Friederike Hunstig1,2, Sebastian Scholl1, Andreas Hochhaus1, Inken Hilgendorf1 P042 Allogeneic Stem Cell Transplants in Acute Myeloid Leukaemia; A Single Centre Experience Tomas Kupsa1,2, Jan Vanek2, Benjamin Visek1, Miriam Lanska1, Alzbeta Zavrelova1, Ladislav Jebavy1,2, Jakub Radocha1, Jan M Horacek1,2, Pavel Zak1 P043 Allogeneic Hematopoietic Cell Transplantation for Patients with Acute Myeloid Leukemia not Responding to First Induction Therapy Annalisa Natale1, Stefano Angelini1, Mauro Di Ianni1, Gabriele Papalinetti1, Doriana Vaddinelli1, Paolo Di Bartolomeo1, Giuseppe Calabrese2, Stella Santarone1 P044 Salvage Allogeneic Hematopoietic Stem Cell Transplantation for Severe Aplastic Anemia Patients with Refractory Active Infection: A Prospective Multicenter Clinical Study in China Xia Qin1, Xiangfeng Tang2, Yiping Zhu3, Rongmu Luo4, Ting Yang5, Zimin Sun6, Shaoyan Hu7, Yuan Sun8, Shunqing Wang9, Weiping Zhang10, Xianmin Song11, Jiong Hu12, Ke Huang13, Jing Chen1 P045 Incidence and Management of Aplastic Anemia in Spain (IMAS). An Ambispective Study of Biodonostia / Pethema Carlos Vallejo1, Ana Rosell2, Blanca Xicoy3, Carmen García4, Carmen Albo5, Marta Polo6, Isidro Jarque7 P046 Allogeneic Stem Cell Transplantation from Alternative Donors for Children with Aplastic Anemia Atsushi Narita, Hideki Muramatsu, Masayuki Imaya, Ayako Yamamori, Taro Yoshida, Manabu Wakamatsu, Shunsuke Miwata, Koutaro Narita, Hironobu Kitazawa, Rieko Taniguchi, Motoharu Hamada, Daisuke Ichikawa, Eri Nishikawa, Nozomu Kawashima, Yusuke Okuno, Nobuhiro Nishio, Seiji Kojima, Yoshiyuki Takahashi P047 Outcome of Pediatric Acquired Aplastic Anemia: Single Center Experience Elaf Al nasser, Ibraheem Abosoudah, Naif Aljohani, Hassan Altrabolsi, Ali Alharbi, Mohamed Bayoumy P048 Impact of CD34+-Stem Cell Boost on Outcome and Hematological Reconstitution in Patients with Severe Aplastic Anemia after Allogeneic Stem Cell Transplantation - A Retrospective Study Rashit Bogdanov, Mareike Gocht, Amin Turki, Markus Ditschkowski, Dietrich W. Beelen P049 Hematopoietic Stem Cell Transplant in Adults with Acquired Severe Aplastic Anemia Gilbert Wilfred, Sen Mui Tan, Tee-Chuan Ong, SH. Shahnaz Syed Abd Kadir, Kim Wah Ho, Boon Liaw Kian, Jameela Sathar P050 Hematopoetic Stem Cell Transplant in Fanconi Anemia using Matched Related and Haploidentical Donors- A Single Centre Experience Ajeitha Loganathan, Pooja Mallya, Prathip Kumar, Shobha Badiger, K S Nataraj, Sharat Damodar, P K Vasundhara, Arun Danewa, Mohammed Salmaan, Mohana Reddy, Sunil Bhat P051 Hematopoietic Stem Cell Transplantation for Pediatric Severe Aplastic Anemia: Results of a Single Center Gulen Tuysuz Kintrup, Hilal Akbas, Funda Tayfun Kupesiz, Ayse Nur Akinel, Cigdem Sivrice, Serife Kaya, Elif Guler, Alphan Kupesiz P052 Immunosupressive Therapy in Peadiatric Aplastic Anemia, Single Centre Experience Wafaa Ezzat Ibrahim mohamed Abou Sayed Ahmed, Safa Matboly P053 Cyclosporine, Danazol and Romiplostim in Severe Aplastic Anemia in Prettansplant Period: Retrospective Analysis of Five Cases Nilesh Wasekar, Girish Badarkhe, Sudarshan Pandit, Raj Nagarkar P054 The long-term Safety and Efficacy of Autologous Haematopoietic Stem Cell Transplantation for relapsing-remitting Multiple Sclerosis Indirectly Compared to Alemtuzumab: A Systematic Review Owain Greaves1, Amit Patel1,2 P055 Reconstitution of Natural or vaccination-driven Immunity after aHSCT in Multiple Sclerosis Chiara Innocenti, Elio Ingenito, Maria Pia Amato, Alessandro Barilaro, Gaetano Bianchini, Teresa Capobianco, Maria Antonia Calia, Romina Ceschini, Arianna Fani, Marta Giannini, Antonella Gozzini, Stefano Guidi, Alice Mariottini, Luca Massacesi, Francesca Materozzi, Chiara Nozzoli, Anna Maria Repice, Gian Maria Rossolini, Serena Urbani, Riccardo Saccardi P056 High-dose Immunodepletion with Autologous Stem Cell Rescue for Treatment of Aggressive Multiple Sclerosis Antonia Mueller, Ilijas Jelcic, Panos Stathopoulos, Nathan Wolfensberger, Katharina Ritter, Urs Schanz, Roland Martin P057 Hematopoietic Stem Cell Transplantation does not Change the Expression of Endothelial Markers in Skin Biopsies of Systemic Sclerosis Patients Maynara Santana, Djulio Zanin, Deisy Silva, Marianna Vasconcelos, Daniela Moraes, Juliana Dias, Vanessa Leopoldo, Marília Oliveria, Álvaro Henrique-Neto, Kelen Farias, Leandra Ramalho, Maria Carolina Oliveira P058 Autologous Stem Cell Transplantation for Non Hematological Diseases. The Dutch Experience of MS Patients going Abroad Ellen P.A. Kramer1, Bram Platel2, Frederike J.A.E Ambagtsheer3, Gerald G.J.D Hengstman4, Otto O Visser5 P059 Analysis of Cost and Charges for non-myeloablative Hematopoietic Stem Cell Transplantation for Relapsing Remitting Multiple Sclerosis in the United States Richard Burt, Kathleen Quigley, Indira Arnautovic, Xiaoqiang Han P060 Autologous Stem Cell Transplantation in Behçet´s Disease: A Retrospective Study Mathieu Puyade1,2,3, Amit Patel4, Yeong Ler Lim5, Norbert Blank6, Manuela Badoglio7, Francesca Gualandi8, David Ma9,10,11, Natalia Maximova12, Tobias Alexander13, John Snowden14 P061 Safety and Tolerability of Autologous Hematopoietic Stem Cell Transplant in Multiple Sclerosis: A Single Center Experience Pawan Kumar Singh, Isha Gambhir, Ragesh Radhakrishnan Nair, Rohan Halder, Zahier Ahmad Shekib, Manish Mahajan, Sumit Singh P062 Outcome of Autologous Hematopoietic Stem Cell Transplantation for Refractory Takayasu Arteritis, A Retrospective Survey from the Autoimmune Diseases Working Party (ADWP) of the Ebmt Charlotte Laurent1, Zora Marjanovic2, Laure Ricard2, Joerg Henes3, Remy Dulery2, Manuela Badoglio2, Dominique Farge4, John Snowden5, Dania Moraes6, Juliana Dias6, Mohamad Mohty2, Michael Soussan7, Renate Arnold8, Olivier Fain1, Tobias Alexander8, Maria Carolina Oliveira6, Arsene Mekinian2 P063 The use of Autologous Haemopoetic Stem Cell Transplantation (aHSCT) in Multiple Sclerosis after Alemtuzumab Treatment Failure: A Case Series Simon Bell1, Helen Jessop2, Andrew Chantry2, Basil Sharrack1,2, John Snowden2 P064 Autologous Hematopoietic Stem Cell Transplantation for Treatment of Systemic Sclerosis, an Option for Refractory Patients Claudia Sossa1,2, Javier Figueroa3, Juan Manuel Herrera4, Angela M Peña1, Luis A Salazar1, Manuel Rosales1, Enrique Pedraza3, Elena Mora3, Xueyi Chen2, Maria Luna-Gonzalez2, Jose Patricio Lopez-Lopez1 P065 A Pilot Feasibility Study of non-myeloablative Allogeneic Hematopoietic Stem Cell Transplantation for Refractory Crohn Disease Richard Burt, Kathleen Quigley, Indira Arnautovic, Xiaoqiang Han P066 National Implementation of the use of Tisagenlecleucel in Paediatric and Young Adult Patients with Acute Lymphoblastic Leukaemia (ALL) in National Health Service England (NHSE) Caroline Louise Furness1,2, Rachael Hough3, Michelle Cummins4, Gillian Murphy5, Sara Ghorashian6, Persis Amrolia6, Claire Roddie3, Maeve O’Reilly3, Robert Wynn7, Denise Bonney7, David Marks4, Sridhar Chaganti8, Geoff Shenton9, Anna Castleton10, Eleni Tholouli11, Deborah Yallop12, Peter Clark13, John Snowden14 P067 Real-world Clinical Features of Neurotoxicity Complicating CD19-targeted Chimeric Antigen Receptor (CAR) t-cell Therapy for High Grade Lymphoma and Management Including the off-label use of Anakinra Shafqat Inam, Sean Apap Mangion, Victoria Potter, Reuben Benjamin, Andrea Kuhnl, Robert Hadden, Robin Sanderson P068 P069 P070 Association of axi-cel CAR-T Cell Concentration with Treatment Response and Side Effects and Impact of Dexamethasone Treatment on Kinetics Francis Ayuk1, Anita Badbaran1, Carolina Berger1, Tanja Sonntag1, Kritoffer Riecken1, Maria Geffken1, Dominic Wichmann1, Nicolaus Kröger1, Boris Fehse1 P071 Nivolumab as Salvage Therapy in Patients who Failed to Achieve Complete Remission after anti-CD19 CAR T-cell Therapy for DLBCL Nicolas Gazeau1, David Beauvais1, Salomon Manier1, Marie De Charette de la Contrie1, Micha Srour1, Pauline Varlet1,3, Myriam Labalette1,2, Franck Morschhauser1, Ibrahim Yakoub-Agha1,2 P072 Surveillance of Minimal Residual Disease (MRD) in Diffuse Large B Cell Lymphoma (DLBCL) by Circulating Tumor Dna (CTDNA) Profiling after Chimeric Antigen Receptor T (CAR-T) Houli Zhao1,2,3, Yongxian Hu1,2,3, Wei Ding1, Arnon Nagler4, He Huang1,2,3 P073 A digital-pcr Assay for Precise in-vivo Quantification of Adoptively Transferred CD19-car T Cells after Treatment with Axicabtagene Ciloleucel (AXI-CEL) Boris Fehse, Anita Badbaran, Carolina Berger, Tanja Sonntag, Kristoffer Riecken, Maria Geffken, Nicolaus Kröger, Francis A. Ayuk P074 P075 Axicabtagene Ciloleucel CD19 CAR T-Cells for Relapsed/refractory Large b-cell Lymphoma: real-world Outcomes, Toxicity and Predictors of Response from a Prospective UK Cohort Robin Sanderson, Reuben Benjamin, Piers Patten, Victoria Potter, Deborah Yallup, Kirsty Cuthill, Orla Stewart, Tony Pagliuca, Pramila Krishnamurphy, Shafqat Inam, Mili Shah, Shu Wong, Catherine Hockings, Victoria Metaxa, Andrea Kuhnl P076 P077 Sinusoidal Obstruction Syndrome in Patients with Relapsed/Refractory (R/R) b-cell Acute Lymphoblastic Leukemia (B-all) Treated with ari-0001 Cells Valentín Ortiz-Maldonado1, Anna Alonso-Saladrigues2, Miguel Caballero-Baños3, Maria Castella3, Anna Boronat3, Enric García-Rey4, Tycho Baumann1, Marina Díaz-Beyá1, Montserrat Torrebadell2, Anna Faura2, Albert Català2, Federico Ramos2, Alicia Palomino1, Marta Gómez-Hernando1, Carlos Jiménez-Vicente1, Joan Cid1, Miquel Lozano1, Cristina Llanos2, Adrián Téllez1, Sara Fernández1, Pedro Castro1, Iolanda Jordán2, Jordi Esteve1, Josep Maria Canals5, Esteve Trias4, Jordi Yagüe1, Maria Suárez-Lledó1, Montserrat Rovira1, Alvaro Urbano-Izpizua1, Manel Juan3, Susana Rives2, Julio Delgado1 P078 Humoral Immune Response in Patients with CD19-positive Relapsed/refractory B-cell Malignancies Recruited into the CART19-be-01 Clinical Trial, an Academic CAR19 Nela Klein-González1, E. Azucena González-Navarro1, Ariadna Bartoló-Ibars1, Valentín Ortiz-Maldonado1, Montserrat Torrebadell2, Maria Castellà1,3,4, Daniel Benítez1, Miguel Caballero-Baños1, Raquel Cabezón1, Marta Español-Rego1, Tycho Baumann1, Eva Giné1, Pedro Castro1,3,5, Jordi Esteve2,3,5, Jordi Yagüe1,3,5, Susana Rives2, Álvaro Urbano-Ispizua1,3,5, Julio Delgado1,3, Manel Juan1,3 P079 Real-world Data from Kings College Hospital: Infection Complications Post CAR-T Treatment in high-grade B Cell non-hodgkin Lymphoma Shu Min Wong, Mili Shah, Shafqat Inam, Andrea Kuhnl, Robin Sanderson P080 Senescent/exhausted Phenotype of CD19-targeted CAR-T Cells and Immunoregulatory Environment Correlate with Reduced Response to car-t Cell Therapy in Relapsed/Refractory B Cell Malignancies Katia Beider, Michal J. Besser, Jacob Schachter, Ania Hava Grushchenko-Polaq, Valeria Voevoda-Dimenshtein, Maayan Ulman, Olga Ostrovsky, Elad Jacoby, Avichai Shimoni, Abraham Avigdor, Arnon Nagler P081 Characterisation of Early and Late Cytopenias in Lymphoma Patients following Treatment with anti-CD19 CAR-T Therapy Catherine Hockings, Andrea Kuhnl, Shu Wong, Mili Shah, Shafqat Inam, Piers Patten, Kirsty Cuthill, Tony Pagliuca, Deborah Yallop, Reuben Benjamin, Victoria Potter, Robin Sanderson P082 Impact of Ethnicity in R/R DLBCL and B-cell all Patients Treated with Tisagenlecleucel Ahmed Abdelhady1, Hidefumi Hiramatsu2, Takanori Teshima3, Koji Izutsu4, Koji Kato5, Satoshi Saida6, Tatsuya Kamitori2, Keiji Tasaka2, Itaru Kato2, Katsutsugu Umeda2, Souichi Adachi7, Karen Thudium8, Edward Waldron8, Alessandra Forcina9, Andrea Chassot Agostinho8, Stephan Grupp10,11, Richard T. Maziarz12 P083 Impact of different Chemotherapy Regimens and Duration of DLBCL on Lymphopheresis and car-t T-cell Immunophenotyping David Hagin, Tal Freund, Liav Sela, Rinat Eshel, Odelia Amit, Yael Bar-On, Irit Avivi, Ron Ram P084 Chimeric Antigen Receptor (CAR) T Cell Therapy Followed by Hematopoietic Stem Cell Transplantation May Improve Progression free Survival in Patients with Relapse/Refractory B-cell Non-hodgkin Lymphoma Haiwen Huang, Shuo Liu, Qian Zhu, Yishan Duan, Depei Wu P085 Challenges in providing good Leukapheresis Products for the Production of Car T Cells for Patients with Relapsed/Refractory NHL or ALL Felix Korell1, Sascha Laier2, Sandra Sauer1, Sonia Jaramillo-Segura1, Elisabeth Lasitschka1, Kaya Veelken1, Hannah Hennemann1, Marie-Luisa Schubert1, Tim Sauer1, Petra Pavel2, Carsten Müller-Tidow1, Peter Dreger1, Michael Schmitt1, Anita Schmitt1 P086 NKG2D Car T Cells are not affected by Soluble NKG2D Ligands Adrián Fernández1, Lucía Fernández1, Isabel Mirones2, Adela Escudero2,3, Leila Cardoso2,3, Gloria Esteso4, Raquel De Paz2, Joaquín Martínez-López5, Mar Valés4, Antonio Pérez-Martínez2,6 P087 Emerging Cytokine Release Syndrome is associated with Reduction of CD4+CD25high127dim T Regulatory Cells in Patients after Car T Cell Therapy Christian R Schultze-Florey, Victoria Panagiota, Ivan Odak, Sultan Bektas, Tabea C Froehlich, Aleksandra Gladysz, Zhixiong Li, Gernot Beutel, Matthias Eder, Immo Prinz, Reinhold Foerster, Arnold Ganser, Christian Koenecke P088 Excellent Proliferation and Persistence of Allogeneic CAR-T Cells Despite Immunosuppression with Cyclosporine A Francis Ayuk, Boris Fehse, Dietlinde Janson, Carolina Berger, Kristoffer Riecken, Nicolaus Kröger P089 A French Biobanking Network to Create a Unique Collection of Samples of Patients Treated with car-t Cells Emilie Robert1, Claire Fontenille1, Plotine Crochet1, Régis Peffault de Latour2, Jean-Hugues Dalle3, Boris Calmels4, Thierry Fest5, Loïc Ysebaert6, Catherine Thieblemont7, Cristina Castilla-Llorente8, Franck Morschhauser9, Steven Legouill10, Corinne Haioun11, Emmanuel Bachy12, Guillaume Cartron13, Roch Houot14 P090 CAR T Cell Therapy Directed against CD19 in Patients with B-cell Lymphoma after an Allogeneic Hematopoietic Stem Cell Transplantation (AlloHCT) is Feasible and Safe Maria-Luisa Schubert1, Sascha Dietrich1, Anita Schmitt1, Petra Pavel2, Alexander Kunz1, Andrea Bondong1, Mandy Wegner1, Peter Stadtherr1, Susanne Jung3, Stephan Stilgenbauer4, Anthony Ho1, Carsten Müller-Tidow1, Michael Schmitt1, Peter Dreger1 P091 Lymphocyte Collection for Generation of CAR T-cells in Pediatric Patients: A Single Center Experience Giovanna Del Principe1, Giovanna Leone1, Annalisa Ruggeri1, Simone Biagini1, Elia Girolami1, Stefania Lazzaro1, Antonella Meschini1, Francesca Del Bufalo1, Manuel Broglia1, David Malaspina1, Katia Feri1, Federica Galaverna1, Pietro Merli1, Valentina Bertaina1, Mattia Algeri1, Mauro Montanari1, Andrea Onetti Muda1,2, Giuseppina Li Pira1, Franco Locatelli1,3 P092 Baseline Hypoalbuminemia does not appear to be an Adverse Prognostic Factor in Patients with Relapse/Refractory B-cell Lymphomas Treated with Axicabtagene Ciloleucel (Axi-cel) Megan Melody1, Sangeetha Gandhi2, Zaid Abdel Rahman1, Paula Lengerke Diaz3, Nicole Gannon1, Allison Rosenthal3, Taun Truong2, Mattia Novo2,4, Eva Brandes2, Gina Lange2, Breana Etsby2, Patrick Johnston2, Steve Ansell2, N. Nora Bennani2, Jonas Paludo2, Jose Villasboas Bisneto2, Ernesto Ayala1, Han W. Tun1, Hemant Murthy1, Vivek Roy1, James Foran1, Januario Castro3, Yi Lin2, Mohamed Kharfan-Dabaja1 P093 Factors Predicting CD3+ Collection for the Production of Chimeric Antigen Receptor (CAR) T Cells Silvia Monsalvo, Gonzalo Balsera, Gillen Oarbeascoa, Ana Perez-Corral, Mariana Bastos, Nieves Dorado, Rebeca Bailen, Ariana Ortuzar, Maria Reyes Martin, Maria Consuelo Vega, Carmen Granado, Carmen Falero, Nuria Ruano, Cristina Muñoz, Mi Kwon, Jose Luis Diez-Martin, Javier Anguita P094 Cytopenias after Tisagenlecleucel in Paediatric/young Adult Patients with Refractory/relapse b-cell Acute Lymphoblastic Leukaemia (R/R B-all): A real-life Single-centre Experience Ignacio Gómez-Centurión1, Saskia Burridge2, Juliana Silva2, Arina Lazareva2, María Gabelli2, Oana Mirci-Danicar2, Giovanna Lucchini2, Robert Chiesa2, Kanchan Rao2, Sujith Samarasinghe2, Paul Veys2, Ajay Vora2, Persis Amrolia2, Sara Ghorashian2 P095 The risk of Hepatitis B Reactivation is controllable in B-cell Malignancies Patients with Concomitant Hepatitis B Virus Infection after Chimeric Antigen Receptor T Cell Therapy Fang Ni1,2, Yongxian Hu1, Alex Hong Chang3, He Huang1 P096 Cumulative Rituximab Exposure Prior to Axicabtagene Ciloleucel is not associated with Persistent Leukopenia and Thrombocytopenia at Day +90 Post Infusion Madiha Iqbal1, Sangeetha Gandhi2, Abdullah Alselah2, Muhamad Alhaj Moustafa1, Ernesto Ayala1, Hemant Murthy1, Allison Rosenthal3, Jilan Kubusek2, Justin Haynes2, Tuan Troung2, Patrick Johnston2, Stephen Ansell2, Nora Bennani2, Jonas Paludo2, Jose Villasboas Bisneto4, Breana Estby2, Eva Brandes2, Gina Lange2, Januario Castro3, Yi Lin2, Mohamed Kharfan-Dabaja1 P097 Comprehensive Immune Cell Monitoring Reveals an Altered Lymphocyte Subset Phenotype in Patients not Responding to Tisagenlecleucel One Month Post Infusion Christian R Schultze-Florey, Victoria Panagiota, Ivan Odak, Sultan Bektas, Tabea C Froehlich, Aleksandra Gladysz, Zhixiong Li, Gernot Beutel, Matthias Eder, Immo Prinz, Reinhold Foerster, Arnold Ganser, Christian Koenecke P098 Neurotoxicity associated with CAR T Cell Therapy: Neurological Management and work-up of 11 Adult Patients Nora Moehn, Viktoria Bonda, Mike P. Wattjes, Victoria Panagiota, Sascha David, Gernot Beutel, Matthias Eder, Martin Stangel, Arnold Ganser, Christian Koenecke, Thomas Skripuletz P099 Nutritional Assessment of Patients undergoing CD19-targeted CAR-T Therapy for Non-hodgkin’s Lymphoma and the Short Term Effect of Treatment on Nutritional Status Katie Ahern, Shafqat Inam, Katie Walker, Orla Stewart, Victoria Potter, Piers Patten, Andrea Kuhnl, Deborah Yallop, Reuben Benjamin, Robin Sanderson P100 Effectiveness of Autologous Leukapheresis Collections for CAR T-cell Manufacturing in Patients with B-cell Malignancies Udo Holtick, Anja Jühling, Philipp Gödel, Hyatt Balke-Want, Nadine Kutsch, Özlem Aylikci, Linda Wilhelm, Hanna Birkholz, Christof Scheid, Peter Borchmann P101 Definition and Implementation of Clinical and Quality Endpoints in Centers Administering a Commercial CAR-T Product Ron Ram, Ronit Gold, Odelia Amit, Yael Bar-On, Rinat Eshel, Chava Perry, Nadav Sarid, Yair Herishanu, Noam Benyamini, Irit Avivi P102 CAR-T in Breast and other extra-medullary Relapsed/refractory All Francesco Paolo Tambaro1,2, Sajad Khazal2, Dristhi Ragoonanan2, Priti Tewari2, Demetrios Petropolous2, Jeffrey A Miller2, William G Wierda2, Richard E Champlin2, Kris M Mahadeo2 P103 Predicting CAR T-cell Infusion after Successful Manufacturing: real-world Data Georg-Nikolaus Franke, Eberhard Schleyer, Konstantin Weibl, Hansjakob Fries, Sophia Michel, Rosmarie Pointner, Dominic Brauer, Sandra Otto, Uwe Platzbecker, Vladan Vucinic P104 Evaluation of the Interest of a Drug Reconciliation Activity in Patients Treated with Car T-cells: A Descriptive Study Flore Durieux1, Nicolas Simon1,2, Héloïse Henry1,2, Benjamin Podvin1, Marc Ducatel1, Amandine Legrain1, Valentin Douilly1, David Beauvais1, Bertrand Décaudin1,2, Ibrahim Yakoub-Agha1,3, Pascal Odou1,2 P105 Breaking PD-l1-mediated Resistance in anti-CD19 and anti-CD22 Car T Cells with PD-1/CD28 Fusion Receptors Franziska Blaeschke1, Antonia Apfelbeck1, Dana Stenger1,2, Jasmin Mahdawi1, Mareike Lepenies1, Felicitas Rataj3, Semjon Willier1, Theresa Kaeuferle1, Thomas G. P. Gruenewald2,4, Robbie G. Majzner5, Dirk H. Busch6,8, Sebastian Kobold3, Tobias Feuchtinger1,2,7 P106 Allogeneic Chimeric Antigen receptor-invariant Natural Killer T Cells Exert Both Direct and Indirect Antitumor Effects through Host Cd8 T Cell cross-priming Federico Simonetta1,2, Toshihito Hirai1, Juliane K. Lohmeyer1, Kristina Maas-Bauer1, Maite Alvarez1, Arielle S. Wenokur1, Jeanette Baker1, Amin Aalipour1, Samuel Haile3, Crystal L. Mackall3, Robert S. Negrin1 P107 NKG2D Chimeric Antigen receptor-expressing Lymphocytes Target Acute Myeloid Leukemia Cells Alejandra Leivas1, Laura Córdoba1, Antonio Valeri1, Mari Liz Paciello2, Paula Rio3, Daniel Primo4, Joan Ballesteros4, Lucía Fernández5, Antonio Pérez-Martínez6, Dean A. Lee7, Daniel J. Powell Jr.8, Joaquin Martinez-Lopez1 P108 Clinical-grade Manufacturing of ROR1 CAR T-cells using a Novel virus-free Protocol Katrin Mestermann1, Marie Eichler2, Markus Machwirth1, Kati Kebbel2, Ulrike Köhl2, Hermann Einsele1, Claudia Müller2, Jörg Lehmann2, Tamás Raskó3, Felix Lundberg3, Zsuzsanna Izsvák3, Gerno Schmiedeknecht2, Michael Hudecek1 P109 Lentivirally and Alpharetrovirally Engineered CD19-specific Chimeric Antigen Receptor Natural Killer Cells are Highly Cytotoxic against Acute Lymphoblastic Leukemia Tobias Bexte1,2,3, Stephan Müller1,2,3, Veronika Gebel1,2, Franziska Kalensee1,2, Eva Stolzenberg1, Jessica Hartmann4, Ulrike Koehl5,6,7, Axel Schambach8,9, Wels Winfried S.3,10,11, Ute Modlich12, Evelyn Ullrich1,2,3 P110 Novel Strategies to Enhance the safety of CAR T-cell Immunotherapy: The Imsavar Project Miriam Alb1, Jonathan Moggs2, Lars Wallstabe1, Benedikte Hatz1, Hermann Einsele1, Peter Loskill3, Andries van der Meer4, Scott Wagers5, Ulrike Köhl6, Michael Hudecek1 P111 Adult Peripheral Blood and Umbilical Cord Blood NK Cells Are Good Sources for Effective Car Therapy Against CD19 Positive Leukemic Cells Lara Herrera1,2, Silvia Santos1,2, Miguel Ángel Vesga1,2, Juan Anguita3,4, Itziar Martin-Ruiz3, Tomás Carrascosa2,5, Manel Juan6, Cristina Eguizabal1,2 P112 Tyrosine Kinase Inhibitor Followed by Cart Therapy for the Treatment of Relapsed Philadelphia chromosome-positive B-cell Acute Lymphoblastic Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation YUEHUI LIN, Biping Deng, Zhichao Yin, Lihong An, Defeng Zhao, DAN LIU P113 P114 Adoptive Immunotherapy of Refractory Viral Infections after Allogeneic HSCT: An Academic Network Framing the use of an Atmp under Hospital Exemption Yingying WANG1,2, Marcelo DE CARVALHO1,2, Typhaine PIERRE1, Mélanie GAUTHIER1,2, Véronique DECOT1,2, Laurence CLEMENT3,4, Cécile POCHON1,2,4, Karin BILGER4,5, Jérôme LARGHERO4,6, Hélène ROUARD4,7, Anne FIALAIRE LEGENDRE4,8, Nadine PETITPAIN1,4, Jean Hugues DALLE4,9, Danièle BENSOUSSAN1,2,4 P115 How to Benefit from Exhaustion: patient-derived Inhibited T Cells as a Novel Source of tumor-reactive T Cell Clones Francesco Manfredi1, Lorena Stasi1, Danilo Abbati1, Sara Mastaglio2, Fabio Ciceri2, Eliana Ruggiero1, Chiara Bonini1,2 P116 Efficient Crispr/Cas9-mediated Inactivation of the Glucocorticoid Receptor for antigen-specific T-cell Immunotherapy Maria Alvanou1,2, Anastasios Kouimtzidis1,3, Kyriakos Koukoulias1,3, Chrysoula Pantazi1,3, Nikoletta Psatha4, Giorgios Tsiolas5, Alexandros Spyridonidis2, Kostas Stamatopoulos5, Antonios Makris5, Achilles Anagnostopoulos1, Evangelia Yannaki1, Anastasia Papadopoulou1 P117 Comparison of Outcome post-second Allogeneic Hematopoietic Cell Transplantation Versus Donor Lymphocyte Infusion in Allogeneic Hematopoietic Cell Transplant Patients Eshrak Al-Shaibani1,2, Jeffrey H. Lipton1,2, Dennis D. Kim1,2, Auro Viswabandya1,2, Rajat Kumar1,2, Wilson Lam1,2, Arjun Law1,2, Zeyad Al-Shaibani1,2, Armin Gerbitz1,2, Ivan Pasic1,2, Jonas Mattsson1,2, Fotios V. Michelis1,2 P118 Automated Application for Depletion of Tcrab+, CD19+ and CD45RA+ Cells from Apheresis Products using the Clinimacs Prodigy® Julia Dzionek1, Carina Thießen1, Felix Hebbeker1, Stephanie Soltenborn1, Joanna Justyna Stenzel1, Burgund Kauling1, René Meißner1, Nikolas Kaltz1, Kirsten Langeveld1, Michaela Malchow1, Mario Assenmacher1, Andreas Bosio1, Eleni Papanikolaou1,2 P119 P120 Good Response Rates of WJ-MSC, Comparable to BM-MSC, in the Treatment of Refractory GVHD Sílvia Torrents1, Laura Alonso2, Joaquim Vives1, Luciano Rodríguez1, Georgina Morón-Cazalilla3, Izaskun Elorza4, Maria Luz Uria2, Maria Isabel Benítez2, Rocío Parody5, Guillermo Ortí2, Maria Trabazo3, Jesús Fernandez-Sojo1, Margarita Codinach1, Laura Medina1, Isabel Badell4, Cristina Diaz de Heredia2, Sergi Querol1 P121 An “all in one” T-cell Product from non-transplantable Cord Blood Units for Virus- and leukemia-specific T-cell Immunotherapy Kyriakos Koukoulias1,2, Anastasia Papadopoulou1, Anastasios Kouimtzidis1,2, Damianos Sotiropoulos1, Minas Yiangou2, Achilles Anagnostopoulos1, Evangelia Yannaki1, Panayotis Kaloyannidis3 P122 Clinical Success of Granulocyte Transfusions in Adult Neutropenic Patients after Chemotherapy and/or Allogeneic Transplantation - Time Matters! Kira Inkari Thies, Michael Kramer, Friedrich Stölzel, Martin Bornhäuser, Johannes Schetelig, Simone von Bonin, Ralph Schneider, Kristina Hölig P123 Impact of long-term Cryopreservation of Autologous Hematopoietic Stem Cells Products Judith Desoutter, Aline Regnier, Christèle Ossart, Alexis Caulier, Véronique Harrivel, Marie Noelle Lacassagne, Jean Pierre Marolleau P124 Optimizing Lentiviral Vector Transduction to Gene Modify Cord Blood CD8+ T Cells for off-the-shelf Adoptive Cell Therapy to Treat Cancer Vania Lo Presti1, Ester Dunnebach1, Maud Plantinga1, Annelisa Cornel1, Jurgen Kuball1, Jaap Jan Boelens2, Niek van Til *1,3, Stefan Nierkens *1,4 P125 Donor Lymphocyte Infusion after Allogeneic Hematopoietic Stem Cell Transplantation. Single Centre Experience Isabel Iturrate, Analys Ruiz, Sara Martínez, Natalia García-León, Mercedes Royg, Ángela Figuera, Adrián Alegre, Beatriz Aguado P126 Case Report: Chronic Active epstein-barr Virus Infection (CAEBV) Controlled by Allogeneic Hematopoietic Stem Cell Transplantation (alloHSCT) and Transfusion of EBV-specific T-cells Elisabeth Meedt1, Daniela Weber1, Britta Eiz-Vesper2, Britta Maecker-Kolhoff3, Agnes Bonifacius2, Klaus Schwarz4,5, Myriam Lorenz4, Susanne Delecluse6,7, Henri-Jacques Delecluse6,7, Ernst Holler1, Wolfgang Herr1, Matthias Edinger1, Daniel Wolff1 P127 Incidence of late Relapse after Allogeneic Stem Cell Transplantation for Myelofibrosis Isik Kaygusuz Atagunduz, Anita Badbaran, Gaby Zeck, Christine Wolschke, Francis Ayuk, Maximilian Christopeit, Nicolaus Kröger P128 Hematopoietic Stem Cell Transplantation in Myelofibrosis: The Experience of Three University Transplant Centres in Rome Giulia Galassi1, Patrizia Chiusolo2, Raffaella Cerretti3, Walter Barberi1, Luisa Quattrocchi1, Ursula La Rocca1, Federica Sorà2, Valentina Rossi3, Giovanni Manfredi Assanto1, Mattia Brescini1, Roberto Ricci1, Roberto Latagliata1, Massimo Breccia1, William Arcese3, Andrea Bacigalupo2, Simona Sica2, Anna Paola Iori1 P129 P130 CML Relapse after Allogeneic HSCT: Survival, Treatment Efficacy and Prognostic Factors for Outcome Dunja Kampelmann, Dietrich W. Beelen, Rashit Bogdanov, Vesna Klisanin, Michael Koldehoff, Lambros Kordelas, Rudolf Trenschel, Markus Ditschkowski P131 Chronic Myeloid Leukemia: Allogeneic Hemopoietic Stem Cells Transplantation in the Era of Tyrosine Kinase Inhibitors Elena Morozova, Yuliya Vlasova, Mariya Barabanshikova, Kseniya Afanasieva, Nikolay Mamaev, Ildar Barkhatov, Alexander Alyanski, Elena Darskaya, Mariya Vladovskaya, Sergey Bondarenko, Ivan Moiseev, Boris Afanasyev P132 Reduced Intensity Allogeneic Stem Cell Transplant with Campath T-cell Depletion for Myelofibrosis in the Era of Jak Inhibitors- A Single Centre Experience Claire Horgan, Shereef Elmoamly, Alex Kanellopoulos, Richard Lovell, Shankara Paneesha, Bhuvan Kishore, Mary Dillon, Katie O’Collins, Kathy Holder, Emmanouil Nikolousis P133 Allogenic Stem Cell Transplantation in advanced Systemic Mastocytosis after Cytoreductive Treatment with Cladribine - A Single Center Experience on Two Patients Christoph Buhl1, Emin Abdullayev1, Johanna Kerschbaum1, Herrad Baurmann1, Andreas Reiter2, Bertram Glaß1 P134 Allogeneic Stem Cell Transplantation for Idiopatic Myelofibrosis: A Single Centre Experience Matteo Parma1, Elena Elli1, Elisa Diral2, Elisabetta Terruzzi1, Marilena Fedele1, Rossella Renso1, Andrea Aroldi2, Giovanni Zambrotta2, Pietro Pioltelli1, Carlo Gambacorti Passerini1,2 P135 A case of Successful Second Haploidentical Bone Marrow Transplantation after Secondary Graft Failure in a Patient with Refractory Chronic Myeloid Leukemia Nadezhda Shnalieva, Anna Melikhova, Iurii Osipov, Galina Salogub, Vladimir Ivanov, Elza Lomaia P136 Combining Clofarabine and Fludarabine with Exposure Targeted Busulfan for Pediatric Leukemia: An Effective, Low Toxic, TBI-free Conditioning Regimen Anne Birgitta Versluys1,2, Coco de Koning2, Marc Bierings1,2, Stefan Nierkens1,2, Caroline Lindemans1,2, Dorine Bresters1,3, Wouter Kollen1,3, Arjan Lankester3, Jaap Jan Boelens2,4 P137 Benda-beam High-dose Therapy Prior to auto-sct is Effective in Resistant/relapsed DLBCL: A Phase II Study Giuseppe Visani1, Federica Loscocco1, Stefano Guidi2, Potito Scalzulli3, Attilio Olivieri4, Emanuele Angelucci5, Saveria Capria6, Francesca Patriarca7, Barbara Castagnari8, Francesco Angrilli9, Daniele Vallisa10, Gerardo Musuraca11, Andrea Mengarelli12, Piero Galieni13, Francesco Gaudio14, Patrizia Tosi15, Pierluigi Zinzani16, Alberto Bosi2, Nicola Cascavilla3, Barbara Guiducci1, Marco Rocchi17, Alessandro Isidori1 P138 Reduced-toxicity Conditioning with Fludarabine, Thiotepa and Melphalan in Allogeneic Hematopoietic Cell Transplantation for Patients with Impaired Lung Function Jesus Duque-Afonso, Gabriele Ihorst, Miguel Waterhouse, Robert Zeiser, Ralph Wäsch, Hartmut Bertz1, Mehtap Yücel, Thomas Köhler, Joachim Müller-Quernheim, Reinhard Marks, Jürgen Finke P139 Allogeneic Stem Cell Transplant with minimal-intensity Conditioning in Patients with Cutaneous T-cell Lymphoma. A Single Centre Retrospective Review Marianne Gallanagh1, Amy Brown1, Angharad Pryce1, Richard Szydlo2, Stephen Morris3, Renuka Palanicawandar1, Edward Kanfer1 P140 Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Acute Lymphoblastic Leukemia and Karnofsky Performance Status Score Equal or Lower Than 80%. A Study from the ALWP-EBMT Francesco Saraceni1, Myriam Labopin2, Riitta Niittyvuopio3, Gerard Socié4, Nicolaus Kröger5, Edouard Forcade6, Paul Browne7, Péter Reményi8, Jan Cornelissen9, Stephen Robinson10, Ibrahim Yakoub-Agha11, Thierry Lamy12, Eolia Brissot2, Bipin Savani13, Arnon Nagler14, Mohamad Mohty2 P141 A Prospective Cohort Study Comparing long-term Outcomes with and without Palifermin in Patients Receiving Hematopoietic Cell Transplantation for Hematologic Malignancies Wael Saber1, Patricia Steinert1, Mei-Jie Zhang1,2, Min Chen1, Andrea Pope1, Armand Keating3, John Wingard4, Karen Ballen5, Patrick Stiff6, Miguel-Angel Perales7, Stephen Forman8, Richard Champlin9, Amelia Langston10, Torbjörn Kullenberg11, Mattias Rudebeck11, Mary Horowitz1 P142 Pharmacokinetics of Melphalan in Lymphoma Patients undergoing Beam and Autologous Hematopoietic Stem Cell Transplant Parastoo Dahi1,2, Andew Lin1, Jessica Flynn1, Christian Uruburo1, Ian Mcgeary1, Ryan Schofield1, Valkal Bhatt1, Lauren Derespiris1, Bradley Figgins1, Meagan Griffin1, Carmen Lau1, Anthony Proli1, Dean Carlow1, Christina Cho1,2, Oscar Lahoud1,2, Miguel Perales1,2, Craig Sauter1,2, Michael Scordo1,2, Gunjan Shah1,2 P143 Comparison of Total Body Irradiation- vs chemotherapy-based Conditionings for Early Complications of Allogeneic Hematopoietic Stem Cell Transplantation in Children with All Koray Yalcin1, Berrin Pehlivan2, Gulsun Karasu1, Vedat Uygun3, Seda Ozturkmen3, Hayriye Daloglu3, Suna Celen1, Dayanat Pashayev1, Elif Gulsah Bas2, Canan Kabakci2, Fugen Pekun1, Volkan Hazar1, Akif Yesilipek1 P144 Differential Alemtuzumab Dosages in T-cell Deplete Allogeneic Haematopoietic Stem Cell Transplants for Myeloid Malignancies Varun Mehra1, Daniele Avenoso1, Ximena C Castellano1, Adrian Choy1, Stefani Widya2, Mili Shah1, Shafqat Inam1, Shreyans Gandhi1, Austin Kulasekararaj1, Pramila Krishnamurthy1, Francesco Dazzi1, Hugues de Lavallade1, Victoria Potter1, Ghulam J Mufti1, Tony Pagliuca1 P145 Novel Reduced Intensity Conditioning (RIC) Approach to Allogeneic Hematopoietic Cell Transplantation (HCT) in Patients with Benign and Malignant Disorders of T Cell Proliferation or Dysregulation Dimana Dimitrova1, Gulbu Uzel2, Luigi D. Notarangelo2, Amanda K. Ombrello3, Deborah Stone3, Mark Parta4, Ellen Carroll1, Jennifer Wilder4, Stephanie N. Hicks1, Jennifer L. Sadler1, Daniel H. Fowler1, Ronald E. Gress1, Christopher G. Kanakry1, Jennifer A. Kanakry1 P146 Profound Lymphopenia at the time of anti-thymocyte Globulin Administration is not Predictive of Survivals after allo-transplantation Maxime Jullien1, Thierry Guillaume1, Pierre Peterlin1, Alice Garnier1, Amandine Le Bourgeois1, Camille Debord1, Beatrice Mahe1, Viviane Dubruille1, Soraya Wuilleme1, Nicolas Blin1, Cyrille Touzeau1, Thomas Gastinne1, Benoit Tessoulin1, Yannick Le Bris1, Marion Eveillard1, Alix Duquesne2, Philippe Moreau1, Steven Le Gouill1, Marie C Bene1, Patrice Chevallier1 P147 Lipid Core Nanoparticles as Vehicle for Etoposide in the Conditioning Regimen of Marrow Transplantation in Acute Myeloid Leukemia not Responding to Induction Therapy: Pilot Study Sandra Serson Rohr1,2, Raul Cavalcante Maranhao3,4, Thauany Martins Tavoni3, Aleksandra Tiemi Morikawa3, Debora Fernandes Deus3, Jose Salvador Rodrigues Oliveira1,2 P148 A Phase II Study to Investigate the Efficacy of short-term Everolimus in Addition to post-transplant Cyclophosphamide as graft-versus-host-prophylaxis after Allogeneic Stem Cell Transplantation (Octet-ever) Udo Holtick1, Marco Herling1, Lukas P Frenzel1, Carmen Herling1, Joanna Schiller1, Marta Rebecca Cruz Aguilar1, Sebastian Theurich2, Michael Hallek1, Christof Scheid1 P149 Allogeneic Stem Cell Transplantation in Patients ≥ 65 Years with Hematological Malignancies after Myeloablative treosulfan-based Conditioning: Results in 118 Patients Simona Piemontese1, Lorenzo Lazzari1, Magda Marcatti1, Fabio Giglio1, Raffaella Greco1, Daniela Clerici1, Maria Teresa Lupo Stanghellini1, Andrea Assanelli1, Francesca Farina1, Francesca Lorentino1, Sara Mastaglio1, Sarah Marktel1, Matteo Carrabba1, Consuelo Corti1, Massimo Bernardi1, Jacopo Peccatori1, Fabio Ciceri1,2 P150 P151 Fludarabine-melphalan Conditioning Results in Favorable leukemia-free Survival after Allogeneic Transplantation in Patients with Active or Measurable Residual AML Kathryn Bower1, Madiha Siraj2, Jongphil Kim1, Biwei Cao1, Hany Elmariah1, Lia Perez1, Asmita Mishra1, Taiga Nishihori1, Farhad Khimani1, Rawan Faramand1, Aleksandr Lazaryan1, Hugo Fernandez3, Michael Nieder1, Dan Sullivan1, Joseph Pidala1, Claudio Anasetti1, Nelli Bejanyan1 P152 Sequential Conditioning: Flamsa-TBI versus flamsa-treo in High Risk Acute Myeloid Leukemia (AML) in First Complete Remission and High Risk Myelodysplastic Syndrome (MDS) Elisa Sala, Verena Wais, Mai Thanh Nguyen, Adela Neagoie, Marie-Luise Hütter-Krönke, Andrea Gantner, Hartmut Döhner, Donald Bunjes P153 Increased non-relapse Mortality and Poor Overall Survival in Elderly Patients Treated with Fludarabine and Myeloablative Dose of Busulfan: Transplant Complications Working Group of the JSHCT Akihito Shinohara1, Michiho Ebihara1, Nobuaki Nakano2, Emiko Sakaida3, Naoyuki Uchida4, Kentaro Fukushima5, Hitoshi Sakai6, Takashi Ashida7, Yoshinobu Kanda8, Junji Tanaka1, Takahiro Fukuda9, Yoshiko Atsuta10,11, Hideki Nakasone8 P154 Total Marrow and Lymphoid Irradiation (TMLI) in Combination with Cyclophosphamide and Etoposide improves the Outcome of Patients with poor-risk Acute Leukemia Anthony Stein, Ni-Chun Tsai, Joycelynne Palmer, Ibrahim Aldoss, Haris Ali, Ahmed Aribi, Len Farol, Chatchada Karanes, Samer Khaled, An Liu, Guido Marcucci, Ryotaro Nakamura, Vinod Pullarkat, Eric Radany, Joseph Rosenthal, Amandeep Salhotra, Ricardo Spielberger, David S Snyder, Stephen J Forman, Monzr M Al Malki, Jeffrey Wong P155 A CD45-targeted Antibody Drug Conjugate Enables Allogeneic Hematopoietic Stem Cell Transplantation as a Single Agent in Mice Sharon Hyzy1, Rahul Palchaudhuri1, Jennifer Proctor1, Bradley Pearse1, Ganapathy Sarma1, Geoff Gillard1, Asim Saha2, Tahirih Lamothe1, Melissa Brooks1, Katelyn Hammond1, Anjali Bhat1, Charlotte McDonagh1, Hans-Peter Kiem3, John Wagner2, Bruce Blazar2, Anthony Boitano1, Michael Cooke1 P156 Final Results of a Prospective, Multicenter, non-interventional Study on thiotepa-based Autologous Hematopoietic Cell Transplantation (ASCT) for CNS or non-CNS Lymphoma Herbert Gottfried Sayer1, Mathias Witzens-Harig2, Mohammad Wattad3, Agnieszka Korfel4, Inken Hilgendorf5, Georg-Nikolaus Franke6, Gerald Illerhaus7, Michael Heinsch8, Bernd Metzner9, Eva Bettina Zinngrebe10, Nadezda Basara11, Mascha Binder12, Mark Ringhoffer13, Alexander Röth14, Thomas Geer15, Volker Schmidt1, Peter Dreger2 P157 Post-Transplant Cyclophosphamide (PT-CY), Cyclosporin (CSA) and Mycophenolate (MMF) for Patients Grafted from HLA Identical Siblings or Matched Unrelated Donors Andrea Bacigalupo1, Patrizia Chiusolo1, Federica Sora1, Luca Laurenti1, Sabrina Giammarco2, Elisabetta Metafuni2, Idanna Innocenti2, Francesco Autore2, Alessia Di Giovanni2, Eleonora Alma2, Silvia Bellesi2, Simona Sica1 P158 Conditioning Regimen Comparison for Allogeneic Stem Cell Transplantation in non-hodgkin Lymphoma Kristen Peterson, Andrew Lin, Josel Ruiz, Junting Zheng, Sean Devlin, Gunjan Shah, Michael Scordo, Craig Sauter, Miguel Perales, Sergio Giralt, Larry Buie, Parastoo Dahi P159 A Thiotepa Based Intensified Reduced Intensity Conditioning Regime in Adult Cord Blood Transplant is a Promising Alternative in Patients Unable to Receive Myeloablative Conditioning Ian Wu1, Tangia Muquith1, Yeh Ching Linn2, Michelle Poon1, Lip Kun Tan1, Belinda Tan1, Yelly Yelly1, Teck Guan Soh1, Davanaliz Gonzales Ramos1, William Hwang2, Liang-Piu Koh1 P160 Haploidentical Stem Cell Transplantation with post-transplant Cyclophosphamide using as Conditioning Fludarabine Melphalan plus low Doses of Total Body Irradiation. Long term follow-up of 60 Patients Amado Jose Karduss, Rosendo Perez, Giovanni Ruiz, Angelica Cardona, Juan Alejo Jimenez, Luis Rodolfo Gomez, Pedro Reyes P161 Comparison of Beam and Team as Conditioning Regimen for Lymphoma Patients undergoing Autologous Stem Cell Transplantation Elif Birtas Atesoglu1, Burak Deveci2, Imran Dora1, Cigdem Eren1, Suat Celik1, Gokhan Kusdemir1, Esra Bayrak1, Ihsan Karadogan2, Zafer Gulbas1 P162 Assessment of the Safety and Efficacy of the Conditioning Regimen Beeac before auto-hsct for the Treatment of primary-refractory and Relapsed forms of Malignant Lymphomas Anastasiia Samoylova, Vladislav Sarzhevsky, Vladimir Melnichenko, Nikita Mochkin, Julia Dubinina, Elena Smirnova, Anna Bannikova, Vladimir Bogatyrev P163 Allogeneic Stem Cell Transplantation after total-body Irradiation using Helical Tomotherapy - A Single Center Experience Thomas Heinicke, Ana-Maria Waldleben, Denise Wolleschak, Thomas Brunner, Günther Gademann, Thomas Fischer, Hans-Joachim Ochel P164 Feasibility of CLAMSA-RIC as an Alternative Conditioning Regimen Compared to FLAMSA-RIC in Heavily Pretreated Refractory AML Patients - A Retrospective Single Center Analysis Krischan Braitsch, Alix Pianka, Kathrin Holzhauser, Katharina Götze, Florian Bassermann, Peter Herhaus, Mareike Verbeek P165 Flamsa-based High-dose Sequential Conditioning Regimen followed by Allogeneic Hematopoietic Stem Cell Transplantation(ALLO-HSCT): Is It Effective in Patients with Primary Refractory or Relapsed Acute Leukemia? Guldane Cengiz Seval, Ekin Kircali, Sinem Civriz Bozdag, Selami Kocak Toprak, Meltem Kurt Yuksel, Onder Arslan, Muhit Ozcan, Taner Demirer, Gunhan Gurman, Osman Ilhan, Hamdi Akan, Meral Beksac, Pervin Topcuoglu P166 Increasing in Serum total Amylase Levels After Total Body Irradiation Conditioning Regimen as a Predictive Marker of transplant-related Mortality in Pediatric Hematopoietic Stem Cell Recipients Antonio Grasso1, Rossella Vidimari2, Francesca Ciriello2, Roberto Simenone3, Fabrizio Cupardo2, Natalia Maximova4 P167 Evolution of Donor Chimerism after Haploidentical Stem Cell Transplant - Clinical Correlations Carla Alves, Nuno Miranda, Pedro Sousa, Isabelina Ferreira, Gilda Teixeira, Ana Sofia Jorge, Maria Joao Gutierrez, Fernando Leal-da-Costa, Manuel Abecasis P168 Thiotepa-busulfan-fludarbine as Conditioning Regimen for Patients with Myelofibrosis undergoing Allogeneic Hematopoietic Stem Cell Transplantation: A Single Center Experience Mara Memoli1,2, Annalisa Paviglianiti1, Florent Malard1,3,4, Giorgia Battipaglia1,4, Eolia Brissot1,3,4, Clémence Médiavilla1,4, Antonio Bianchessi1,5, Anne Banet1, Zoé Van de Wyngaert1, Tounes Ledraa1, Ramdane Belhocine1, Simona Sestili1, Simona Lapusan1, Agnès Bonnin1, Anne Vekhoff1, Ollivier Legrand1,3,4, Mohamad Mohty1,3,4, Rémy Duléry1,3,4 P169 The Results of Allogeneic Hematopoietic Stem Cell Transplantation from HLA-haploidentical Donor with post-transplant Cyclophosphamide Regimen in Children Alexandra Burya1, Kirill Kirgizov2, Yulia Nikolaeva1, Veronica Konstantinova1, Ekaterina Pristanskova1, Natalia Sidorova1, Anastasia Mezenceva1, Ludmila Olhova1, Oxana Blagonravova1, Olga Filina1, Larisa Petrova1, Elena Skorobogatova1 P170 Analysis of Differences in Preventive Measures after high-dose Cyclophosphamide Among Belgian Stem Cell Transplant Centres Eva De Backer, Dries Deeren P171 Irradiation-free Re-conditioning for T-cell Depleted haplo-identical Stem Cell Transplantation Susanne Aydin, Ingo Müller P172 Low Graft CD4 Cell Dose Predicts Relapse in the Atg‐based Myeloablative Conditioning Regimen Nabil Yafour1,2, Faiza Serradj1, Soufi Osmani1, Mohamed Brahimi1,2, Sihem Bekadja1, Amel Mihoubi1, Rachid Bouhass1,2, Abdessamad Arabi1,2, Mohamed Amine Bekadja1,2 P173 P174 Haplo-identical Hematopoietic Stem Cell Transplantation (HSCT) in high-risk Hematological Malignancies, Algerian Experience Dina Ait Ouali, Malek Benakli, Farih Mehdid, Sabrina Akhrouf, Nadia Rahmoune, Mounira Baazizi, Hanane Bouarab, Sara Zerkout, Imene Abderrahim, Farida Harieche, Rose-Marie Hamladji, Redhouane Ahmed Nacer P175 Interruption of Conditioning for allo-HCT does not affect Clinical Outcomes other than Chronic GVHD Satoru Matsushima1, Ryoji Kobayashi1, Daiki Hori1, Masato Yanagi1, Koya Kodama1, Daisuke Suzuki1, Atsushi Manabe2, Kunihiko Kobayashi1 P176 Reduced Intensity Conditioning followed by Haploidentical Hematopoietic Cell Transplantation (Ric-haploHCT) and post-transplant Cyclophosphamide as Graft versus Host Disease Prophylaxis, for Hematological Disorders: Single Centre Experience Vinod Patil, Reghu Sukumaran, Mita Roychowdhury, Sayak Chaudhuri, Jeevan Kumar, Saurabh Bhave, Rizwan Javed, Niharendu Ghara, Reena Nair, Vivek Radhakrishnan, Mammen Chandy P177 Describe and Explore a Patients´ Outlook on Dental Care in the Context of their Medical Diagnosis and Treatment Prior to and following Allogeneic HSCT Charlotte Wilson-Dewhurst1,2, Amit Patel3, Shelagh Thompson2 P178 Safety and Efficacy of low-dose Benda-EAM as Compared to Beam Conditioning for Autologous Transplantation of Refractory/relapsed Lymphoma Patients Naif I. AlJohani, Momen Nasani, Azhar Nawaz, Hosam Eldin Ali, Jalil Ur Rehman Khan P179 Conditioning Regimen with Fludarabin/treosulfan Compared to Busulfan/cyclophosphamid Prior to Allogeneic Stem Cell Transplantation in Younger Patients with AML And MDS: A Single Center Retrospective Analysis Alix Pianka, Peter Herhaus, Krischan Braitsch, Katrin Holzhauser, Katharina Götze, Florian Bassermann, Mareike Verbeek P180 Atg in Conditioning for Sibling Allogeneic Stem Cell Transplantation; Single Center Experience Lazar Chadievski, Aleksandra Pivkova Veljanovska, Irina Panovska Stavridis, Zlate Stojanoski, Lidija Cevreska, Nevenka Ridova, Marija Popova Labacevska, Zaklina Ancevska, Gabriela Trajkovska, Borce Georgievski P181 2nd allo-hsct for Patients who Diagnosed Recurrence all after the 1st allo-hsct Li Nan-nan1, Zhang Jian-ping1, Lu Pei-hua1, Lu Yue1, Zhao Yan-li1, Zhou Jia-rui1, He Jun-bao2, Yang Jun-fang1, Fan Li-jun1, Yin Dong-xu1, Gao Xin-xia1, Lu Dao-pei2 P182 Establishing a Transplant Sharing Program Iryna Luts1, Maria Calbacho2, Ana Lerma1, Juan Churruca3, Maria Dolores Martínez1, Jose Maria Sanchez-Pina2, Maria Isabel Ustariz1, Maria Jesus García1, Ana Jiménez-Ubieto2, Sonia del Valle1, José Ángel Hernández-Rivas3, Joaquín Martínez-Lopez2, Fernando Solano1, Juan José Lahuerta2 P183 Impact of Gut Fungal Composition on Outcome after Allogeneic Hematopoietic Cell Transplantation Florent Malard1, Aonghus Lavelle2, Giorgia Battipaglia1, Béatrice Gaugler2, Rémy Dulery1, Eolia Brissot1, Tounes Ledraa1, Razan Mohty1, Harry Sokol2, Mohamad Mohty1 P184 Monitoring Hematopoietic Cell Microparticles in Allografts and Transplant Recipients Angeliki Xagorari, Michail Iskas, Christos Demosthenous, Dimitris Bougiouklis, Despoina Papadopoulou, Ioanna Sakellari, Achilles Anagnostopoulos, Damianos Sotiropoulos P185 Ex-vivo Autologous Haematopoietic Stem Cell Gene Therapy in Mucopolysaccharidosis Type IIIA Jane Kinsella1, Simon Jones2, Heather Church3, Ceri Jones3, Stuart Ellison4, Claire Booth5, Karen Buckland5, Diego Leon Rico5, Brian Bigger4, Adrian J Thrasher5, Robert Wynn1 P186 Identification of Predictive Models Including Polymorphisms in Cytokines Genes Associated with Acute Graft versus Host Disease and overall Survival after Identical HLA-allogeneic Stem-cell Transplantation Paula Muñiz1,2, Mi Kwon1,2, Rebeca Bailén1,2, Nieves Dorado1,2, Laura Solán1,2, Diego Carbonell1,2, Julia Suárez-González1,2, María Chicano1,2, Cristina Andrés-Zayas1,2, José María Bellón2, Juan Carlos Triviño3, Javier Anguita1,2, José Luis Díez-Martín1,2,4, Carolina Martínez-Laperche1,2, Ismael Buño1,2,4 P187 Search for Circulating Endothelial Cells of Donor Origin after Allo-HSCT: Potential Clinically Relevant Implications in the Context of graft-versus-host Disease Camillo Almici1, Francesca Fontana2, Giovanna Piovani3, Piera Balzarini3, Arabella Neva1, Benedetto Bruno4, Cristina Skert3, Gianluca Rotta5, Simona Fisogni3, Rosanna Verardi1, Andrea Bianchetti1, Simona Braga1, Michele Malagola3, Nicolò Manaresi2, Fabio Facchetti3, Domenico Russo3, Mirella Marini1 P188 Double Lung Transplantation in Adults for Chronic Pulmonary Graft versus Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation Ram Vasudevan Nampoothiri1, Peter Riddell2, Susan Chernenko2, Matthew Binnie2, Lianne Singer2, Stephen Juvet2, Jeffrey Howard Lipton1 P189 Reduced Inflammatory Tissue Infiltration during Intestinal steroid-refractory GVHD Katarina Riesner1, Steffen Cordes2, Maria Bartosova3, Martina Kalupa1, Sarah Mertlitz1, Lars Bullinger1, Igor Wolfgang Blau1, Claus Peter Schmitt3, Gernot Beutel4, Olaf Penack1 P190 Impact of Antithymocyte Globulin Dose for graft-versus-host Disease Prophylaxis in Stem Cell Tansplantation from Unrelated Donors Sara Butera1,2, Marco Cerrano1, Lucia Brunello1,2, Chiara Maria Dellacasa1, Danilo Faraci1,2, Sara Vassallo2, Carolina Secreto1,2, Nicola Mordini3, Roberto Sorasio3, Francesco Zallio4, Alessandro Busca1, Benedetto Bruno1,2, Luisa Giaccone1,2 P191 Decreased Soluble HLA-e Levels in Patients after Allogeneic Stem Cell Transplantation are Associated with Severe Acute and Extended Chronic graft-versus-host Disease and Inferior overall Survival Lambros Kordelas, Esther Schwich, Monika Lindemann, Falko M. Heinemann, Ulrike Buttkereit, Peter A. Horn, Dietrich W. Beelen, Vera Rebmann P192 Effect of Extracorporeal Photopheresis on Production of Serum Soluble CD163: Relationship to Immunosuppression and Disease Activity in Chronic Graft Versus Host Disease Nick C. Mattthews, Charlotte Burton, Arun Alfred P193 Post-transplant High-dose Cyclophosphamide Overcomes the Detrimental effect of a single-locus HLA Mismatched in Unrelated Donor Allogeneic Hematopoietic Stem Cell Transplantation Alejandra Pedraza, Patricia Ferraz, Arturo Pereira, Ana Sofia Jorge, María Suárez-Lledó, Gonzalo Gutiérrez-García, Francesc Fernández-Avilés, Laura Rosinol, Teresa Solano, Noemí Llobet, Carla Ramos, Pedro Marín, Álvaro Urbano-Ispízua, Montserrat Rovira, Carmen Martinez P194 Allogeneic Peripheral Blood Transplantation with post-transplant Cyclophosphamide and Sirolimus from Haploidentical and Matched Donors: “sir-PTCY” Results in 249 Patients Raffaella Greco, Serena Albanese, Francesca Lorentino, Maria Teresa Lupo Stanghellini, Fabio Giglio, Simona Piemontese, Magda Marcatti, Daniela Clerici, Lorenzo Lazzari, Rosamaria Nitti, Carmine Liberatore, Sara Mastaglio, Andrea Assanelli, Luca Vago, Chiara Bonini, Consuelo Corti, Massimo Bernardi, Fabio Ciceri, Jacopo Peccatori P195 A New Hope in the Treatment of steroid-refractory Graft Versus Host Disease (Sr-GVHD) after Allogeneic Hematopoetic Stem Cell Transplantation (AHSCT): Ruxolitinib Osman Ilhan1, Guldane Cengiz Seval1, Sinem Civriz Bozdag1, Burak Deveci2, Mustafa Pehlivan3, Leylagul Kaynar4, Irfan Yavasoglu5, Huseyin Bekoz6, Ipek Yonal Hindilerden7, Zeynep Arzu Yegin8, Simten Dagdas9, Ayse Avsar10, Atilla Hasan Ozkan11, Tulin Firat Tuglular12, Hakan Goker10, Zafer Golbas13 P196 P197 Evaluation of the Prognostic Value of Histologic Assessment of Acute graft-versus-host-disease of the Upper Gastrointestinal Tract According to Lerner Early after Allogeneic Hematopoietic Cell Transplantation Abed Alahad Sarraf1, Renate Schmelz1, Henning Baldauf2, Daniela Aust1, Friedrich Stölzel1,2, Jan Moritz Middeke1, Katja Sockel1, Raphael Teipel1, Stefan Brückner1, Marco Berning1, Sebastian Zeissig1, Jana Babatz1, Christian Kirsch1, Gustavo Baretton1,3, Martin Bornhäuser1,3, Jochen Hampe1, Johannes Schetelig1,2 P198 Cyclosporine a Alone versus Mycophenolate Mofetil Plus Cyclosporine a Based GVHD Prophylaxis For Patients With AML undergoing Mud Transplantation. A Study from the ALWP Annalisa Paviglianiti1, Myriam Labopin1,2, Didier Blaise3, Gerard Socie4, Claude Eric Bulabois5, Bruno Lioure6, Nathalie Fegueux7, Arnim Gerbitz8, Gaelle Guillerm9, Johan Maertens10, Patrice Chevallier11, Anne Huynh12, Pascal Turlure13, Eric Deconinck14, Edouard Forcade15, Arnon Nagler2,16, Mohamad Mohty1,2,17 P199 Transplant-associated Thrombotic Microangiopathy is Independently associated with Ruxolitinib Administration in Patients with graft-versus-host-disease Eleni Gavriilaki, Ioanna Sakellari, Zoi Bousiou, Thomas Chatzikonstantinou, Despina Mallouri, Marianna Masmanidou, Anna Vardi, Eudoxia-Evangelia Koravou, Foteini Kika, Tasoula Touloumenidou, Apostolia Papalexandri, Evangelia Yannaki, Ioannis Batsis, Achilles Anagnostopoulos P200 Diagnostic Significance of Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) in Acute Intestinal graft-versus-host Disease (GVHD) Georg Evers, Wolfgang Roll, Joern Christian Albring, Christian Reicherts, Rebecca Strotmann, Georg Lenz, Michael Schaefers, Matthias Stelljes P201 Long term Outcomes of Ruxolitinib Therapy in steroid-refractory graft-versus-host Disease in Children and Adults Tatiana Bykova, Ivan Moiseev, Elena Morozova, Elena Darskaya, Olesya Paina, Anna Smirnova, Anna Dotcenko, Evgenia Borzenkova, Alexander Galimov, Yana Gudognikova, Kirill Ekushev, Polina Kozhokar, Anna Osipova, Olga Pirogova, Tatiana Rudakova, Olesya Shakeeva, Nikolay Tcvetkov, Egor Kulagin, Ludmila Zubarovskaya, Boris Afanasyev P202 P203 Efficacy and Toxicity of Ruxolitinib in Patients with steroid-resistant Acute and Chronic graft-versus-host Disease after Hematopoietic Cell Transplantation ANNA PETROPOULOU, Mitja Nabergoj, Anne-Claire Mamez, Sarah Morin, Elif Mahne, Carmen De Ramon Ortiz, Caroline Stephan, Christian Ayer, Benjamin Bruno, Laura Bounaix, Maria Anastasiou, Maria Mappoura, Carole Dantin, Yan Beauverd, Federico Simonetta, Federica Giannotti, Stavroula Masouridi-Levrat, Yves Chalandon P204 Patient Characterization and Survival Outcomes in Paediatric Chronic Graft versus Host Disease Patients - A population-based Study in Sweden Frida Schain1,2, Nurgul Batyrbekova1,3, Annica Dominicus3, Simona Baculea4, Mats Remberger5, Jonas Mattsson6,7, Jacek Toporski8 P205 Cytokine Levels following Allogeneic Hematopoietic Stem Cells Transplantation. A match-pair Analysis of Home Care Versus Hospital Care Olle Ringden, Mats Remberger, Johan Torlen, Sigrun Finnbogadottir, Britt-Marie Svahn, Behnam Sadeghi P206 Incidence of Chronic graft-versus-host Disease - Results from a Prospective Multicentre Analysis of 2 Cohorts Antonela Lelas1, Ronja Langer2, Michael Rittenschober3, Lana Desnica4, Hildegard Greinix5, Anne Dickinson6, Marit Inngjerdingen7, Anita Lawitschka3,8, Radovan Vrhovac1,4, Drazen Pulanic1,4, Stefan Klein9, Jan Moritz Middeke10, Matthias Edinger11, Daniel Wolff11 P207 Early Introduction of Ruxolinitib for Children with Graft versus Host Disease - A Stitch in Time Saves Nine Revathi Raj, Ramya Uppuluri, Venkateswaran vellaichamy, Nikila Ravichandran, Kesavan Iyer P208 Post-transplant Cyclophosphamide as an Effective Strategy For GVHD Prevention in both HLA-matched and Mismatched Allogeneic Transplants Irene García-Cadenas, Albert Esquirol, Rahinatu Awol, Silvana Saavedra, Silvana Novelli, Ana Garrido, Jordi López, Carol Moreno, Miquel Granell, Javier Briones, Salut Brunet, Jordi Sierra, Rodrigo Martino P209 Serum Autoantibodies in Allogeneic Hematopoietic Cell Transplantation (HCT) Patients: A Pilot Study Ivan Pasic1, Ashley Di Meo2, Ioannis Prassas2, Ihor Batruch2, Leeann Wilson1, Eleftherios P. Diamandis2, Fotios V. Michelis1 P210 Optimized Starting Dose of Cyclosporine Reduces Risk of Acute GVHD after Allogeneic Hematopoietic Cell Transplantation: A Single Center Experience Jérémie Héritier, Michael Medinger, Dominik Heim, Helen Baldomero, Christian Arranto, Jörg Halter, Jakob R. Passweg, Martina Kleber P211 Success of Immunosuppression in Patients with Chronic GVHD: Analysis on 108 Adult long-term Survivors after Matched and HAPLO HSCT Maria Teresa Lupo-Stanghellini1, Francesca Lorentino1, Fabio Serpenti2, Andrea Assanelli1, Carlo Messina1, Sara Mastaglio1, Stefania Girlanda1, Fabio Giglio1, Raffaella Greco1, Sarah Marktel1, Francesca Lunghi1, Elena Guggiari1, Magda Marcatti1, Matteo G. Carrabba1, Massimo Bernardi1, Consuelo Corti1, Jacopo Peccatori1, Fabio Ciceri1,3 P212 Incidence and Outcome of Liver Chronic graft-versus-host Disease During Tapering or after Stopping Calcineurin Inhibitors in Allogeneic Hematopoietic Stem Cell Transplant Recipients Kazuki Yoshimura, Shun-Ichi Kimura, Masakatsu Kawamura, Shunto Kawamura, Junko Takeshita, Nozomu Yoshino, Yukiko Misaki, Shinpei Matsumi, Ayumi Gomyo, Yu Akahoshi, Masaharu Tamaki, Machiko Kusuda, Kazuaki Kameda, Hidenori Wada, Koji Kawamura, Miki Sato, Kiriko Terasako-Saito, Aki Tanihara, Hideki Nakasone, Shinichi Kako, Yoshinobu Kanda P213 Post-transplant Cyclophosphamide after Matched Sibling and Matched Unrelated Compared to Haploidentical Donor Transplants in Patients with Acute Myeloid Leukemia, a Study on Behalf of Geth Mi Kwon1, Rebeca Bailén1, Maria Jesus Pascual Cascon2, Lucia Lopez Corral3, Arancha Bermudez4, Pilar Herrera5, Antonia Sampol6, Inmaculada Heras7, Carmen Martin Calvo8, Jaime Sanz9, Isabel Sanchez Ortega10, Melissa Torres11, Jose Rifon Roca12, Karem Humala13, Cristina Muñoz1, Ignacio Gomez Centurion1, Gillen Oarbeacoa1, Nieves Dorado1, Jose Luis Diez Martin1 P214 T-lymphocyte Transcriptional Signature in ECP-treated Paediatric Patients with Acute graft-versus-host Disease Aisling M Flinn1,2, Janet Chou3, Anna Ehrlich1, Xiao Nong Wang1, Raif S Geha3, Andrew R Gennery1,2 P215 Efficacy of low-dose Ruxolitinib as Savage Therapy in Heavily Pretreated Patients with Moderate/severe steroid-refractory Chronic graft-versus-host Disease Yanmin Zhao, Jimin Shi, Yi Luo, Yamin Tan, Jian Yu, Huarui Fu, Xiaoyu Lai, He Huang P216 Restrictive use of Intravenous Antibiotics in Allogeneic SCT Pts with Fever due to Cytokine Release Syndrome Allows Microbiota Protection without Increase of Infections and TRM Ernst Holler, Daniela Weber, Joachim Hahn, Cornelia Mittermaier, Klaus-Georg Kreitmeier, Andreas Hiergeist, Bernd Salzberger, Daniel Wolff, Andre Gessner, Wolfgang Herr, Matthias Edinger P217 Extracorporeal Photopheresis (ECP) as first-line Treatment for Acute GVHD (AGVHD) in Pediatric Patients who underwent T-depleted Haploidentical Stem Cell Transplantation (APLO-HSCT) Maria Speranza Massei1, Claudia Del Fante2, Santina Recupero2, Ilaria Capolsini1, Cristina Mortellaro2, Olivia Minelli1, Marina Onorato1, Nicola Albi1, Elisa Pierini1, Katia Perruccio1, Elena Mastrodicasa1, Grazia Gurdo1, Carla Cerri1, Francesco Arcioni1, Mauro Marchesi1, Cesare Perotti2, Marco Zecca1, Maurizio Caniglia1 P218 Micro RNA Profiling of acoustically-isolated Extracellular Vesicles Identifies Potential Biomarkers for post-allo-hsct Complications Hooi Ching Lim1, Shamit Soneji1, Robert Palmason2, Stig Lenhoff2, Thomas Laurell1, Stefan Scheding1,2 P219 Colonization Plays an Important Role in the Outcome of Allogeneic Transplantation Ilaria Cutini, Riccardo Boncompagni, Antonella Gozzini, Chiara Nozzoli, Chiara Innocenti, Massimo Di Gioia, Agata Suellen Guarrera, Giulia Raugei, Serena Maroitti, Riccardo Saccardi P220 Endothelial Activation and Stress Index (Easix) Score at the Onset of Acute graft-versus-host Disease in Predicting Outcome of Allogeneic Stem Cell transplantation-a Retrospective Analysis Lana Desnica1, Tomislav Taborsak2, Nadira Durakovic1,2, Alen Ostojic1, Ranka Serventi Seiwerth1, Radovan Vrhovac1,2, Zinaida Peric1,2 P221 Carfilzomib In addition to Standard Cyclosporine/ Methotrexate Combination Effectively Prevents Acute graft-versus-host Disease after Allogeneic Stem Cell Transplantation from Unrelated Donors Avichai Shimoni, Noga Shem-Tov, Ivetta Danylesko, Ronit Yerushalmi, Arnon Nagler P222 Comparison of Exclusive Postransplant Cyclophosphamide versus a Calcineurin Inhibitor Based Regimen as GVHD Prophylaxis in Allogeneic Bone Marrow Transplantation from HLA Identical Sibling Joan Mora Barrios, Sara Fernández Luis, Lucrecia Yáñez S., Yolanda González, David Gómez, Miguel Angel Cortés, Noemí Fernández, Sergio Fernández, José Alvaro Calvo, Juan Manuel Cerezo, Juan José Domínguez, Mercedes Colorado, Mónica López Duarte, Guillermo Martin Sanchez, Enrique Ocio, Arancha Bermúdez P223 Sirolimus versus Cyclosporine with post-transplant Cyclophosphamide and Mycophenolate as graft-versus-host Disease Prophylaxis in Haploidentical Transplants: a Retrospective Analysis of One Single Institution Mario Andres Sanchez Salinas1, Rafael Hernani Morales1, Ana Benzaquen Vallejos1, Juan Carlos Hernandez Boluda1, Ariadna Perez Martinez1, Paula Amat Martinez1, Montserrat Gomez Calafat1, Rosa Goterris Viciedo1, Carlos Solano Vercet1,2 P224 Targeted Sequence Capture Metagenomics (Virocap) to Detect Virus in Stool Samples of Hematopoietic Stem Cell Transplantation Patients Suze A. Jansen1, Wouter Nijhuis1, Helen Leavis1, Annelies Riezebos-Brilman1, Caroline A. Lindemans1,2, Rob Schuurman1 P225 Extracorporeal Photopheresis and Production of Serum IL-34 and Elafin in Chronic Graft Versus Host Disease Charlotte Burton, Nick C. Mattthews, Arun Alfred P226 Impact of Upper and Lower Acute Gastrointestinal graft-versus-host Disease on Grading And Outcome of Allogeneic Stem Cell Transplantation: A Retrospective Analysis in 122 Consecutive Patients Monica Poiani, Francesco Saraceni, Ilaria Scortechini, Giorgia Mancini, Marianna Mariani, Giorgia Micucci, Chiara Montagna, Giuseppina Urbano, Federica Monaco, Giuseppe Tarantino, Irene Federici, Attilio Olivieri P227 Preliminary Experience with the use of Ruxolitinib, Ibrutinib or Imatinib for the Treatment of Acute or Chronic GVHD Carolina Secreto, Martina Tonelli, Alessandro Busca, Matilde Scaldaferri, Chiara Della Casa, Luisa Giaccone, Lucia Brunello, Sara Butera, Giorgia Iovino, Francesco Cattel, Benedetto Bruno P228 Ruxolitinib with or without Ibrutinib as an Alternative First Line Therapy free of Corticosteroids or Calcineurin Inhibitors in Treatment of Acute graft-versus-host Disease Rong Xie1, Qin Liu2, Dan Han1, Wenlan Chen1, Han Yan1, Fanjun Cheng1, Yong You1, Ping Zou1, Zhaodong Zhong1 P229 Calcineurin-inhibitors or Sirolimus PTCy-MMF Based GVHD Prophylaxis: Comparative Study in 132 Pts Chiara Montagna1, Maria Teresa Lupo Stanghellini2, Ilaria Scortechini1, Magda Marcatti2, Raffaella Greco2, Fabio Giglio2, Andrea Assanelli2, Consuelo Corti2, Monica Poiani1, Federica Monaco1, Giuseppina Urbano1, Giorgia Mancini1, Irene Federici1, Jacopo Peccatori2, Fabio Ciceri2,3, Attilio Olivieri1,4, Simona Piemontese2 P230 Impact of KIR/HLA Incompatibilities after Posttransplant Cyclophosphamide based T cell-replete Haploidentical Hematopoietic Stem Cell Transplantation Sarah Lindner1, Tobias Berg1,2, Christian Seidl3, Franziska Kalensee4, Michael Rieger1, Hubert Serve1,5, Gesine Bug1, Joachim Schwaeble3, Evelyn Ullrich4,5 P231 Elevated PTH Levels among Chronic graft-versus-host Disease Patients and other Long term Survivors after Allogeneic Hematopoietic Stem Cell Transplantation Antonela Lelas1, Lana Desnica2, Ivan Sabol3, Zlatko Giljevic1,2, Tina Dusek1,2, Dina Ljubas Kelecic2, Irena Karas2, Nadira Durakovic1,2, Zinaida Peric1,2, Ranka Serventi Seiwerth2, Radovan Vrhovac1,2, Steven Z. Pavletic4, Drazen Pulanic1,2 P232 Concurrence of GVHD and non-infectious Neurological Complications of Hematopoietic Cell Transplantation Mohammad Sheikh1, Shahrukh Hashmi2 P233 Acute GVHD Incidence in Mismatched Unrelated Donor HSCT in Paediatric Ad Adult Patients: A Study from the Turin Metropolitan Transplant Center Massimo Berger1,2, Marta Barone1,2, Francesco Saglio1,2, Fabrizio Carnevale-Schianca2, Marco De Gobbi2,3, Luca Parnuzzo2, Paolo Nicoli2,3, Manuela Spadea1,2, Daniela Caravelli2, Elena Ernestina Vassallo1,2, Massimo Aglietta1,2, Franca Fagioli1,2 P234 Practical Implementation of the NIH Diagnostic Criteria for Oral Chronic GVHD in a Multidisciplinary Team in the Late Follow Up of Allogenic HSCT Patients Caroline Siviero Dillenburg, Alessandra Aparecida Paz, Priscila Oliveira da Silva, Liane Esteves Daudt P235 The Impact of antibiotic-mediated Modification of the Intestinal Microbiome on Outcomes of Allogeneic Hematopoietic Cell Transplantation: Systematic Review and meta-analysis Maria Gavriilaki1, Ioanna Sakellari2, Achilles Anagnostopoulos2, Eleni Gavriilaki2 P236 Clinical Application of Mesenchymal Stem Cells from Wharton’s Jelly in Patients with graft-versus-host Disease Michał Piątek1, Izabela Zdolińska-Malinowska1, Maciej Rojek1, Monika Mielcarek-Siedziuk2, Krzysztof Kałwak2, Katarzyna Drabko3, Agnieszka Zaucha-Prażmo3, Dominik Grabowski3, Janina Marta Choma3, Mirosław Markiewicz4, Monika Dzierzak Mietla5, Jolanta Goździk6, Szymon Skoczeń7, Krzysztof Czyżewski8, Robert Dębski8, Anna Krenska8, Jan Styczyński8, Mariusz Wysocki8, Dariusz Boruczkowski1 P237 Predictive Role of Endoscopic/histological Examinations for gastro-intestinal Acute Graft versus Host Disease after Allogeneic Stem Cells Transplant: “a Posteriori” Analysis in a Single Center Giuseppe Tarantino, Monica Poiani, Francesco Saraceni, Ilaria Scortechini, Giorgia Mancini, Giuseppina Urbano, Irene Federici, Marianna Mariani, Giorgia Micucci, Attilio Olivieri P238 The Incidence, Risk Factors, and Outcomes of Acute graft-versus-host Disease in Pediatric Haploidentical Hematopoietic Stem Cell Transplantation Fei-Fei Tang1, Yi-Fei Cheng1, Lan-Ping Xu1, Xiao-Hui Zhang1, Chen-Hua Yan1, Wei Han1, Yu-Hong Chen1, Xiao-Jun Huang1,2, Yu Wang1,3 P239 Prognostic CT findings around the Onset of Acute Gastrointestinal graft-versus-host Disease Shinpei Harada1,2, Koichiro Minauchi2, Hajime Senjo3, Naoki Miyashita4, Tomohiro Yamakawa2, Junko Iwasaki2, Shojiro Takahashi2, Kohei Okada2, Akio Shigematsu2, Masahiro Imamura2, Naoki Kobayashi2, Shuichi Ota2 P240 Thymoglobulin and Grafalon effect on Allogeneic Stem Cell Transplant - Pooled Data from Wroclaw Medical University, Poland and University Medical Center Ljubljana, Slovenia Anna Czyz1, Nika Zima2, Agnieszka Szeremet1, Maciej Majcherek1, Polona Novak2, Barbara Skopec2, Matevz Skerget2, Njetocka Gredelj Simec2, Samo Zver2, Donata Urbaniak-Kujda1, Iwona Prajs1, Tomasz Wrobel1, Matjaz Sever2 P241 The Role of low-dose Anti-thymocyte Globulin in Matched Sibling Donor Peripheral Blood Stem Cell Transplantation for Hematologic Malignancies Daihong Liu, Liping Dou, Lu Wang, Fei Li, Lijun Wang P242 Nephrotic Syndrome after Allogeneic Stem Cell Transplantation as a form of Chronic Graft versus Host Disease: Single Center Experience Patricia López Pereira, Ángela Figuera Álvarez, Elena Sola Aparicio, Adrian Alegre Amor, Beatriz Aguado Bueno P243 Correlation among Total Nucleated Cells (TNC), CD34+, CD3+ Cell Content in G-CSF-primed Bone Marrow Collections and their Relative Influence on Development of Acute GVHD Stalin Ramprakash1,2, Rajat Kumar Agarwal2, C P Raghuram1,3, Pallavi Mehta2, Paula Tacia2, S Sandeep2, Rakesh Dhanya2, Lawrence Faulkner2,4 P244 Prediction for Lethal Acute Graft versus Host Disease and non-relapse Mortality By Early Plasma Biomarkers; a Single Center Retrospective Study in Japan Hideaki Yoshimura, Atsushi Satake, Masaaki Hotta, Takahisa Nakanishi, Aya Nakaya, Shinya Fujita, Tomoki Ito, Kazuyoshi Ishii, Shosaku Nomura P245 Ruxolitinib in the treatment of corticosteroid-refractory graft-versus-host Disease (GVHD). One Single Center Experience Melissa Torres Ochando, Paula Fernández-Caldas González, Haridian de la Nuez Melián, Cynthia Acosta Fleitas, Santiago Jiménez Bravo de Laguna, María Perera Álvarez, Leslie González Pinedo, Luisa Guerra Domínguez, Alexia Suárez Cabrera, Luz María González del Castillo, Leonor Pérez Ortiz, Teresa Molero Labarta P246 Outcome of Patients alive at 1-year Post Allogeneic Stem Cell Transplantation: A Retrospective Analysis from a Single Institution Ana Benzaquen Vallejos1, Rafael Hernani Morales1, Mario Andres Sanchez Salinas1, Ariadna Perez Martinez1, Juan Carlos Hernandez Boluda1, Rosa Goterris Viciedo1, Montserrat Gomez Calafat1, Carlos Solano Vercet1,2 P247 Ruxolitinib in steroid-refractory Chronic graft-versus-host Disease: Experience in our Centre Sofia Martin-Consuegra Ramos, Isabel Izquierdo Garcia, Marta Moreno Carbonell, Carlos Hernandez Mata, Ana Gomez Martinez, Sergio Pinzon Mariño, Alejandro Garcia Ortego, Eduardo Gonzalez Gomez, Pilar Delgado Beltran P248 Low-dose of Ruxolitinib: An Effective Therapy for Refractory Bos Patients Yanping Ji1, Baolin Tang2, Xiaoyu Zhu2, Huilan Liu2, Kaidi Song2, Xiang Wan2, Wen Yao2, Guangyu Sun2, Zimin Sun1,2 P249 Detection of Biomarkers Predictive of graft-versus-host Disease in Allogeneic Hematopoietic Cell Transplantation (HCT) Patients: A Pilot Study Ivan Pasic1,2, Ashley Di Meo2,3, Ioannis Prassas3, Ihor Batruch3, Leeann Wilson1, Eleftherios Diamandis2,3, Fotios Michelis1,2 P250 Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation (ALLO-HSCT) After PD-1 Blockade in Relapsed/Refractory (R/R) Lymphomas -A Single Center Experience Xabier Gutiérrez López de Ocariz, Elena Vera-Guerrero, María Calbacho, Jose María Sánchez-Pina, Ana Jiménez-Ubieto, Antonia Rodríguez, Sara Redondo, Marta Hidalgo-Soto, Rodrigo De Nicolás, Nieves López-Muñoz, Buenaventura Buendía-Ureña, Joaquín Martínez-López P251 CD3+ Dose in Peripheral Blood Progenitor Cells Products for Allotransplant from Matched Unrelated Donors for AML: Impact on Chronic Graft Versus Host Disease and Survival Patricia López Pereira, Carmen Cámara Montejano, Ángela Figuera Álvarez, Cecilia Muñoz Calleja, Isabel Vicuña Andrés, Beatriz Aguado Bueno P252 A Role of Methotrexate in the Therapy of Chronic graft-versus-host Disease - A Multicenter Observational Study on Behalf of Polish Adult Leukemia Group (PALG) Agnieszka Piekarska1, Magdalena Dutka1, Alicja Sadowska-Klasa1, Ewa Karakulska-Prystupiuk2, Małgorzata Sobczyk-Kruszelnicka3, Anna Czyż4 P253 Evaluation of Extracorporeal Photopheresis used as second-line Treatment for graft-versus-host Disease After Allogeneic HSCT in a Brazilian Center Paula Moreira da Silva, Jimmy Paoly Garate, Lorena Bedotti Ribeiro, Carlos Sitta Sabaini, Vanessa Almeida Padua, Alessandra Degrande Petta, Maria Fernanda Vasques Esteves, Neysimelia Costa Villela, Patricia Shimoda Ikeuti, George Mauricio Navarro Barros P254 Analysis of Histology’s Impact in Patients with Acute Graft versus Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation Elena María Gámez Jiménez, Pedro Antonio González Sierra, Elisa López Fernández, Lucía Moratalla López, Zoraida Mesa Morales, Antonio Romero Aguilar, Manuel Jurado Chacón P255 Ruxolitinib in Chronic Graft Versus Host Disease: Single Center Experience Elif Birtas Atesoglu, İmran Dora, Cigdem Eren, Suat Celik, Gokhan Kusdemir, Demet Cekdemir, Kader Caliskan, Zafer Gulbas P256 Impact of post-transplant Cyclophosphamide(CYPT) for graft-versus-host Disease (GVHD) Prophylaxis in Allogenic Hematopoietic Stem Cell Transplantation (ALLO-HSCT). Unicentric Experience Clara Cuéllar Pérez-Ávila1, Begoña Pérez de Camino Gaisse2, Javier Cornago Navascués2, Ana Lerma Verdejo3 P257 Early Recovery of Lymphocytes after Hematopoietic Stem Cell Transplantation is Risk Factor of CGVHD Masato Yanagi, Ryoji Kobayashi, Satoru Matsushima, Daiki Hori, Koya Kodama, Daisuke Suzuki, Kunihiko Kobayashi P258 Combined Therapy with MSC Infusions to Overcome steroid-dependency in a Case of Severe Pulmonary CGVHD Francesca Compagno, Antonia Avanzini, Elena Bergami, Stella Boghen, Tommaso Mina, Santina Recupero, Elisa Lenta, Stefania Croce, Laura Catenacci, Alessandra Tolva, Federico Bonetti, Giovanna Giorgiani, Patrizia Comoli, Marco Zecca P259 Multiple Strictures of the Small Intestine Demanding Surgical Intervention as a Complication of Graft versus Host Disease - Case Report Agnieszka Sobkowiak-Sobierajska, Michał Błaszczyński, Agata Szłapińska, Anna Pieczonka, Maksymilian Deręgowski, Katarzyna Wachowiak-Szajdak, Przemysław Mańkowski, Jacek Wachowiak P260 A Remarkably Long Remission Achieved with Ibrutinib Monotherapy in a Patient who was Diagnosed with Steroid Refractory Sclerosing Chronic GVHD Ömür Gökmen Sevindik1, Mustafa Merter2 P261 Increased Risk of Acute GVHD in Patients with Myelofibrosis after Allo Transplant in the Absence of jak-stat Inhibition SAMI BRAKE P262 Autoimmune Myositis as Paraneoplastic Complication of a Squamous Cell Carcinoma of the Tongue after Severe Chronic Graft versus Host Disease Pascal Woelfinger, Beate Hauptrock, Wilfried Wagner, Andreas Schwarting, Matthias Theobald, Eva Maria Wagner-Drouet P263 Unusual Cause of Dyspnea in post-transplant Patient Sergio Felipe Pinzón Mariño, Alejandro José García Ortego, Isabel Izquierdo García, Lissette Costilla Barriga, Beatriz de Rueda Ciller, Carlos Francisco Hernández Mata, Ana Gomez Martínez, Sofía Martín-Consuegra Ramos, Marta Moreno Carbonell, Eduardo Gonzalez Gomez, María Civeira Marin, Pilar Delgado Beltran P264 Enhancing Regulatory T Cell Function and Homing to the Gut to Improve graft-versus-host Disease Prevention after Adoptive Transfer in Allogeneic Hematopoietic Transplantation Antonella Mancusi1, Samanta Bonato1, Rachele Del Sordo1, Sara Piccinelli1, Eni Hoxha1, Tiziana Zei2, Roberta Iacucci Ostini2, Franca Falzetti1, Alessandra Carotti1, Loredana Ruggeri1, Michele Giansanti1, Robert S. Negrin3, Massimo F. Martelli1, Andrea Velardi1, Antonio Pierini1 P265 LYG1-deficient Donor Splenocytes Attenuated the Severity of Acute graft-versus-host Disease Via Skewing CD4+T Cell Polarization Towards Treg Cells Huihui Liu, Zhengyu Yu, Bo Tang, Shengchao Miao, Chenchen Qin, Miao Yan, Zhengyang Song, Hanyun Ren, Yujun Dong P266 Attenuation of Murine Chronic Graft versus Host Disease by the Nrf2 Activator Mangiferin Kang Sun1, Ping Chen1, Mengran Lee1, Jun Ruan1, Yuxue Xia1, Mei Hong1, Jun Fang1, Hao Tang2 P267 Chemotherapy and Inflammation Induced Damage of Intestinal Epithelium is associated with Increased T Cell Chemotaxis Suze A. Jansen1, Marliek van Hoesel1, Michal Mokry1, Leire Saiz Sierra1, Shuichiro Takashima2, Edward E.S. Nieuwenhuis1, Alan M. Hanash2, Caroline A. Lindemans1,3 P268 Inkt Cells Promote Immune Tolerance by Selective Dendritic Cell Apoptosis Emmanuelle Moraes Ribeiro, Hannes Schmid, Ruoyun Dong, Kathy-Ann Secker, Hildegard Keppeler, Corina Schneidawind, Dominik Schneidawind P269 A Murine Model Reveals A Critical Role for Reactive Oxygen Species in Hyperacute graft-versus-host Disease Yigeng Cao1, Erlie Jiang1, Jiro Sakai2, Mengnan Lyu1, Sizhou Feng1, Xiaoming Feng1, Hongbo Luo2, Jiaxi Zhou1, Mingzhe Han1, Yuanfu Xu1 P270 Mapping the Road of GVHD and GVT. A Longitudinal Study of immune-transcriptome Signatures as Novel Approach to Solve post-allogeneic Transplantation Dilemmas Merav Bar1, Mohammed Toufiq2, Darawan Rinchai2, Mohammed Elanbari2, Sabri Boughorbel2, Valentina Mattei2, Rebecca Mathew2, Irene Cavattoni3, Sabine Forer3, Clarisa Brown1, Marco Zecca4, Patrizia Comoli4, Giovanni Grillo5, Catherine Cole2, Chiara Cugno2, Sara Tomei2, Damien Chaussabel2, Sara Deola2 P271 Cell-free DNA Levels are Increased in Acute graft-versus-host Disease in Patients and Mice Anna Kroeze1, Anne Cornelissen1, Fernanda Pascutti1, Sjoerd Klarenbeek2, Achia Ait Soussan1, Tom van der Poll4, Mette Hazenberg4, Erfan Nur4, Ellen van der Schoot1, Carlijn Voermans1, Sacha Zeerleder5 P272 DS-2741a, anti-orai1 Antibody, Showed Ideal Profile of Immunosuppressant for GVHD Treatment by Biased Inhibition on Effector T Cells without Affecting Regulatory T Cells Function Masatsugu Oh-hora1, Anri Aki2, Hiroaki Maeda2, Kiyoshi Morimoto2 P273 B-t Cell Interactions in graft-versus-host Disease Dhanya Kizhakayil1, Abbirami Sathappan1, Zoltan Pos2, Nikolett Lupsa2, Christophe M Raynaud1, Giusy Gentilcore1, Mohammad A Al-Aghbar1, Cristina Maccalli1, Jean-Charles Grivel1, Nicholas van Panhuys1, Sara Deola1 P274 Identification of Potential Microbiome Markers for AGVHD Early Diagnosis Dhinoth K Bangarusamy1, Arun P Lakshmanan1, Sara Deola1, Dhanya Kizhakayil1, Zoltan Pos2, Nikolett Lupsa2, Annalisa Terranegra1 P275 Haploidentical Hematopoietic Stem Cell Transplantation with post-transplant Cyclophosphamide for Osteopetrosis Ehud Even-Or, Irina Zaidman, Polina Stepensky P276 Clonal Dynamics and Genomic Integrity of Hematopoietic Stem and Progenitor Cells in Human Allogeneic Transplantation Recipients Flavia Peci1,2, Markus J. van Roosmalen1,2, Rurika Oka1,2, Marc Bierings1, Ruben Boxtel1,2, Mirjam Belderbos1,2 P277 P278 Treatment of Pure Red Cell Aplasia after Major ABO Incompatible Allogenic Stem Cell Transplantation: A French Retrospective Study Thomas Longval1, Jacques-Emmanuel Galimard1, Anne-Claire Leprêtre2, Felipe Suarez3, Denise Amiranoff2, Marine Cazaux1, David Michonneau1, Tereza Coman4, Jean-Henri Bourhis4, Stéphanie Nguyen Quoc5, Eleonore Kaphan1, Gérard Socié1, Régis Peffault de Latour1, Matthieu Resche-Rigon1, Flore Sicre de Fontbrune1 P279 Feasibility and Outcomes of a Third Allogeneic Haematopoetic Stem Cell Transplantation: A Retrospective Analysis from the ALWP of EBMT Andreas Rank1, Christophe Peczynski2, Myriam Labopin2, Matthias Stelljes3, Celestine Simand4, Grzegorz Helbig5, Jürgen Finke6, Stella Santarone7, Johanna Tischer8, Andrzej Lange9, Martin Mistrík10, Mohamed Houhou2, Arnon Nagler11, Christoph Schmid1, Mohamad Mothy12 P280 Changes in Viability Markers of Haematopoietic Stem Cells Following long-term Cryopreservation Lisa O’Connor, Nicola Gardiner, Ashique Khan, Valerie Broderick, Paul Browne, Patrick J. Hayden P281 High pre-transplant Interleukin-18 is associated with Poor Hematopoietic Recovery after Allogeneic Stem Cell Transplantation and Predicts Increased non-relapse Mortality Lambros Kordelas1, Aleksandar Radujkovic2, Hao Dai3, Rashit Bogdanov1, Dietrich W. Beelen1, Carsten Müller-Tidow2, Peter Dreger2, Thomas Luft2 P282 Microbial Diversity, Survival, and Acute GVHD in Adult Recipients of allo-hsct after Myeloablative Conditioning: Results of a Nutritional Intervention Trial Kristin Skaarud1,2, Johannes R. Hov1, Simen H. Hansen1, Martin Kummen1, Asta Bye1,3, Vemund Paulsen1, Knut E. A. Lundin1,2, Marius Trøseid1,2, Geir E. Tjønnfjord1,2, Per O. Iversen1,2 P283 UK Experience in Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) for Activating PI3K Mutations Zohreh Nademi1, Kanchan Rao2, Su Han Lum3, Stephen Jolles4, Colin Steward5, Stephen Hughes6, Robert Wynn6, Winnie Ip2, Austen Worth2, Paul Veys2, Arjan Lankester7, Maria Elena Maccari8, Terry Flood3, Sophie Hambleton1, Andrew Gennery1, Mary Slatter1 P284 Reconstruction of the donor-recipient Haematopoietic Cell Phylogeny Using Somatic Mutations to Establish Numbers of Engrafting long-term HSCS in real-world Transplantation Michael Spencer Chapman1, C. Matthias Wilk2, Steffen Boettcher2, Markus G. Manz2, Peter Campbell1 P285 Successful Clearance of Donor Specific anti-HLA Antibodies after Desensitization with Rituximab, Velcade and plasma-exchange followed by a Haploidentical Stem Cell Transplantion with post-transplantation Cyclophosphamide Sabine Fürst1, Valerio Maisano1, Agnès Basire2, Angela Granata1, Faezeh Legrand1, Raynier Devillier1, Samia Harbi1, Luca Castagna1, Christophe Picard2, Claude Lemarié1, Christian Chabannon1, Didier Blaise1 P286 Impact of pre-transplantation Minimal Residual Disease Determined by Flow Cytometry on Outcome of Acute Leukemia Patients after Allogeneic Stem Cell Transplantation: A Single Center Experience Tangia Muquith1, Michele LM Poon2, Tan Lip Kun2, Koh Liang piu2 P287 Economic Burden of Cytomegalovirus Infection in Allogeneic Hematopoietic Stem Cell Transplant Recipients: A Spanish Multicenter, Retrospective Study Lourdes Vázquez1, Jaime Sanz2, Montserrat Rovira3, Ildefonso Espigado4, Rafael Rojas5, Javier López6, Albert Esquirol7, María Aranzazu Bermúdez8, Rafael De la Cámara9, Raquel Saldaña10, María Inmaculada Heras11, Ana Julia González12, Montserrat Batlle13, Tamara Torrado14, Carlos Vallejo15, Maria Ángeles Cuesta16, Pere Barba17, Santiago Jiménez18, Rafael Francisco Duarte19, Yuexin Tang20, Virginia Lozano21, Stefano Maratia21, Álvaro Muñoz22, Carlos Solano23 P288 Incidence and Outcome of Clonal and Malignant Transformation (CMT) Among Pediatric Patients with Inherited Bone Marrow Failure Syndromes (IBMFSS) Asim Al-Amri, Mouhab Ayas, Amal Al-Seraihy, Abdullah Al-Jefri, Ali Al-Ahmari, Abdulrahman Al-Musa, Mahasen Saleh, Khawar Siddiqui, Ibrahim Ghemlas P289 Impact of post-transplant Immunosuppresion Wean vs. Boost in Early Mixed Chimerism following g-csf-primed Marrow Transplant in Thalassemic Patients Paula Arruda Tacla1,2,3, Rajat Kumar Agarwal4, Rakesh Dhanya4, C P Raghuram2,4, Pallavi Mehta2,4, Deepa Deepa Trivedi4,5, Vaibhav Shah4,5, Priya Marwah6, Rajpreeet Soni6, Sadaf Khalid7, S Sandeep4, Sarah Sarah Khan Gilani6, Aliya Batool7, Lallindra Gooneratne8, Ruwangi Dissanayake8, Fatima Itra9, Tatheer Zahra9, Lawrence Faulkner3,4, Stalin Ramprakash2,4 P290 Validation of Disease Risk Comorbidity Index (DRCI) for Overall Survival after Allogeneic Stem Cell Transplantation (HSCT) With Partially T-cell Depleted GRAFT Yan Beauverd, Sarah Morin, Mitja Nabergoi, Caroline Stephan, Carmen De Ramon Ortiz, Anne-Claire Mamez, Elif Mahne, Anna Petropoulou, Federica Giannotti, Christian Ayer, Benjamin Bruno, Laura Bounaix, Maria Anastasiou, Maria Mappoura, Thien-An Tran, Stavroula Masouridi-Levrat, Yves Chalandon P291 Allogeneic Stem Cell Transplantation in Patients with BCR-ABL-Negative Myeloproliferative Neoplasms Pretreated with JAK1/JAK2 Inhibitors Maria Barabanshikova1, Elena Morozova1, Ivan Moiseev1, Julia Vlasova1, Vadim Baykov1, Inna Ushal2, Gennadij Rodionov2, Sergey Moiseev2, Ildar Barkhatov1, Ksenija Afanasyeva1, Sergey Bondarenko1, Boris Afanasyev1 P292 The Determinative Role of patient-controlled-analgesia (PCA) in the Early Course of Allogeneic Hematopoietic Stem Cell Transplantation Kübra Haşimoğlu, Ferda Can, Oktay Tertemiz, Asena Dikyar, Didem Akçalı, Zübeyde Nur Özkurt, Zeynep Arzu Yeğin P293 High Survival Rate and Low Incidence of AGVHD after CD34+ Stem Cells Selection and CD3+ T Cells Addback in Pediatric MUD HSCT Fulvio Porta1,2, Elena Soncini1, Giulia Carracchia1, Vincenzo Pintabona1, Walter Accini1, Marianna Maffeis1, Rosanna Ceresoli1, Marta Comini1, Alessandra Beghin1, Federica Bolda1, Arnalda Lanfranchi1 P294 Impact of ABO Incompatibility on Outcomes after Haploidentical Hematopoietic Stem Cell Transplantation for Severe Aplastic Anemia Yanru Ma, Wenjing Wang, Lanping Xu, Yu Wang, Xiaohui Zhang, Xiaojun Huang P295 Comparison of Outcomes after Haploidentical Versus Unrelated Donor Hematopoietic Cell Transplantation in Patients with Acute Leukemia: A Retrospective single-center Review Seyed Asadollah Mousavi, Maryam Barkhordar, Tanaz Bahri, Sahar Tavakoli, Leila Mirzakhani, Leyla Sharifi Aliabadi P296 Sequential Conditioning Regimen (Flamsa-bu-mel) in HLA-matched or Haploidentical Hematopoietic Stem Cell Transplantation in Refractory Myeloid Disease Ludovic Jondreville1, Laetitia Souchet2, Françoise Norol2, Madalina Uzunov2, Stéphanie Nguyen2 P297 Investigation of Virological Features and Clinical Outcomes associated with pre-engraftment Cytomegalovirus Dnaemia in Allogeneic Hematopoietic Stem Cell Transplantation Recipients Carlos Solano1,2, Lourdes Vázquez3, Estela Giménez4, Eliseo Albert4, Montserrat Rovira5, Ildelfonso Espigado6, Carmen Martín7, Anabelle Chinea8, Albert Esquirol9, Ariadna Pérez10, Aranzazu Bermúdez11, Rafael De la Cámara12, Raquel Saldaña13, Inmaculada Heras14, Ana Julia González-Huerta15, Tamara Torrado16, Monserrat Batlle17, Santiago Jiménez18, Carlos Vallejo19, Pere Barba20, Maria Ángeles Cuesta21, José Luis Piñana22,23, David Navarro10,24 P298 CD34+ Hematopoietic Progenitor Cell Dose as a Predictor of Engraftment and Survival in Multiple Myeloma Patients undergoing Autologous Stem Cell Transplantation Elifcan Aladag, Haluk Demiroglu, Yahya Buyukasik, Hakan Goker P299 Use of Plerixafor in Poor Mobilizer Patients with Myeloma and Lymphoma: Clonogenic Capacity and Engraftment Data Laura M. Pezzetti1, Giambattista Bertani1, Liliana Intropido1, Tiziana Lamacchia1, Francesca Bosè1, Elisa Zucchetti1, Giovanni Grillo1, Mauro Turrini2, Michela Anghilieri3, Roberto Cairoli1 P300 Outcomes of Haploidentical Stem Cell Transplantation in Pediatrics: A Single Center Experience from India Arun Danewa, Pooja Mallya, Prathip Kumar, Shobha Badiger, Nataraj K S, Sharat Damodar, Vasundhara P K, Ajeitha loganathan, Mohammed Salmaan, Mohan Reddy, Sunil Bhat P301 Pre-emptive Use of Sorafenib Combined with DLI Post HSCT in AML FLT3+: A Single Center Experience Antonella Bruzzese, Giovanni Manfredi Assanto, Daniela Diverio, Maria Stefania De Propris, Silvia Maria Trisolini, Daniela Carmini, Walter Barberi, Luisa Quattrocchi, Mattia Brescini, Giulia Galassi, Ursula Larocca, Anna Paola Iori P302 Use of Eltrombopag for the Management of Poor Graft Function after Hematopoietic Stem Cell Transplantation in Children Maria Luz Uria, Maribel Benitez, Laura Alonso, Maria Oliveras, Berta Renedo, Lucas Moreno, Cristina Diaz de Heredia P303 Treatment of Thrombocytopenia after Allogeneic Stem Cell Transplantation with Eltrombopag Ekin Kircali, Guldane Cengiz Seval, Derya Koyun, Cemaleddin Ozturk, Atilla Uslu, Sinem Civriz Bozdag, Selami Kocak Toprak, Pervin Topcuoglu, Onder Arslan, Muhit Ozcan, Taner Demirer, Hamdi Akan, Osman Ilhan, Gunhan Gurman, Meral Beksac, Meltem Kurt Yuksel P304 Autologous Hematopoietic Stem Cell Transplantion in Multiple Myeloma Irreversibly Depletes Naïve T Lymphocytes Mª Del Pilar Sanz Martín, Yaiza Pérez García, Paula Díaz Fernandez, Víctor López Huete, Lorena Vega Piris, Ana Arteche López, Adrián Alegre Amor, Cecilia Muñoz Calleja P305 Desensitization Protocol in Adult Allogeneic Hematopoietic Stem Cell Transplant Recipients with anti-HLA Donor-specific Antibodies (DSA): A single-center Experience Sara Tricarico1, Federica Alunni2, Rita Tognellini2, Matteo Paradiso1, Adelmo Terenzi1, Antonio Pierini1, Loredana Ruggeri1, Rita Felicini1, Genni Casarola1, Chiara Camerini1, Samanta Bonato1, Mario Griselli1, Andrea Velardi1, Alessandra Carotti1 P306 Association Between Metabolic Alteration with Type and Indication of Hematopoietic Stem Cell Transplantation Claudia Sossa1,2, Ardila-Baez Manuel2, Wandurraga Edwin1,2, Sergio Serrano2, Maria Luna-Gonzalez2, Luis A Salazar1,2, Jimenez Sara I1,2, Manuel Rosales1, Angela M Peña1,2, Xueyi Chen2, Juan J Rey2, Maria A Chacon3 P307 Retrospective Analysis of Survival Outcomes for Patients Receiving Umbilical Cord Blood Transplants at the Royal Marsden Hospital Between 2007 and 2017 Sandra Easdale, Chloe Anthias Anthias, Emma Nicholson, Joy Brennan, Maria Mulligan, Mike Potter, Mark Ethell P308 Higher Cost and no Survival Benefit with Addition of Rituximab to Beam Conditioning for Autologous Transplantation in Patients with Relapsed/Refractory DLBCL Cristian Rodriguez-Arocho, Brandon Blue, Neil Mason, Ariel.F Grajales-Cruz, Franco Garcia, Mahrukh Naqvi, Hanna Bailey, Erjeta Toska, Michael L Nieder, Joseph Pidala, Mohamed Kharfan-Dabaja, Ernesto Ayala, Nelli Bejanyan, Frederick Locke, Asmita Mishra, Hany Elmariah, Farhad Khimani, Taiga Nishihori, Aleksandr Lazaryan P309 Association Between Metabolic Alterations with Age and Gender of Patients with Hematopoietic Stem Cell Transplantation Claudia Sossa1,2, Manuel Ardila-Baez2, Edwin Wandurraga1,2, Sergio Serrano2, Maria Luna-Gonzalez2, Luis A Salazar1,2, Sara I Jimenez1,2, Manuel Rosales1, Angela M Peña1,2, Xueyi Chen2, Juan J Rey2, Maria A Chacon3 P310 Haploidentical HSCT in Children with very high-risk Haematologic Malignancies: A single-centre Experience Sie Chong Doris Lau1,2, Seong Lin Khaw1, Chia Huan Ng1, David Hughes1, Jacqueline Fleming1, Diane Hanna1, Rachel Conyers1, Francoise Mechinaud1 P311 Infused Total Nucleated Cell Dose is not Associated with Engraftment in Autologous Stem Cell Transplantation Francesca Merchionne, Alessandro Spina, Maria Rosaria Coppi, Giuseppe Mele, Giovanni Quintana, Francesco Cucci, Antonella Miccoli, Vincenzo Gatto, Antonio Belardi, Domenico Pastore P312 A Comparison of Allogeneic Stem Cell Transplantation And BFM 95 Chemotherapy Protocol in Adult Patients with Acute Lymphoblastic Leukemia Haluk Demiroglu, Elifcan Aladag, Yahya Buyukasik, Salih Aksu, Hakan Goker P313 Treosulfan Combined with Fludarabine as Conditioning Regimen in Allogeneic Stem Cell Transplanation of Myeloid Diseases, Allows High Overall Survival with Low Related Toxicity Yolanda Gonzalez Romero, Lucrecia Yañez, Miguel Angel Cortes, Andres Insunza, Joan Manuel Mora, Miriam Sanchez-Escamilla, Sara Fernandez-Luis, David Gomez-Lamas, Jose Calvo-Sanchez, Sergio Fernandez-Garcia, Guillermo Martin-Sanchez, Mercedes Colorado, Enrique Ocio, Aranzazu Bermudez P314 Outome of Relapsed Acute Lymphoblastic Leukemia in Children and Adolescents Post Allogeneic Hematopoietic Stem Cell Transplantation Zofia Szmit, Anna Król, Krzysztof Kałwak, Marek Ussowicz, Małgorzata Salamonowicz-Bodzioch, Jowita Frączkiewicz, Monika Mielcarek-Siedziuk, Justyna Miśkiewicz-Bujna, Izabella Miśkiewicz-Migoń, Ewa Gorczyńska P315 Motivation for Antifungal use in Pediatric HSCT Patients in an Institution in Southern Brazil Fernanda Fetter Scherer1, Lisandra Della Costa Rigoni1, Adriano Nori Taniguchi1, Mariana Monteiro Burin1, Cristiane Seganfredo Weber1, Dayenne Helena Catelli1, Marina de Almeida Furnaletto1, Tahiane de Brum Soares1, Sheila Nogueira do Amaral1, Priscila de Oliveira da Silva1, Fernanda Chede Leifer Nunes1, Daniela Dias Morales1, Karla Rodrigues Silveira2, Mariana Bohns Michalowski2, Lucia Mariano da Rocha Silla2, Alessandra Aparecida Paz1, Liane Esteves Daudt2 P316 Impact of the Use of Granulocytic colony-stimulating Factor after Allogeneic Hematopoietic Stem Cell Transplantation Inés Martínez Alfonzo1, Laura Solan Blanco1, Javier Cornago Navascues1, Begoña Pérez de Camino Gaisse1, Clara Cuellar Pérez-Ávila2, Ana Lerma Verdejo3, Aida Franganillo Suárez1, Teresa Arquero Portero1, José Luis López Lorenzo1, Pilar Llamas Sillero1 P317 P318 Phase II Study of Plerixaflor and G-CSF as Mobilizing Therapy for Double Autologous Transplantation Patients with Relapsedrefractory Diffuse Large B Cell, Pet Positive after Two R-DHAP Vincenzo Pavone1, Anna Mele1, Eleonora Prete1, Giuseppe Milone2, Giulio Milone1, Stefania Citiso1, Antonino Greco1, Nicola Di Renzo3, Annarita Messa3, Pasquale Forese3, Giuseppina Greco1, Silvia Sibilla1, Maria Rosaria Morciano1, Patrizio Mazza4, Giovanni Pisapia4, Giulia Palazzo4, Rosa De Francesco1, Clara De Risi1, Lorenzo Tonialini1, Francesco Gaudio5, Tommasina Perrone5, Pellegrino Musto6, Giorgina Specchia5 P319 The Effect of CD34+ Hematopoietic Progenitor Cell Dose on the Hematopoietic Recovery and Survival in Acute Lymphoblastic Leukemia (ALL) Patients Underwent Allogeneic Stem Cell Transplantation Elifcan Aladag, Haluk Demiroglu, Yahya Buyukasik, Salih Aksu, Hakan Goker P320 The Eventual Role of Donor and Recipient Vitamin D Levels in Allogeneic Hematopoetic Stem Cell Transplant Setting Asena Dikyar, Erhan Hocaoğlu, Lale Aydın Kaynar, Zübeyde Nur Özkurt, Zeynep Arzu Yeğin P321 Average Length of Hospital Stay for Pediatric Blood and Marrow Transplants in the Backdrop of Cell Source, Transplant Type and Outcome Amal Al-Seraihy, Khawar Siddiqui, Rafat Jafri, Antonette Amao, Hawazen Alsaedi, Abdullah Aljefri, Ali Alahmari, Ibrahim Ghemlas, Awatif Alanazi, Mouhab Ayas P322 One Center Experience in Offline Technique Validation with Biological Quality Tests María Liz Paciello Coronel, Alejandra Leivas Aldea, Sara Redondo Velao, Encarnación Güemes Arce, Yolanda Paredes, Patricia Pérez Tomás, Mercedes Hernández, Borja Andrades Velazquez, Desire Sánchez Lozano, Maria Nieves Elvira Cortaberria, Consuelo Carralero, Joaquín Martínez López P323 The Outcome of Allotransplant using TBF Conditioning from Matched Sibling Related Donors in High Risk Myelodysplasia and Acute Myelid Leukemia: A Retrospective Single Center Experience Khalid Halahleh, Waleed Da’ana, Husam Abu-jazar, Mohamad Ma’koseh, Salwa Saadeh, Rozan AL Far, Abdelghani Tbakhi P324 Efficacy and Safety of Post Hematopoietic Stem Cell Transplantation Donor Lymphocyte Infusion in Patients with Acute Leukemia. Retrospective Analysis in Our Center Yolanda Gonzalez Romero1, Joan Manuel Mora1, Miguel Angel Cortes1, Sara Fernandez-Luis1, David Gomez-Lamas1, Aranzazu Bermudez1, Andres Insunza1, Lucrecia Yañez1, Cristina Amunarriz2, Mercedes Colorado1, Enrique Ocio1, Guillermo Martin-Sanchez1 P325 Cardiovascular Risk in Patients before and after Hematopoietic Stem Cell Transplantation Claudia Sossa1,2, Manuel Ardila-Baez2, Edwin Wandurraga1,2, Sergio Serrano2, Maria Luna-Gonzalez2, Luis A Salazar1,2, Sara I Jimenez1,2, Manuel Rosales1, Angela M Peña1,2, Xueyi Chen2, Juan J Rey2, Maria A Chacon3 P326 Peripheral Blood Stem Cell Transplantation in Pediatric Recipients in Peru: Experience of a Referral Center Essy Maradiegue, Sharon Chávez P327 Haematopoietic Stem Cell Product Viability: A Comparative Study Between Bags and Vials Nadia Tanya Glatt, Colwyn Poole, Bibi Rhode, Matlhodi Moalosi, Khensani Mathye P328 Transfusion Support in the First 30 and 100 Days after Haploidentical versus HLA-matched Related Donor Hematopoietic Stem Cell Transplantation Mireia Santos Gómez1, Agueda Ancochea Serra2, Eva Alonso Nogués2, Joan Ramon Grifols Ronda2, Mireia Morgades de la Fe1, Mireia Franch Sarto1, Georgina Gener Ricós1, Christelle Ferrà Coll1, Susana Vives Polo1, Anna Torrent Catarineu1, Miriam Moreno Velázquez1, Montserrat Batlle Massana1, Blanca Xicoy Cirici1, Laura Abril Sabater1, Gladys Ibarra Fernández1, Alicia Senín Magán1, Albert Oriol Rocafiguera1, Josep Maria Ribera Santasusana1, Juan Manuel Sancho Cia1 P329 Haploidentical Hematopoitec Stem Cell Trasplantation with Macs in a Peruvian Health Childrens Institute: three-year Experience Sergio Murillo-Vizcarra1, Karina Rojas-Fernandez1, Carolina Benavides-Vallve2, Karina Pinto-Gossin2, Carlos Vidurrizaga-De Amezaga2 P330 Collection, Cryopreservation and Autologous Transplantation of Peripheral Blood Stem Cells in Kaunas, Lithuania 2015-2019 Ieva Golubickaite1, Birute Sabaniene1, Inga Valanciute1, Elona Juozaityte2, Rolandas Gerbutavicius2, Domas Vaitiekus2, Aurija Kalasauskiene2, Diana Remeikiene2, Jonas Surkus2, Ruta Leksiene2, Milda Rudzianskiene2, Martyna Beitneriene2, Vilma Svetickiene1, Ruta Dambrauskiene2, Vaida Didziariekiene2, Daiva Urboniene2, Dietger Niederwieser3 P331 Evaluation of Overall Survival in Allogeneic Hematopoietic Stem Cell Transplantation (ALLOHSCT). Unicentric Experience Begoña perez de camino gaisse1, Javier Cornago Navascués1, Ana Lerma Verdejo2, Clara Cuellar Pérez-Ávila3, José Luis Lopez Lorenzo1, Pilar Llamas Sillero1 P332 Refractory T-cell Cutaneous Lymphoma Treated with Allogeneic Haploidentic Hematopoietic Stem Cell Transplantation- A Case Report Marcia Silva, Natalia Laso, Maria Claudia Moreira, Simone Lermontov, Rita De Cassia Barbosa, Simone Maradei, Marta Colares, Yung Gonzaga, Leonardo Arcuri, Renato Araujo, Decio Lerner P333 Autologous Stem Cell Transplantation: A single-center Experience Over Last Years Rocío Zapata Bautista, María Solé Rodríguez, Antonio J. Palma Vallellano, Encarnación Gil Espárraga, Bianca Díaz Roldán, Francisco Fernández Moreno P334 Causes of Complications in Adults during the First Year after Allogeneic Hematopoietic Stem Cell Transplantation Bosco Martin McNally Guillen, Brenda Lizeth Acosta Maldonado, Liliana Mey Rivera Fong, José Manuel Téllez Araujo, Oyuky Gissell Aguirre Reyes, José Luis Estrada Rico, Alejandra Mendoza Torres, Luis Manuel Valero Saldaña P335 High Dose Stem Cell Therapies, Like MGTA-456, Enable Complete Neural and Peripheral Disease cross-correction Through Rapid and Robust Hematopoietic Engraftment Kevin Goncalves, Sharon Hyzy, Melissa Brooks, Hans Hertzler, Anthony Boitano, Michael Cooke P336 HLA set-up is a major Predictor of Engraftment in haplo-identical Transplant for Severe Thalassemia (ST) using post-cyclophosphamide (PTCY) Stalin Ramprakash1,2, C P Raghuram1,3, Pallavi Mehta4, Paula Tacia1,2, Priya Mawah4, Rajpreet Soni4, Deepa Trivedi5, Vaibhav Shah5, Rakesh Dhanya2, Rajat Kumar Agarwal2, Lawrence Faulkner2,7 P337 Lentiglobin Gene Therapy Treatment of Two Patients with Transfusion-dependent β-thalassemia Mattia Algeri1, Richard A. Colvin2, Weijian Liu2, Ge Tao2, Franco Locatelli1 P338 Bone Marrow Transplant in Patients with Sickle Cell Anaemia. Experience in One Centre Marina García Morín, Laura Escobar Fernández, Eduardo Bardón Cancho, Cristina Beléndez Bieler, Jorge Huerta Aragonés, Carmen Garrido Colino, Cristina Mata Fernández, Elena Cela de Julián P339 Outcomes in Cerebral Adrenoleukodystrophy after Hematopoietic Stem Cell Transplantation: Single Center Experience Koray Yalcin1, Gulsun Karasu1, Vedat Uygun2, Suar Caki Kilic1, Seda Ozturkmen2, Suna Celen1, Hayriye Daloglu2, Dayanat Pashayev1, Fugen Pekun1, Volkan Hazar1, Akif Yesilipek1 P340 Neurodevelopmental Outcomes of Hematopoietic Stem Cell Transplantation for Mucopolysaccharidosis Type II: A Prospective, Longitudinal Study Maria Escolar1,2, Nicholas Bascou1,2, Bridget Kiely1,2, Aleksandra Safonova1,2, Maria Beltran1,2, Michele Poe1,2, Paul Szabolcs1,2 P341 Hematopoietic Stem Cell Transplantation for Sickle Cell Disease: The Spanish Experience Maria Isabel Benítez Carabante1, Cristina Beléndez2, Marta González Vicent3, Jose Luis Fuster4, Luz Uria1, Laura Alonso1, Isabel Badell5, Jose María Pérez Hurtado6, Elena Cela2, Cristina Díaz de Heredia1,7 P342 Long-term Quality of Life in Patients with Thalassemia Major following Hematopoetic Stem Cell Transplantation in Childhood Oruc Ali Quliyev, Gulcihan Ozek, Savas Kansoy, Serap Aksoylar P343 High Incidence of Autoimmune Cytopenias after Allogeneic Stem Cell Transplantation in Pediatric Patients with Thalassemia and Sickle Cell Disease: The Impact of Matched Unrelated Donor Christina Oikonomopoulou, Anna Paisiou, Eleni-Dikaia Ioannidou, Aikaterini Kaisari, Anna Komitopoulou, Maria Theodosaki, Eftichia Petrakou, Ioulia Peristeri, George Vessalas, Evgenios Goussetis, Vassiliki Kitra-Roussou P344 P345 A Phase II Stratified Trial to Assess Haploidentical t-depleted Stem Cell Transplantation in Patients with Sickle Cell Disease with no Available Sibling Donor Jürgen Föll1, Katharina Kleinschmidt1, Anja Tröger1, Petra Turowski1, Rainer Spachtholz1, Norbert Ahrens1, Andreas-Michael Brosig1, Matthias Evert1, René Schmidt2, Daniel Wolff1, Matthias Edinger1, Matthias Eyrich3, Rupert Handgretinger4, Susanne Ellinger1, Selim Corbacioglu1 P346 Hematopoietic Stem Cell Transplantation for Inborn Errors of Metabolism using Alternate Donors: A Prospective Single Study Rashin Mohseni, Maryam Behfar, Alieh Safari-Sharari, Fahimeh Jafari, Zeynab Nikfetrat, Leila Hejazipour, Hamideh Keykani, Pouria Salajegheh, Amir Ali Hamidieh P347 Pearson Syndrome in a Patient Transplanted for diamond-blackfan Anemia Gülsün Karasu1,2, Vedat Uygun1,3, Hayriye Daloğlu3, Seda Öztürkmen3, Akif Yeşilipek3 P348 Haploidentical Stem Cell Transplantation for Class 3 Thalassemia major using post-transplant Cyclophosphamide Eman Khattab, Rula Najjar, Abdelghani Tbakhi, Rawad Rihani, Mayada Abu Shanap, Hasan Hashem, Aram Ahmod, Nilly Hussein, Iyad Sultan P349 Hematopoietic Stem Cell Transplantation for Severe Combined Immunodeficiency in Japan: A Nationwide Retrospective Analysis Satoshi Miyamoto1,2, Masakatsu Yanagimachi1,2, Katsutsugu Umeda2,3, Akihiro Iguchi2,4, Yoji Sasahara2,5, Hidetoshi Takada2,6, Yoshiyuki Takahashi7, Michiko Kajiwara1, Masami Inoue8, Koji Kato9, Yoshiko Hashii10, Yoshiko Atsuta11, Hiromasa Yabe2,12, Kohsuke Imai1,2, Tomohiro Morio1,2 P350 Immunodeficiency - Centromeric Instability - Facial Dysmorphism (ICF) Syndrome: Evaluation of Characteristics and Outcome after Allogeneic Hematopoietic Stem Cell Transplantation Dagmar Berghuis1, Lisanne van Leeuwen1, Jorinde Hoogenboom2, Corry Weemaes3, Mary Slatter4,5, Reem Elfeky6, Michael Albert7, Roland Meisel8, Alexandra Laberko9, Akif Yesilipek10, Lubna Mehyar11, Andrew Gennery4,5, Arjan Lankester1 P351 Thiotepa versus Melphalan Containing Conditioning Regimens in Hematopoietic Stem Cell Transplantations with TCRαβ/CD19 Graft Depletion for Primary Immunodeficiencies Alexandra Laberko, Elvira Sultanova, Yulia Skvortsova, Irina Shipitsina, Svetlana Kozlovskaya, Svetlana Radygina, Anna Livshits, Aishat Kantulaeva, Elena Kurnikova, Anna Shcherbina, Alexei Maschan, Michael Maschan, Dmitry Balashov P352 Improved Transplant Survival and Long-term Disease Outcome for Children with CD40 Ligand Deficiency Su Han Lum1, Sahar Habibollah1, Peter McNaughton1, Zohreh Nademi1, Terry Flood1, Andrew Cant1, Mario Abinun2, Sophie Hambleton1,2, Mary Slatter1,2, Andrew Gennery1,2 P353 Hematopoietic Stem Cell Transplantation Outcomes Including Immune Reconstitution in Primary Immunodeficiencies: 5 Years of Single Centre Experience Yasmina Mozo1, Luz Yadira Bravo1,2, Juan Manuel Torres1,2, David Bueno1, Luisa Sisinni1, Teresa Del Rosal1, Ana Méndez1, Luis Ignacio Gonzalez-Granado3,4, Raquel De Paz1, Berta González1, Sonsoles San Román1, Andreina Figueira1, Víctor Galán1, María Coronel1,2, Carla Gianelli1,2, Rebeca Rodríguez Pena1,2, Elena Sánchez Zapardiel1,2, Eduardo López Granados1,2, Antonio Pérez Martínez1,5 P354 Outcomes of Stem Cell Transplant for RIPK1 Deficiency: Single Centre Experience Peter McNaughton1, Su Han Lum1, Zohreh Nademi1, Terry Flood1, Eleri Williams1, Andrew Cant1, Mario Abinun1, Andrew R Gennery1,2, Sophie Hambleton1,2, Mary Slatter1,2, Stephen Owens1,2 P355 Improving the Result of Hematopoietic Stem Cell Transplantation For Primary Immunodeficiency with Serious Infection in Developing Countries using Ric Regiment Maryam Behfar1, Mahnaz Jamee1,2, Armin Khavandegar1,2, Alieh Safari-Sharari1, Rashin Mohseni1, Fahimeh Jafari1, Zeynab Nikfetrat1, Leila Hejazipour1, Hamideh Keykani1, Amir Ali Hamidieh1 P356 Single-center Experience of Haploidentical Hematopoietic Stem Cell Transplantation With TCR αβ Depletion in Children with Primary Immunodeficiency Syndromes Didem Atay1, Arzu Akcay1, Fatma Demir Yenigurbuz1, Burcu Akinci1, Meral Akbiyik2, Ercument Ovali1, Gulyuz Ozturk1 P357 Haplo-identical Transplant Using post-transplant Cyclophosphamide (PTCY) in Children with Severe Combined Immunodeficiency - A Tertiary Care Centre Experience from South India Stalin Ramprakash1, C P Raghuram1, Chetan Ginigeri1, Fulvio Porta2, Sagar Bhattad1 P358 Necrotizing Enterocolitis in a two-month-old Scid Patient after Bone Marrow Transfusion - Surgical Intervention At Day +1: Yes or No? Laura M. Moser, Stefan Gfroerer, Roland Schrewe, Shahrzad Bakhtiar, Julia Fekadu, Eva Rettinger, Jan Soerensen, André Willasch, Peter Bader, Andrea Jarisch P359 Long-term Enzyme Replacement Therapy (ERT) in ada-scid Patients: The Shadow of Malignancies Fulvio Porta1,2, Lucia Dora Notarangelo1, Elena Soncini1, Giulia Carracchia1, Vincenzo Pintabona1, Elisa Bertoni1, Walter Accini1, Marta Comini1, Alessandra Beghin3, Federica Bolda1, Arnalda Lanfranchi1 P360 Haematopoietic Stem Cell Transplantation for X-linked Agammaglobulinaemia Complicated by Chronic Norovirus Enteropathy Ben Shillitoe1, Mark Ponsford2, Mary Slatter1, Stephen Jolles2,3, Andrew Gennery1,4 P361 Hematopoetic Stem Cell Transplantation in CD40 Ligand Deficiency Vedat Uygun1, Dilara Fatma Kocacık Uygun2, Hayriye Daloğlu3, Seda Öztürkmen3, Suar Çakı Kılıç4, Ayşen Bingöl2, Koray Yalçın4, Safiye Suna Çelen4, Volkan Hazar4, Gülsün Karasu1, Akif Yeşilipek3 P362 Allogeneic Hemotopoietic Stem Cell Transplantation (HSCT) for Chronic Granulomatous Disease (CGD) in Childhood Anna Paissiou, Elda Ioannidou, Marianna Tzanoudaki, Christina Oikonomopoulou, Katerina Kaisari, Anna Komitopoulou, Kleopatra Spanou, Ioulia Peristeri, Niki Konstantinidou, Eugenios Gousetis, George Vessalas, Vassiliki Kitra P363 Risk of Infectious Complications in Adult Patients After Allogeneic HSCT Depending on The Site of Central Venous Catheter Insertion - Multicentre Prospective Study Emilian Snarski1, Jacqui Stringer2, Małgorzata Mikulska3,4, Lidia Gil5, Gloria Tidello6, Paul Bosman7, Jennifer Hoek7, Michal Karas8, Samo Zver9, Catherina Lueck10, Nicole Blijlevens11, Iria González12, Małgorzata Ociepa-Wasilkowska13, Michał Górka14, Isabel Sánchez-Ortega15, Inger Andersson16, Lucrecia Yáñez17, Mohamed Amine Bekadja18, Jan Styczyński19 P364 Infection Prevention Practices among EBMT Hematopoietic Cell Transplant Centers: A Survey of The Infectious Diseases Working Party of the EBMT Moshe Yeshurun1,2, Uri Rozovski1,2, Liat Shargian1,2, Oren Pasvolsky1,2, Diana Averbuch3, Steffie van der Werf4, Nina Knelange5, Malgorzata Mikulska6, Jan Styczynski7 P365 HEV Infection In HCT Recipients - Retrospective Study of Infectious Diseases Working Party (IDWP) of EBMT Malgorzata Mikulska1, Olaf Penack2, Lotus Wendel3, Nina Knelange3, J.J. Cornelissen4, Nicole Blijlevens5, Jakob Passweg6, Nicolaus Kroger7, Anke Bruns8, Arnold Ganser9, Marc Bierings10, Helen Labussière-Wallet11, Gilles Salles12, Jan Styczynski13 P366 The Role of Combination Prophylaxis in Preventing Cytomegalovirus (CMV) Infection after Ex Vivo Ab t-cell-depleted Haploidentical Hematopoietic Cell Transplant (HHCT) in Children Sung Han Kang1, Jae Won Yoo2, Jin Kyung Seo1, Hyery Kim1, Kyung-Nam Ko1, Eun Seok Choi1, Seongsoo Jang1, Chan-Jeoung Park1, Jong Jin Seo1, Ho Joon Im1 P367 Comparison of Immune Cell Response to Cytomegalovirus Proteins Versus Peptides using an IFN-γ Elispot Assay to Monitor cytomegalovirus-specific Immunity after Hematopoietic Stem Cell Transplantation Eva Wagner1, Daniel Teschner1, Christine Wolschke2, Dietlinde Janson2, Kerstin Schäfer-Eckart3, Johannes Gärtner3, Stephan Mielke4,5, Martin Schreder5,6, Guido Kobbe7, Mustafa Kondakci7, Inken Hilgendorf8, Marie von Lilienfeld-Toal8, Stefan Klein9, Daniela Heidenreich9, Sebastian Kreil9, Mareike Verbeek10, Sandra Grass10, Markus Ditschkowski11, Tanja Gromke11, Martina Koch1,2, Monika Lindemann11, Thomas Hünig5, Traudel Schmidt12, Anne Rascle12, Harald Guldan12, Sascha Barabas12, Ludwig Deml12, Ralf Wagner12,13, Daniel Wolff13 P368 Human Herpesvirus Type 6 Reactivation after Haploidentical Hematopoietic Cell Transplantation: Risk Factors and Clinical Impact Tânia Maia1,2, Annalisa Paviglianiti1, Florent Malard1,3,4, Eolia Brissot1,3,4, Giorgia Battipaglia1,4, Clémence Médiavilla1,4, Anne Banet1, Zoé Van de Wyngaert1, Tounes Ledraa1, Ramdane Belhocine1, Simona Sestili1, Rosa Adaeva1, Simona Lapusan1, Agnès Bonin1, Anne Vekhoff1, Ollivier Legrand1,3,4, Mohamad Mohty1,3,4, Rémy Duléry1,3,4 P369 Safety and Efficacy of Brincidofovir for Refractory Adenovirus Infection in Children Receiving Allogeneic SCT: A Retrospective Analyses from The Italian Pediatric Hematology Oncology Association (AIEOP) Katia Perruccio1, Mariacristina Menconi2, Federica Galaverna3, Daria Pagliara3, Francesca Carraro4, Franca Fagioli4, Elisabetta Calore5, Alessandra Biffi5, Valentina Baretta6, Maria Speranza Massei7, Maura Faraci8, Marta Verna9, Elena Soncini10, Maurizio Caniglia7, Franco Locatelli3, Simone Cesaro6 P370 Subcutaneous Immunoglobulin Replacement Therapy in Patients who underwent Allogeneic Hematopoietic Cell Transplantation (HCT): A Prospective Study to Measure Feasibility, Safety and Health Care Resource Use Ivan Pasic1, Wael Alanazi1, George Dranitsaris2, Lani Lieberman3, Auro Viswabandya1, Dennis D. Kim1, Jeffrey H. Lipton1, Fotios V. Michelis1 P371 Infectious Complications in Patients with Relapsed/refractory Hodgkin’s Lymphoma after New Agents’ Therapy and Allogeneic Stem Cell Transplantation Yuliya Rogacheva, Marina Popova, Kirill Lepik, Yurii Zalylov, Lilia Stelmakh, Alisa Volkova, Iliya Nikolaev, Anastasiia Beinarovich, Olga Pirogova, Evgeniya Borzenkova, Oleg Goloshchapov, Sergey Bondarenko, Ivan Moiseev, Vadim Baykov, Nataliya Mikhailova, Nikolay Klimko, Boris Afanasyev P372 Surveillance For Reactivation of Toxoplasma Gondii using Polymerase Chain Reaction Assay and pre-emptive Therapy Avoids Universal Prophylaxis and Prevents Symptomatic Infection Mariam Amer, Deborah S. Richardson, Christopher Dalley, Kate S. Hill, Sara Main, Helen Snow, Amy Creighton, Nikki Mckeag, Joan Newman, Linda Jarvis, Sarah Holtby, Kim H. Orchard P373 Cytomegalovirus (CMV) Impact on Clinical Outcomes and Resource use after Allogeneic Hematopoietic Cell Transplantation: The Influence of Recurrent Episodes of CMV Infection Carlos de Miguel1, Ana Royuela1,2, María Francisca Portero1, Juan Luis Cruz1,3, María Esther Martínez-Muñoz1, María Isabel Sánchez1, Guiomar Bautista1, Rafael Cabrera1, Rafael Francisco Duarte1 P374 Fecal Microbiota Transplantation in Children to Treat Acute GVHD or multi-drug Resistant Bacteria Colonization Pietro Merli1, Federica Galaverna1, Marco Becilli1, Mattia Algeri1, Stefania Gaspari1, Francesco Quagliarella1, Roberto Carta1, Luisa Strocchio1, Simona Faraci1, Federica Del Chierico1, Giuseppe Palumbo1, Luca Masucci2, Lorenza Putignani1, Annalisa Ruggeri1, Franco Locatelli1,3 P375 Vaccination Against Tick-borne Encephalitis (TBE) after Autologous and Allogeneic Bone Marrow Transplantation Sigrun Einarsdottir1, Malin Nicklasson1, Malin Veje2, Tomas Bergström3, Per Ljungman4, Berit Johansson5, Mikael Olsson6, Björn Andreasson7, Marie Studahl8, Benedicte Piauger1, Anette Roth3, Mats Brune1 P376 Rifaximin use Favoured Micafungin Resistant Candida SPP Infections in Recipients of Allogeneic Hematopoietic Cell Transplantation Francesca Marzuttini1, Matteo Paradiso1, Samanta Bonato1, Mario Griselli1, Sara Tricarico1, Chiara Camerini1, Genni Casarola1, Emanuele Venturini1, Antonella Mancusi1, Anna Maria Tortorano2, Rita Felicini1, Tiziana Zei1, Roberta Iacucci1, Loredana Ruggeri1, Franca Falzetti1, Adelmo Terenzi1, Lucia Pitzurra1, Alessandra Carotti1, Andrea Velardi1, Antonio Pierini1 P377 Baseline Characteristics and early poly-functional Assessment of T Cells to Identify Patients at Higher Risk to Develop Severe HCMV Reactivation after Allogeneic HSCT Elisa Gabanti1, Oscar Borsani2, Daniela Caldera1, Anna Amelia Colombo1, Virginia Ferretti1, Emilio Paolo Alessandrino1, Paolo Bernasconi1,2, Daniele Lilleri1 P378 Impact of HHV-6 Reactivation After T-reg/T-con Immunotherapy in Allogeneic Transplantation: A single-center Retrospective Study Chiara Camerini, Alessandra Carotti, Loredana Ruggeri, Adelmo Terenzi, Franca Falzetti, Silvia Bozza, Roberto Castronari, Samanta Bonato, Genni Casarola1, Rita Felicini, Mario Griselli, Francesca Marzuttini, Matteo Paradiso, Sara Tricarico, Antonella Mencacci, Andrea Velardi, Antonio Pierini P379 Adenovirus Infections after HCT: Infectious Diseases Working Party Retrospective EBMT Registry Study Jan Styczynski1, Gloria Tridello2, Nina Knelange3, Joan Hendrik Veelken4, Gerard Socie5, Stephan Mielke6, Benedicte Neven7, John A. Snowden8, Jean-Hugues Dalle9, Marie Thérèse Rubio10, Charles Crawley11, Johan Maertens12, Jurgen Kuball13, Patrice Chevallier14, Gérard Michel15, Peter J. Shaw16, Ram Malladi17, Robert F. Wynn18, Yves Bertrand19, Nicole Blijlevens20, Charlotte Jubert21, Tobias Gedde-Dahl22, Ibrahim Yakoub-Agha23, Maija Itäla-Remes24, Lidia Gil25, Simone Cesaro2, Malgorzata Mikulska26 P380 Clinical Impact of Colonization by Multidrug-resistant Enterobacteriaceae in Allogeneic Hematopoietic Stem Cell Transplantation Sara Fernández-Luis, David Gómez Lamas, Juan Manuel Martín Cerezo, Juan José Domínguez García, Claudia González-Rico, Lucrecia Yáñez, Joan Manuel Mora Barrios, Yolanda González Romero, Rocío Lobeira Rubio, Jose Álvaro Calvo Sánchez, Sergio Fernández García, Mónica López-Duarte, Mercedes Colorado, Guillermo Martín Sánchez, Enrique Ocio, María Carmen Fariñas, Arancha Bermúdez P381 Post-allogeneic Transplantation Progressive Multifocal Leukoencephalopathy, Clinical and Biological Features, Treatment and Outcomes: A Retrospective Study from the SFGM-TC Alexis Genthon1, Sylvain Chantepie2, Amandine Le Bourgeois3, Jacques Olivier Bay4, Marie-Thérèse Rubio5, Ali Bazarbachi6, Stephanie Nguyen7, Yves Beguin8, Xavier Poiré9, Amandine Charbonnier10, Nathalie Fegueux11, Michaël Loschi12, Micha Srour13, EOLIA Brissot14 P382 Efficacy of Letermovir for Prophylaxis of CMV Reactivation after Allogeneic Hematopoietic Cell Transplantation: A Multi Center Retrospective Analysis among Japanese Patients Yasuo Mori1, Goichi Yoshimoto1, Tetsuya Eto2, Koji Nagafuji3, Hiromi Iwasaki4, Yoshikiyo Ito5, Yuju Ohno6, Tomohiko Kamimura7, Ryosuke Ogawa8, Akihiko Numata1, Koji Kato1, Katsuto Takenaka1,9, Toshihiro Miyamoto1, Koichi Akashi1 P383 Standardized Monitoring of cytomegalovirus-specific Cellular Immunity can Improve Risk Stratification of Recurrent Cytomegalovirus Reactivation after Hematopoietic Stem Cell Transplantation Eva Wagner1, Daniel Teschner1, Christine Wolschke2, Dietlinde Janson2, Kerstin Schäfer-Eckart3, Johannes Gärtner3, Stephan Mielke4,5, Martin Schreder5,6, Guido Kobbe7, Mustafa Kondakci7, Inken Hilgendorf8, Marie von Lilienfeld-Toal8, Stefan Klein9, Daniela Heidenreich9, Sebastian Kreil9, Mareike Verbeek10, Sandra Grass10, Markus Ditschkowski11, Tanja Gromke11, Martina Koch1,2, Monika Lindemann11, Thomas Hünig5, Traudel Schmidt12, Anne Rascle12, Harald Guldan12, Sascha Barabas12, Ludwig Deml12, Ralf Wagner12,13, Daniel Wolff13 P384 Impact of Levofloxacin for Prophylaxis of Pre-engraftment Bloodstream Infections after Allogeneic HSCT: A single-center Matched Analysis in an Endemic Country for Carbapenem-resistant Gram-negative Bacteria Daniela Clerici1, Chiara Oltolini1, Raffaella Greco1, Federico Erbella1,2, Rosamaria Nitti1,2, Marco Ripa1,2, Fabio Giglio1, Sara Mastaglio1, Francesca Lorentino1, Francesca Farina1, Carmine Liberatore1,2, Barbara Castiglioni1, Chiara Tassan Din1, Massimo Bernardi1, Jacopo Peccatori1, Consuelo Corti1, Paolo Scarpellini1, Antonella Castagna1,2, Fabio Ciceri1,2 P385 Progressive Multifocal Leukoencephalopathy (PML) after HCT - A Retrospective Study of Infectious Diseases working Party EBMT Jaroslaw Dybko1, Lidia Gil2, Lotus Wendel3, Nina Knelange3, Nicoalus Kröger4, Amjad Hayat5, Maria Liga6, Nicole Blijlevens7, Ali Bazarbachi8, Maura Faraci9, Ganser Arnold10, Maximilian Steinhardt11, Bernd Gruhn12, Maria Stamouli13, Sara Villar14, Jakob Passweg15, Rik Schots16, Paolo Bernasconi17, Tsila Zuckerman18, Malgorzata Mikulska19, Jan Styczynski20 P386 Oral Ribavirin is a Highly Efficacious Treatment for Lower Respiratory Tract Infection due to Respiratory Syncytial or Parainfluenza Virus in Allogeneic Stem Cell Transplant Recipients Ioannis Tsonis1, Ioannis Baltadakis1, Maria Stamouli2, Konstantinos Gkirkas2, Christina Economopoulou3, Dimitra Gardeli1, Thomas Thomopoulos2, Anna Paisiou3, Dimitra Oikonomopoulou1, Tatiana Tzenou1, Nikolaos Siafakas2, Spyridon Pournaras2, Anastasia Antoniadou2, Aggeliki Karagiannidi2, Eirini Grispou1, Joseph Meletiadis2, Dimitra Kavatha2, Stavros Gigantes2, Evgenios Goussetis3, Dimitrios Karakasis1, Panagiotis Tsirigotis2 P387 Timing of Induction Treatment for Reactivation of Cytomegalovirus Impacts Overall Survival in Pediatric Allogeneic Hematopoietic Cell Transplant Christine Camacho-Bydume, Irene Rodriguez-Sanchez, Audrey Mauguen, Genovefa Papanicolaou, Susan Prockop, Elizabeth Klein, Nancy Kernan, Jaap-Jan Boelen, Maria Cancio P388 Prediction of Bloodstream Infection Risk using Citrulline as Biomarker of Intestinal Mucositis in hemato-oncology Patients Charlotte de Mooij, Walter van der Velden, Antonius de Haan, Lenneke van Groningen, Nicole Blijlevens P389 Prediction of CMV Reactivation by the Recipient IGG Titer Before allo-HCT Shunto Kawamura1, Hideki Nakasone1, Shun-Ichi Kimura1, Masakatsu Kawamura1, Junko Takeshita1, Nozomu Yoshino1, Yukiko Misaki1, Kazuki Yoshimura1, Shinpei Matsumi1, Ayumi Gomyo1, Yu Akahoshi1, Masaharu Tamaki1, Machiko Kusuda1, Hidenori Wada1, Koji Kawamura1, Aki Tanihara1, Shinichi Kako1, Yoshinobu Kanda1,2 P390 Comparison of Infectious Complications among Patients Receiving Unmanipulated Haploidentical Transplant followed by Post-transplant Cyclophosphamide and Selective Ex Vivo T-cell Depleted Haploidentical Transplant Louis-Pierre Girard1, Yin Jie Koh2, Xin Liu2, Davanaliz Gonzales Ramos2, Teck Guan Soh2,3, Lip Kun Tan2,3, Michelle LM Poon2, Lionel Lum3, Liang Piu Koh2 P391 The Cumulative Incidence of Multiple DNA Virus Reactivation is not Different in Non-depleted Haploidentical Stem Cell Transplantation and Unrelated Allogeneic Stem Cell Transplantation Mariana Nassif Kerbauy1, Andreza Alice Feitosa Ribeiro1, Lucila Nassif Kerbauy1, Cinthya Correa da Silva1, Nelson Hamerschlak1, Clarisse Martins Machado1,2 P392 Neutrophils Response to Human CMV Reactivation in Allogeneic Hematopoietic Stem Cell Transplant Recipients Martina Costa, Nicola Tamassia, Marco Ligozzi, Olivia Marini, Marco Cassatella, Cristina Tecchio P393 Clinical Efficacy of Letermovir Prophylaxis for CMV Infection after Allogeneic Hematopoietic Stem Cell Transplantation: A Single Center Experience Atsushi Satake, Jun Ichikawa, Ryo Saito, Akiko Konishi, Masaaki Hotta, Takahisa Nakanishi, Aya Nakaya, Shinya Fujita, Tomoki Ito, Kazuyoshi Ishii, Shosaku Nomura P394 At-home Foscarnet Administration in Allogeneic Hematopoietic Transplantantation Patients with Cytomegalovirus Infection: A Safety Feasible Model Alexandra Pedraza, Gonzalo Gutierrez, Cristina Gallego, Esther Carcelero, Marta Prat, Maria Suarez-Lledo, Gerardo Rodriguez-Lobato, Alexandra Martínez, Carmen Martínez, Laura Rosiñol, Montse Rovira, Alvaro Urbano-Ispízua, Francesc Fernandez P395 Effects of the Antibiotics Change or the Addition of Anti-mrsa Drugs for Persistent Febrile Neutropenia after Autologous Stem Cell Transplantation Nozomu Yoshino, Koji Kawamura, Masakatu Kawamura, Syunto Kawamura, Junko Takeshita, Yukiko Misaki, Kazuki Yoshimura, Shinpei Matsumi, Ayumi Gomyo, Yu Akahoshi, Masaharu Tamaki, Machiko Kusuda, Kazuaki Kameda, Hidenori Wada, Hideki Nakasone, Shinichi Kako, Yoshinobu Kanda P396 Therapeutic Drug Monitoring of Posaconazole and Subsequent Dosing in Allogeneic Hematopoietic Stem Cell Transplant Patients Mateja Kraljevic1, Nina Khanna1, Michael Medinger1, Jakob Passweg1, Yves Chalandon2, Stavroula Masouridi-Levrat2, Nicolas Mueller3, Urs Schanz3, Chistian Van Delden2, Dionysios Neofytos2 P397 Prophylaxis with Azithromycin in Allogeneic Cord Blood Transplant and Association with Relapse Rate and Transplant Outcomes José Miguel Mateos Pérez, José Ramon Álamo Moreno, Carlos De Miguel Jiménez, Clara González Santillana, Alonso Trillo Rosalia, Sara Garrido Paniagua, Ángela Benéitez Fernández, Lucía Núñez Martín-Buitrago, Ana Bocanegra Pérez-Vizcaíno, Marta Liébana Villela, Ana Alarcón Tomás, María Esther Martínez, Ana Fernandez-Cruz, Guiomar Bautista Carrascosa, José Rafael Cabrera Marín, Antonio Ramos Marínez, Rafael F. Duarte P398 Reactivated Varicella Zoster (VZV) Infection (Shingles), after Haematopoietic Stem Cell Transplant (HCT) for Haematological Disease in Children: A Significant Problem and Proposal for Future Management Dafydd Stonehewer, Joanne Ellis, Tasneem Khalid, Stephen Hughes, Robert Wynn P399 Letermovir Prophylaxis Reduces Inpatient Resource Consumption by Being Effective in Preventing Cytomegalovirus Reactivation after Allogeneic Hematopoietic Cell Transplantation: A Single Center real-world Experience Patrick Derigs, Maria-Luisa Schubert, Paul Schnitzler, Tilman Schöning, Carsten Müller-Tidow, Thomas Luft, Peter Dreger, Michael Schmitt P400 Analysis of CMV Reactivation Risk after T Cell Replete Haploidentical and Matched Donor Allogeneic Hematopoietic Cell Transplantation Barbora Čemusová1, Petr Hubáček2, Veronika Válková1, Marketa Marková1, Ludmila Nováková1, Mariana Koubová1, Petr Cetkovský1, Jan Vydra1 P401 Incidence and Impact of Epstein-barr Virus Events in the Early Phase after Allogeneic Hematopoietic Stem Cell Transplantation Samuel Macy, Nina Khanna, Hans Hirsch, Dominik Heim, Claudia Lengerke, Dimitrios Tsakiris, Jakob Passweg, Michael Medinger P402 Aspergillus Non-fumigatus Invasive Aspergillosis in Children and Adults after Hematopoietic Stem Cell Transplantation (HSCT) & Chemotherapy Marina Popova1, Yuliya Rogacheva1, Alexander Siniaev1, Alisa Volkova1, Inna Markova1, Alexander Shvetcov1, Ilya Nikolaev1, Olga Pinegina1, Svetlana Ignatieva2, Tatiyana Bogomolova2, Asmik Gevorgian1, Olesya Paina1, Tatiyana Bykova1, Elena Darskaya1, Oleg Goloshchapov1, Mariya Vladovskaya1, Sergey Bondarenko1, Ivan Moiseev1, Ludmila Zubarovskaya1, Nicolay Klimko1,2, Boris Afanasyev1 P403 Intravenous Pentamidine for Pneumocystis Jirovecii prophylaxis in Hematological Patients Treated with Chemotherapy, Hematopoietic Stem-cell Transplant (HSCT) and car-t Cell Therapy Nieves López Muñoz, Elena Vera Guerrero, Marta Hidalgo Soto, María Calbacho, Jose María Sánchez Pina, Joaquín Martínez-López P404 Intensification of CMV Prophylaxis with the use of Ganciclovir during the Conditioning in Haploidentical Transplantation with post-transplantation Cyclophosphamide. Comparison with a Standard Strategy. 113 Patients Amado Karduss, Angela Trujillo, Angelica Cardona, Rosendo Perez, Giovanni Ruiz, Gloria Suarez P405 Prophylactic Dose Trimethoprim/sulfamethoxazole Does not Lead to Delayed Neutrophil and Platelet Engraftment in Allogeneic Haematopoetic Stem Cell Transplant Recipients Rachael Biggart1, Sarah Bird1, Chloe Anthias1,2, Sandra Easdale1, Michael Potter1, Joy Brennan1, Maria Mulligan1, Emma Thistlethywaite1, Kim Davis1, Mark Ethell1, Unell Riley1, Emma Nicholson1 P406 High Dose Valaciclovir as CMV Prophylaxis in Allogeneic Haematopoietic Stem Cell Transplantation Genevieve Douglas1,2, Michelle Yong2,3,4, Shioyen Tio2,3,4, Maggie Chau2, Joe Sasadeusz2, Monica Slavin2,3,4, David Ritchie1,2,4, Lynette Chee1,2 P407 Invasive Mold Disease in a Real-world Hemato-oncology Setting: Value of a Diagnostic-driven Care Pathway Elizabeth de Kort, Walter van der Velden, Paul Verweij, Nicole Blijlevens P408 Single Center Analysis on the Management of Acyclovir Resistant Herpes Simplex Virus Stomatitis in Patients after Allogeneic Hematopoietic Cell Transplantation Daniela Heidenreich, Sebastian Kreil, Nadine Mueller, Mohamad Jawhar, Florian Nolte, Wolf-Karsten Hofmann, Stefan A. Klein P409 Early Bacteremia following Allogeneic Bone Marrow Transplantation without the use of Prophylactic Antibiotic: Changing Epidemiology and Antimicrobial Resistance (2016-2018) Nour Ben Abdeljelil, Rihab Ouerghi, Dorra Belloumi, Amel Lakhal, Lamia Torjemane, Rym El Fatmi, Wafa Achour, Saloua Ladeb, Tarek Ben Othman P410 Diagnostic Yield of Bronchoalveolar Lavage (BAL) in Haematological Patients after Allogeneic/Autologous Hematopoietic Stem Cell Transplantation (HSCT) - Comparison with BAL Performance in non-transplanted Patients Martina Palackova1, Iva Kocmanova2, Martina Lengerova1,2, Helena Svabova1,2, Frantisek Folber1,2, Jiri Mayer1,2, Zdenek Racil1 P411 Versatile Effects of Letermovir Prophylaxis for Cytomegalovirus on Allogeneic Hematopoietic Stem Cell Transplantation: A single-institution Analysis Fumiaki Jinnouchi, Yuta Katayama, Ryota Imanaka, Tatsuya Terasaki, Takuya Nunomura, Takeshi Okatani, Kohei Kyo, Mitsuhiro Itagaki, Shinya Katsutani, Tsuyoshi Muta, Hideki Asaoku, Koji Iwato P412 Impact of a Change in Antibacterial Prophylaxis in Patients Receiving Autologous Stem Cell Transplantation in One Single Center María Solé Rodríguez, Rocío Zapata Bautista, Antonio José Palma Vallellano, Encarnación Gil Espárraga P413 Intravescical Instillation of Cidovofir is Efficient for the Treatment of BK Virus Hemorrhagic Cystitis after Allogeneic Transplantation Maria Liga1, Nikolaos Spyridis1, Evgenia Verigou1, Charalambia Korovila1, Kalliopi Lekka1, Evi Triantafyllou1, Alexandra Siorenta2, Markos Marangos1, Alexandros Spyridonidis1 P414 Risk Factors and Outcome of Early Clostridium Difficile Infection in Acute Leukemia Patients undergoing Allogeneic Hematopoietic Stem Cell Transplantation Chiara Rosignoli, Vera Radici, Rossella Stella, Alessandra Sperotto, Antonella Geromin, Marta Lisa Battista, Michela Cerno, Renato Fanin P415 Risk Factors for Cytomegalovirus Infection in Children Undergoing Hematopoietic Stem Cell Transplantation Bernd Gruhn, Pania Mokthari P416 Impact of Hypogammaglobulinemia on Outcome of Allogeneic Hematopoietic Stem Cell Transplantation in Adult Acute Lymphoblastic Leukemia Patients Salvatore Leotta, Uros Markovic, Alessandra Cupri, Giuseppe Sapienza, Luca Scalise, Maria Cristina Pirosa, Enrica Antonia Martino, Angelo Curto Pelle, Giulio Antonio Milone, Maria Grazia Camuglia, Anna Lia Di Marco, Annalisa Condorelli, Giovanni Schininà, Roberta Sciortino, Andrea Spadaro, Giuseppe Milone P417 The use of Rifaximine in anti-bacterial Prophylaxis in Patient undergoing HSCT Magdalena Dutka, Agata Szymańska, Patryk Sobieralski, Maria Bieniaszewska P418 Risk Factors for CMV Reactivation and Disease Among Hematopoietic Stem Cell Transplant Recipients - Defining the Target Population for Letermovir Prophylaxis Thao Ngyuen, Jennifer Kaivers, Ortwin Adams, Nadine Lübke, Thomas Schroeder, Christina Rautenberg, Ben-Niklas Bärmann, Thomas Ulrych, Rainer Haas, Jörg Timm, Mustafa Kondakci, Guido Kobbe P419 Isavuconazole (ISA) use in Adult Allogeneic Hematopoietic Stem Cell Transplant (ALLO-HSCT) Recipients: A single-center Experience Sara Tricarico1, Adelmo Terenzi1, Antonio Pierini1, Loredana Ruggeri1, Rita Felicini1, Genni Casarola1, Chiara Camerini1, Matteo Paradiso1, Samanta Bonato1, Mario Griselli1, Bianca Maria Goffredo2, Andrea Velardi1, Alessandra Carotti1 P420 Time- and therapy-dependent Bacteriuria in Children and Young Adults Following Allogeneic HSCT Alexey Chukhlovin, Anna Spiridonova, Maria Vladovskaya, Ilya Kazantsev, Asmik Gevorgian, Tatyana Bykova, Ludmila Zubarovskaya, Boris Afanasyev P421 Phase 3 Randomized, double-blind Study of Maribavir Compared with Valganciclovir for Treatment of Cytomegalovirus (CMV) Infection in Hematopoietic stem-cell Transplant (HSCT) Recipients (Study Design) Johan Maertens1, Sophie Alain2, Robin Avery3, Rose Ann Murray4, Jingyang Wu4, Per Ljungman5 P422 Incidence and Risk Factors of Viral Complications in Adult Patients undergoing Allogeneic Stem Cell Transplantation - A single-center Experience From Hungary Balint Gergely Szabo1,2, Eszter Szabo1, Melinda Paksi1, Eszter Sari1, Eva Torbagyi1, Apor Hardi1, Aniko Barta1, Laszlo Gopcsa1, Janos Sinko1, Peter Remenyi1 P423 Unicentric Study: Prophylaxis Strategy against GVHD with post-transplant Cyclophosphamide (CPYT) and its Relationship with Cytomegalovirus Ana Lerma Verdejo1, Clara Cuéllar Pérez-Ávila2, Begoña Pérez de Camino Gaisse3, Javier Cornago Navascués3 P424 Epidemiology and Clinical Features of Febrile Neutropenic Episodes: Three Years Experience at Hematology Wards Huseyin Saffet Bekoz, Zeynep kaya, Ali Mert P425 Toxoplasmosis Disease after allo-HSCT. What have we Learnt? Laura Escobar Fernandez, Marina García Morín, Eduardo Bardón Cancho, Jorge Huerta Aragonés, Cristina Beléndez Bieler, Elena Rincón López, María Slocker Barrio, Elena Cela de Julián P426 Tuberculosis in Patients Who receive an Allogeneic Hematopoietic Stem Cell Transplant. Two Case Report Haridian de la Nuez Melián, Melissa Torres Ochando, Leslie González Pinedo, Santiago Jiménez Bravo de Laguna, Maria Del Mar Perera Alvárez, Paula Fernández-Caldas González, Leonor Pérez Ortiz, Joan Gonzálvez Fernández, Asunción Borrero Borrego, Juan Francisco López Rodríguez, Luisa Guerra Domínguez, Teresa Molero Labarta P427 Polyomavirus BK Infection in Bone Marrow Transplantation Recipients. A Comparative Analysis on Children and Adults Cristian Jinca1, Andrada Oprisoni1, Anca Isac2, Andreea Pascalau2, Margit Serban2, Andrei Munteanu2, Smaranda Arghirescu1 P428 Leflunomide, Successful pre-emptive Therapy in Resistant Cytomegalovirus Reactivation in a Hematopoietic Cell Transplantation Recipient Gloria Elena Mora, Maria Jose Lopez Mora, Enrique Pedraza, Herman Esguerra, Javier Figueroa, Oscar Peña, Sergio Ardila, Angie Guarin, Diego Orlando Diaz, Licet Villamizar, Cesar Lamadrid, Gustavo Adolfo Lopez P429 Letermovir as Pre-emptive Therapy for Resistant Cytomegalovirus Infection after Allogeneic Stem Cell Transplantation Paula María García Cereijo1, Tamara Torrado Chedas1, Agustín Nieto Vázquez1, Raquel Iglesias Varela2 P430 Infectious Complications in Hematologic Patients with Hematopoietic Stem Cell Transplantation Vitalii Chebotkevich, Alena Kuleshova, Anastasia Zhernyakova, Catherine Kiseleva, Sergey Gritsaev, Stanislav Bessmeltsev P431 CMV Retinitis in a Stem Cell Transplant Recipient Treated with Foscarnet Intravitreal Injection and CMV Specific Immunoglobulin Francesco Vassallo, Alessandro Busca, Chiara Della Casa, Lucia Brunello, Luisa Giaccone, Sara Butera, Giorgia Iovino, Francesco Giuseppe De Rosa, Raffaele Nuzzi, Ilaria Cattani, Benedetto Bruno P432 Efficacy and Safety of Donor Lymphocyte Infusions for Patients affected by Advanced Lymphoid Malignancies after Allogeneic Stem Cell Transplantation: A Retrospective Study Elisa Diral1,2, Raynier Devillier3, Sabine Furst3, Angela Granata3, Stefania Bramanti4, Samia Harbi3, Jacopo Mariotti4, Chiara De Philippis4, Barbara Sarina4, Thomas Pagliardini3, Valerio Maisano3, Rocco Piazza2, Reda Bouabdallah3, Carmelo Carlo-Stella4, Armando Santoro4, Didier Blaise3, Luca Castagna3 P433 Brentuximab-vedotin in Combination with Bendamustine as Salvage Therapy Prior Hematopoietic Stem Cell Transplantation for Patients with Hodgkin Lymphoma: Real-world Data from a Two Centers Study Panayotis Kaloyannidis1, Hani Al Hashmi1, Ahmad Al Saeed2, Ahmed Absi2, Eshrak Al Shaibani1, Jennifer Bacal1, Muted Al Thumali2, Ihab El Hemaid2, Sammer Alamoud2, Mohammed Al Darweesh1, Enas Mutahar1, Majed Alahmad2, Walaa Rajkha2, Manar Khali2, Ioannis Apostolidis1, Saleem Eldad2, Khalid Al Anezi1 P434 Impact of Kir Ligand Mismatch after Allogeneic Hematopoietic Stem Cell Transplantation for Hodgkin Lymphoma: A Retrospective Study in 383 Patients from the SFGM-TC Jean-Edouard Martin1, Stéphane Morisset2, Regis Peffault De La Tour3, Nathalie Fegueux4, Edouard Forcade5, Sylvie François6, Jean-Baptiste Mear7, Patrice Chevallier8, Eric Deconink9, Hélène Labussière-Wallet10, Claude-Eric Bulabois11, Jacques-Olivier Bay12, Mohamad Mohty13, Marie-Thérèse Rubio14, Didier Blaise15, Stéphanie Nguyen1 P435 The Impact and Challenges of Performing Beam Conditioned Autologous Transplants in ‘older’ Patients with Lymphoma David Davies1, Keith Wilson1,2, Sarah Doherty1, Emma Kempshall1, Hamdi Sati3, Wendy Ingram1 P436 Allogeneic Hematopoietic Stem Cell Transplantation in Transformed Follicular Lymphoma (FL): Results from A Retrospective Multicenter Study From Gelth/geltamo Group Beatriz Rey Búa1, Mónica Cabrero1,2, Leyre Bento3, Miriam López-Parra1,2, Juan Montoro4, Nieves Dorado5, Mariana Bastos5, Gonzalo Gutiérrez-García6, Oriana López Godino7, Lucrecia Yañez8, Lucía López Corral1,2, Laura Prieto2, Marta Fonseca1, Silvana Novelli9, Christelle Ferrà10, Pilar Herrera11, Carlos Grande12, Joud Zanabili13, Isabel Sánchez-Ortega14, Rocio Parody14, Alejandro Martín1,2, M.Dolores Caballero1,2 P437 Allogeneic Hematopoietic Stem Cell Transplantation for Follicular Lymphoma Relapsing after Autologous Transplantation Masatoshi Sakurai1, Takehiko Mori1, Souichi Shiratori2, Toshio Wakayama3, Naoyuki Uchida4, Hikaru Kobayashi5, Junya Kanda6, Takahiro Fukuda7, Yoshiko Atsuta8,9, Eisei Kondo10 P438 Significant Role of Upfront Autologous Stem Cell Transplantation in Patients with High Risk Diffuse Large B-cell Lymphoma Dae Sik Kim1, Sung-Hoon Jung2, Deok-Hwan Yang2, Youngil Koh3, Junshik Hong3, Ho-Young Yhim4, Won Sik Lee5, Yoo Jin Lee6, Jeong-Ok Lee7, Hye Jin Kang8, Sung Yong Oh9, Yun-Suk Choi6, Ho Sup Lee10, Jung-Hee Lee11, Yong Park12, Byung Bae Park13, Young Rok Do14, Ho-Jin Shin15 P439 Autologous Stem Cell Transplantation in HIV+ and HIV- Lymphoma Patients: A Propensity Score Matched Analysis Margherita Oberti1,2, Alessandro Re1, Chiara Cattaneo1, Nicola Bianchetti1, Chiara Pagani1, Armando Stabile3, Salvatore Casari4, Emanuele Foca’5, Camillo Almici1, Dino Veneri2, Fabio Benedetti2, Francesco Castelli5, Mauro Krampera2, Giuseppe Rossi1 P440 Allogeneic Stem Cell Transplantation can be Successfully Delivered Following BTKI Therapy Failure Following R-bac Re-induction Chemotherapy in Patients with Mantle Cell Lymphoma David Lewis1, Rory McCulloch1, Toby Eyre2, David Tucker3, Nimish Shah4, Deborah Turner5, Oliver Miles6, Nicola Crosbie1, Simon Rule1 P441 Clinical Outcomes of EBV+ PTLD Patients Following HCT who Fail Rituximab: A Retrospective Chart Review Study from France Gérard Socié1, Arnaud Pigneux2, Charles Herbaux3, Paul Chauvet3, Hairong Xu4, Dhanalakshmi Thirumalai4, Norma Guzman-Becerra4, Arie Barlev5, John Reitan6, Mohamad Mohty7 P442 The Impact of Allogeneic Hematopoietic Cell Transplantation (ALLOHCT) on the Outcome of poor-risk Non-hodgkin Lymphoma (NHL): Update of a Retrospective intent-to-transplant (ITT) Analysis Lorenz Selberg, Peter Stadtherr, Sascha Dietrich, Thomas Luft, Ute Hegenbart, Andrea Bondong, Julia Meissner, Nora Liebers, Michael Schmitt, Carsten Müller-Tidow, Peter Dreger P443 Comparison of Mitoxantrone - Melphalan and Beam Conditioning Regimens in Lymphoma Patients Ahmet Kursad Gunes1, Ilknur Demir2, Serpil Sarifakioglu2, Salih Sertac Durusoy2, Dervis Murat Akkurt2, Idris Ince3, Gulkan Ozkan4, Mustafa Pehlivan2 P444 Nivolumab re-challenge in Patients with Relapsed/refractory Classical Hodgkin Lymphoma: Where is the Place for Allohsct? Liudmila Fedorova1, Kirill Lepik1, Natalia Mikhailova1, Elena Kondakova1, Yuri Zalyalov1, Vadim Baykov1, Elena Babenko1, Evgeniya Borzenkova1, Lilia Stelmakh1, Boris Afanasyev1 P445 Outcome of Transplant Eligible Mantle Cell Lymphoma Patients with first-line Regimens in a real-world Setting - A Portuguese Multicenter Retrospective Analysis Pedro Chorão1, Teresa Ribeiro2, Maria Gomes Silva3, Raquel Guilherme4, Filipa Saraiva5, Joana Vieira6, Inês Carvalhais1, Sérgio Chacim2, José Mário Mariz2, Daniela Coelho4, Marília Gomes4, Manuela Mafra7, Mariana Leal Fernandes5, Ana Mata6, Daniela Alves6, Fernando Príncipe1 P446 Evaluation of Fractionated Ice as an Alternative Outpatient Option for Relapsed/refractory Lymphomas Reyad Dada1,2, Ehab Abdelghany1, Tarek Boubakr1, Emily Lenore Goldman-Heaphy1, Azhar Nawaz1 P447 Efficacy of Haploidentical Stem Cell Transplantation for Patients with Relapsed/refractory Classical Hodgkin Lymphoma Anastasiya Beynarovich, Kirill Lepik, Natalia Mikhailova, Elena Kondakova, Yurii Zalyalov, Eugenia Borzenkova, Elena Babenko, Elena Darskaya, Alexander Aliynskiy, Ivan Moiseev, Boris Afanasyev P448 Risk Factors for Intensive Care Unit Admission in Patients with Non-hodgkin Lymphoma Undergoing Autologous Stem Cell Transplantation Laura Posada Alcón, Helena Díez Zubia, Xabier Martín Martitegui, María Elena Amutio Diez, Juan Carlos García Ruiz P449 Autologous Stem Cell Transplantation after Nivolumab Treatment for Patients with Relapsed/refractory Primary Mediastinal B-cell Lymphoma Olesya Smykova, Kirill Lepik, Natalia Mikhailova, Andrey Kozlov, Elena Kondakova, Yuri Zalyalov, Lilia Stelmakh, Boris Afanasyev P450 The Irish Experience of Thiotepa, Carmustine and Etoposide Conditioning Prior to ASCT for the Treatment of Central Nervous System Lymphomas Ashique Khan1, Carmel Waldron1, Elizabeth Higgins1, Richard Flavin1, Greg Lee1, John Quinn2, Liam Grogan2, Deidre O’Mahony3, Rajnish Gupta4, Larry Bacon1, Elizabeth Vandenberghe1 P451 Allogeneic Hematopoietic Cell Transplantation as Treatment Option for Rare Transdifferentiation of Lymphoid Neoplasms into Histiocytic and Dendritic Cell Neoplasms to Achieve Long-term Survival Andriyana Bankova1,2, Urs Schanz2, Eugenia Haralambieva2, Ewerton Maggio2, Corinne Widmer2 P452 Outcome of Allogeneic Hematopoietic Cell Transplantation for Patients with Peripheral T Cell Lymphomas: A Retrospective Analysis from the Polish Lymphoma Research Group (PLRG) Malgorzata Sobczyk-Kruszelnicka1, Tomasz Czerw1, Joanna Drozd-Sokołowska2, Patrycja Mensah-Glanowska3, Agnieszka Piekarska4, Anna Łojko-Dankowska5, Anna Czyż6, Sebastian Giebel1 P453 Treatment Outcome of Primary Mediastinal B Cell Lymphoma after High Dose Chemotherapy with Autologous Hematopoietic Cell Transplantation. A Study of The Polish Lymphoma Research Group Joanna Romejko-Jarosinska1, Ewa Paszkiewicz-Kozik1, Małgorzata Krawczyk-Kulis2, Patrycja Mensah-Glanowska3, Lukasz Targonski1, Agnieszka Giza3, Tomasz Czerw2, Katarzyna Domanska-Czyz1, Kseniya Kviatkouskaya3, Paulina Magda3, Wlodzimierz Mentrek2, Beata Ostrowska1, Maria Sadus-Wojciechowska2, Sebastian Giebel2, Jan Walewski1 P454 Place of Hematopoietic Stem Cell Transplantation in Patients with T-cell Lymphomas: Pavlov University Experience Elena Lepik1, Andrey Kozlov1, Evgenia Borzenkova1, Yuri Zalyalov1, Kirill Lepik1, Elena Kondakova1, Vadim Baykov1, Aleksander Alyanskiy1, Ivan Moiseev1, Tatiana Schneider2, Natalia Mikhaylova1, Boris Afanasyev1 P455 Autologous Hematopoietic Stem Cell Transplantation for Diffuse Large B-cell Lymphoma: Toxicity and Survival Study Khouloud Touihri, Rym El fatmi, Lamia Torjemane, Dorra Belloumi, Nour Ben abdeljelil, Amel Lakhal, Saloua Ladeb, Tarek Ben othman P456 Autologous Hematopoietic Stem Cell Transplantation for HIV-related Lymphoma Elisabetta Terruzzi1, Elisa Diral2, Matteo Parma1, Marilena Fedele1, Luisa Verga1, Giovanni Zambrotta2, Andrea Aroldi2, Pietro Pioltelli1, Carlo Gambacorti Passerini1,2 P457 Allogeneic Hematopoietic Stem Cell Transplantation for Relapsed and Refractory Hodgkin Lymphoma: A Retrospective single-center Analysis of 23 Patients Dariusz Kata, Agata Wieczorkiewicz-Kabut, Grzegorz Helbig, Małgorzata Kopera, Aleksandra Zimnoch, Kamil Witosz P458 Autologous Stem Cell Transplant in a Seropositive a Patient with Plasmablastic Lymphoma (PBL) Fahad Shaikh, Reetu Jain, Samir shah, Ganapathi Bhat P459 CMV Infection is Associated with Reduced Thymic Function and Less Regulatory T Cells after Pediatric Allogeneic HSCT Katrine Kielsen1, Dina Leth Møller1, Anders Elm Pedersen2, Marianne Ifversen1, Claus H. Nielsen1, Lars P. Ryder1, Klaus Müller1,2 P460 Impact of Pre-transplant MRD Burden Measured by Multicolor Flow Cytometry on Relapse and Survival in AML Patients undergoing allo-SCT in CR Evgeny Klyuchnikov, Maximilian Christopeit, Anita Badbaran, Ute-Marie von Pein, Urike Fritzsche-Friedland, Christine Wolschke, Nicolaus Kröger P461 Flow-based Pre-transplant MRD Detection Strongly Impacts on the Outcome of Haploidentical Transplantation with AB T Cell Depletion in Pediatric Acute Lymphoblastic Leukemia Larisa Shelikhova, M Ilyushina, A Popov, Z Shekhovtsova, D Balashov, A Kazachenok, I Muzalevsky, I Shipitsina, D Shasheleva, S Kozlovskaya, R Khismatullina, E Kurnikova, J Abugova, A Bogoyavlenskaya, S Blagov, Y Skvortsova, D Pershin, D Kobyzeva, A Nechesnyuk, N Myakova, D Litvinov, G Novichkova, A Maschan, M Maschan P462 CMV-specific T Cell Counts Early after Allogeneic Hematopoietic Stem Cell Transplantation Stratify the Risk of Subsequent CMV Reactivations: Results of a Prospective Observational Study Maddalena Noviello1, Elena Tassi1, Pantaleo De Simone1, Francesca Serio1, Maria Teresa Lupo-Stanghellini1, Giacomo Oliveira1, Sara Racca1, Roee Dvir1, Lorenzo Lazzari1, Daniela Clerici1, Fabio Giglio1, Francesca Lorentino1, Consuelo Corti1, Massimo Bernardi1, Liselotte Brix2, Fabio Ciceri1,3, Jacopo Peccatori1, Raffaella Greco1, Chiara Bonini1,3 P463 Improved Relapse-free-survival in Patients with High Natural Killer Cell Doses in Grafts and during Early Immune Reconstitution after Allogeneic Transplantation with Peripheral Blood Stem Cells Lia Minculescu1, Anne Fischer-Nielsen1, Eva Haastrup1, Lars Peter Ryder1, Niels Smedegaard Andersen1, Ida Schjoedt1, Lone Smidstrup Friis1, Brian Thomas Kornblit1, Søren Lykke Petersen1, Hanne Vibeke Marquart1, Henrik Sengelov1,2 P464 Potential Influence of Immunodeficiency-related Hereditary Predisposition Gene Variants on Relapse after Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Hematological Malignancies Zhihui Li, Tong Wu, Qinglong Zheng, Caiyan Zhang, Yongqiang Zhao, Yanzhi Song P465 P466 Impact of Residual Circulating Tumor DNA Status Post Allogeneic SCT in Patients with Acute Myeloid Leukemia and Myelodysplastic Syndromes: Interim Results of a Prospective Study Miho Ogawa1, Kazuaki Yokoyama1, Hiroto Ishii2, Takayoshi Tachibana3, Taisei Suzuki3, Kiyoshi Okazuka4, Yuri Tamura5, Takuya Miyazaki6, Chikako Ohwada7, Mai Mizusawa8, Kensuke Usuki8, Heiwa Kanamori3, Chiaki Nakaseko9, Tatsuki Tomikawa10, Yu Akahoshi11, Yuhei Nagao5, Shokichi Tsukamoto7, Masahiro Takeuchi7, Emiko Sakaida7, Makoto Onizuka12, Susumu Tanoue2, Shingo Yano2, Satoko Osanai13, Akihito Shinohara13, Junji Tanaka13, Sachiko Seo14, Nobuyuki Aotsuka15, Nobuhiro Tsukada4, Shin Fujisawa16, Nozomi Yusa1, Kanya Kondoh1, Tomomi Takei1, Sousuke Nakamura1, Mika Ito1, Rika Kasajima1, Mako Yamamoto1, Eigo Shimizu1, Masamichi Isobe1, Takaaki Konuma1, Seiko Kato1, Rui Yamaguchi17, Seiya Imoto1, Satoshi Takahashi1, Satoru Miyano1, Arinobu Tojo1, Shinichiro Okamoto18 P467 Pattern of Reconstitution of Recent Thymic Emigrants after Reduced Intensity Conditioning Based on Targeted Busulfan in Paediatric Recipients of Allogeneic Haematopoetic Stem Cell Transplantation Daniel Drozdov1,2, Katrin Petermann3, Leonhard Held3, Tayfun Güngör1, Mathias Hauri-Hohl1 P468 A Risk Score System Based on Post-transplantation Minimal Residual Disease for Stratification of Relapse in B-ALL Patients after Allogenic Stem Cell Transplantation Yang Zhou1, Le-Qing Cao1, Yan-Rong Liu1, Lan-Ping Xu1, Xiao-Hui Zhang1, Yu Wang1, Huan Chen1, Yu-Hong Chen1, Feng-Rong Wang1, Wei Han1, Yu-Qian Sun1, Chen-Hua Yan1, Fei-Fei Tang1, Xiao-Dong Mo1, Kai-Yan Liu1, Qiao-Zhen Fan1, Ying-Jun Chang1, Xiao-Jun Huang1,2,3 P469 Outcome of Children with Hematological Malignancies who Develop Mixed Donor Chimersim after Allogeneic Hematopoietic Stem Cell Transplantation Amit Dotan1,2, Danna Zevy2, Kuang-Yueh Chiang2,3, Tal Schechter-Finkelstein2,3, Muhammed Ali2,3, Joerg Krueger2,3 P470 Prophylactic high-dose Donor CD45RO+ Memory T-cells Infusion after Allogeneic Transplantation: Safety and Outcome Mercedes Gasior Kabat1, Luisa Sisinni1, Raquel De Paz1, David Bueno1, Yasmina Mozo1, Beatriz De La Cruz1, Antonio Marcos1, Ana Belen Romero1, Victor Jimenez Yuste1, Antonio Pérez-Martínez1,2 P471 Multicolor Flow Cytometry Panel with CCD79A Gating to Detect Minimal Residual Disease in Patients with B-lymphoblastic Leukemia/lymphoma Post Anti-CD19 Car-t Therapy Bridging to allo-HSCT Man Chen1, Aixian Wang2, Minjing Fu1, Xueying Wu2, Junyi Zhen2, Meiwei Gong2, Hui Wang2 P472 Non-invasive Monitoring of Minimal Residual Disease and graft-versus-host Disease By Circulating cell-free Nucleic Acids after Allogeneic Hematopoietic Cell Transplantation Miguel Waterhouse, Sandra Patricia Pennisi, Dietmar Pfeifer, Justus Duyster, Hartmut Bertz, Jürgen Finke, Jesus Duque-Afonso P473 Torque Teno Virus as Biomarker to Predict Complications and Outcome after Allogeneic Hematopoietic Stem Cell Transplantation Amandine Pradier, Stavroula Masouridi-Levrat, Carine Bosshard, Carole Dantin, Diem-Lan Vu, Marie-Céline Zanella, Elsa Boely, Caroline Tapparel, Laurent Kaiser, Yves Chalandon, Federico Simonetta, Eddy Roosnek P474 Preemptive Interferon-α Treatment Could Protect against Relapse and Improve Survival of Acute Lymphoblastic Leukemia Patients after Allogeneic Hematopoietic Stem Cell Transplantation Si-Ning Liu1, Xue-Yi Luo1, Xiao-Hui Zhang1, Lan-Ping Xu1, Yu Wang1, Chen-Hua Yan1, Huan Chen1, Yu-Hong Chen1, Kai-Yan Liu1, Xiao-Jun Huang1,2, Xiao-Dong Mo1 P475 A New Multivariate Model to Describe Impact of Immune Reconstitution on the Development of Relapse in Children undergoing allo-HSCT for Hematologic Malignancies at Day +100 Manuela Spadea1,2, Francesco Saglio1,2, Massimo Berger1,2, Francesca Carraro1,2, Rosanna Pessolano1,2, Emanuela Ricotti1,2, Elena Ernestina Vassallo1,2, Franca Fagioli1,2 P476 Acquisition of Complete Chimerism in Bone Marrow, Peripheral Blood and Leukocyte Subsets Depends on the Transplant Setting and Correlates with the Clinical Outcome Almudena Navarro-Bailon1, Diego Carbonell1,2, Julia Suárez-González1,2, María Chicano1,2, Mi Kwon1,2, Rebeca Bailén1,2, Nieves Dorado1,2, José Luis Díez-Martín1,2,3, Carolina Martínez-Laperche1,2, Ismael Buño1,2,3 P477 Early Lymphoid Subsets Reconstitution after Allogeneic Haematopoietic Stem Cell Transplantation (HSCT) as Predictor of Relapse and Survival in Acute Leukemias Riccardo Boncompagni, Arianna Fani, Ilaria Cutini, Gaia Ciolli, Chiara Innocenti, Massimo Di Gioia, Serena Mariotti, Agata Suellen Guarrera, Giulia Raugei, Antonella Gozzini, Chiara Nozzoli, Stefano Guidi, Riccardo Saccardi P478 Comparison of Immune Reconstitution Between 30Mg/kg and 60Mg/kg Anti-T-lymphocyte Globuline (ATLG) as Graft versus Host Disease Prophylaxis after Allogeneic Myeloablative Peripheral Blood Stem Cell Transplantation Radwan Massoud, Martina Güllstorf, Christine Wolschke, Max Christopeit, Boris Fehse, Petra Freiberger, Francis Ayuk, Nicolaus Kröger P479 Functional Immune Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation: A Comparison of Pre- and post-transplantation Cytokine Responses in Stimulated whole-blood Lars Klingen Gjærde, Sisse Rye Ostrowski, Niels Smedegaard Andersen, Lone Smidstrup Friis, Brian Thomas Kornblit, Søren Lykke Petersen, Ida Schjødt, Henrik Sengeløv P480 Measurable Residual Disease (MRD) Testing for Acute Leukemia in EBMT Transplant Centers: A Survey on Behalf of The ALWP of the EBMT Arnon Nagler1,2, Myriam Labopin3, Emmanuelle Polge3, Jordi Esteve4, Ali Bazarbachi5, Eolia Brissot6, Gesine Bug7, Fabio Ciceri8, Sebastian Giebel9, Maria Gilleece10, Norbert-Claude Gorin11, Francesco Lanza12, Zina Peric13, Annalisa Ruggeri14, Jaime Sanz15, Bipin Savani16, Christoph Schmid17, Roni Shouval1,18, Alexandros Spyridonidis19, Jurjen Versluis20, Frederic Baron21, Mohamad Mohty22 P481 TBF Regimen Induces Full Donor Chimerism after Allografts in Myelofibrosis Patrizia Chiusolo1, Sabrina Giammarco1, Teresa Lamparelli2, Lucia Casarino3, Alida Dominietto2, Anna Maria Raiola2, Carmen Di Grazia2, Francesca Gualandi2, Monica Rossi1, Federica Sorà1, Simona Sica1, Andrea Bacigalupo1, Emanuele Angelucci2 P482 Real World Utility of Treating Minimal Residual Disease after Allogeneic Hematopoietic Cell Transplantation for Acute Myeloid Leukemia Elizabeth F. Krakow1,2, Kelsey K. Baker1, Ted A. Gooley1, Julia M. Nathe2, Tess M. Perez2, Mary E. Flowers1,2, Marco Mielcarek1,2, Brenda M. Sandmaier1,2 P483 Comparison of Immune Recovery in Cord Blood and T and B Depleted Haploidentical Grafts Recipients Chiara Mainardi, Giulia Reggiani, Manuela Tumino, Antonio Marzollo, Elisabetta Calore, Marta Pillon, Maria Vittoria Gazzola, Roberta Destro, Daniela Bovo, Piero Marson, Tiziana Tison, Anna Colpo, Alessandra Biffi P484 The BCR-ABL P210 Chimeric Transcript in Vitro Transfer into Bone Marrow Mesenchymal Stromal Cells Via Exosomes Ildar Barkhatov1, Anna Parfenenkova2, Anton Kremlev1, Olga Epifanovskaya1, Boris Afanasyev1 P485 Prognostic Significance of donor-specific Isoagglutinin re-appearance in abo-mismatched Stem Cell Transplant Recipients Maryam Pourabdollah, Christine Cserti, Dennis Dong Hwan Kim, Eshetu Atenafu, Ivan Pasic, Zeyad Al-Shaibani, Aijun Law, Wilson Lam, Armin Gerbitz, Jeffery Lipton, Auro Viswabandya, Rajat Kumar, Jonas Mattson, Fotios Michelis, Nayana Sondi, Jacob Pendergrast P486 Immune-reconstitution of Lymphocyte Subpopulations with Respect to Msc-treatment for Steroid Refractory GVHD following HSCT Emilia Salzmann-Manrique1, Zyrafete Kuci1, Selim Kuci1, Lisa-Marie Pfeffermann1, Halvard Bonig2, Martin Hutter1, Jan Soerensen1, Thomas Klingebiel1, Claudia Cappel1, Evelyn Ullrich1, Melanie Bremm1, Sabine Huenecke1, Peter Bader1 P487 Donor Factors Influence Outcomes of Patients Receiving Donor Lymphocyte Infusion for Mixed Chimerism after Reduced Intensity Conditioning Allogeneic Stem Cell Transplantation Jose Ros Soto1, John A Snowden2, Richard Szydlo3, Emma Nicholson4, Alejandro Madrigal1, Sandra Easdale4, Mark Ethell4, Mike Potter4, Chloe Anthias1,4 P488 Determine Patients at Risk of Relapse and Death in Acute Leukemia and Myelodysplasic Syndrome using Chimerism on Bone Marrow Samples at Day 28 after HSCT Julien Vaidie, Matthieu Filloux, V Pascal, B Trouche-Estival, L Boccelari, Jean-Luc Deprade, Stéphane Girault, David Rizzo, Natahlie Gachard, Pascal Turlure P489 Concurrent- Synergistic Assessment of Two Techniques in Monitoring Minimal Residual Disease for Ph(-) Acute Lymphoblastic Leukemia Post Allogeneic Transplantation Leads to Favorable Clinical Outcomes Apostolia Papalexandri, Vassiliki Douka, Christos Demosthenous, Natassa Konstantinou, Ioannis Eftychidis, Maria Papathanasiou, Anastasia Marvaki, Fotini Kika, Rita Avramidou, Angeliki Paleta, Georgia Konstantinidou, Despina Mallouri, Ioannis Batsis, Varvara Tachinopoulou, Tasoula Touloumenidou, Aliki Tsompanakou, Ioanna Sakellari, Achilles Anagnostopoulos P490 Donor Chimerism Evaluation of MRD-suspected Cells Isolated by flow Cell Sorting is an Accessible Tool for MRD Verification in Patients After Allogeneic HSCT Alexandra Semchenkova, Vladimir Zhogov, Varvara Brilliantova, Olga Illarionova, Larisa Shelikhova, Michael Maschan, Alexander Popov P491 Donor Lymphocyte Infusions Augment Graft versus Malignancy Effect following alemtuzumab-based Reduced Intensity Allografts: Reflections on a Single Centre Study Rebecca Lloyd, Graham McIlroy, Nervana Abou-Zeid, Claire Horgan, Richard Lovell, Bhuvan Kishore, Julie Suhr, Charmaine Campbell, Kathleen Holder, Beena Salhan, Shankara Paneesha, Emmanouil Nikolousis, Alexandros Kanellopoulos P492 Myeloid-derived Suppressor Cells Recover Quickly Following Autologous Hematopoietic Stem Cell Transplantation in Multiple Myeloma Patients Vera Sergeevicheva, Egor Batorov, Tatiana Aristova, Svetlana Sizikova, Galina Ushakova, Andrey Gilevich, Ekaterina Shevela, Alexandr Ostanin, Elena Chernykh P493 Uninterrupted Mobilization and Transplantation Procedure with Non-cryopreserved Yield is Feasible without Increasement of Complication Risk in Multiple Myeloma Patients Zübeyde Nur Özkurt, Ayşe Asena Dikyar, Zeynep Arzu Yeğin, Lale Aydın Kaynar, Özlem Karacaoglu, Emin Ateş P494 Conditioning with Bortezomib-MEL200 in Comparison to MEL200 Improves Survival Among Myeloma Patients IN≤PR Prior to Auto-HCT: A Study from the CMWP of the EBMT Meral Beksac1, Diderik-Jan Eikema2, Zubeyde Nur Ozkurt3, Linda Koster4, Didier Blaise5, Patrice Chevallier6, Lionel Karlin7, Cyrille Hulin8, Kim Orchard9, Xavier Poiré10, Xavier Leleu11, Mohamad Mohty12, Rose-Marie Hamladji13, Malgorzata Wach14, Marco Casini15, Karim Belhadj16, Gunhan Gurman1, Tessa Kerre17, Alexandros Spyridonidis18, Emmanuelle Nicolas-Virelizier19, José Mª Moraleda20, Liesbeth C. de Wreede21, Patrick Hayden22, Stefan Schönland23, Ibrahim Yakoub-Agha24 P495 P496 In Vitro Stimulation with CD40l/il-21 Can Retrieve B-cell Dysfunction in Multiple Myeloma Patients Suffering from Secondary Immunodeficiency Clarissa Heck1, Sophie Steiner1, Marco Frentsch2, Friedrich Wittenbecher1, Carmen Scheibenbogen1, Axel Nogai1, Philipp le Coutre1, Lars Bullinger1, Igor Wolfgang Blau1, Il-Kang Na1,2,3 P497 Allogeneic Stem Cell Transplantation for Multiple Myeloma; Excellent Outcomes for Early Transplantation Mariam Amer, Deborah S. Richardson, Christopher Dalley, Kate S. Hill, Sara Main, Helen Snow, Amanda Blackwell, Amy Creighton, Joan Newman, Nikki Mckeag, Linda Jarvis, Sarah Holtby, Kim H. Orchard P498 Results of Autologous Stem Cell Transplantation in Patients with Monoclonal Immunoglobulin Deposition Disease Natalia Tovar1, Maria Teresa Cibeira1, Manel Sole1, Laura Rosinol1, Carlos Fernandez de Larrea1, Lourdes Escoda2, Carme Talarn2, Paola Castillo1, Luis Quintana1, Juan Ignacio Arostegui1, Jose Tomas Ortiz1, Montserrat Rovira1, Joan Blade1 P499 P500 Aberrant Phenotype Plasma Cell Multiparametric Flow Cytometry (MFC) Detection in Autograft Products of Newly Diagnosed Multiple Myeloma (NDMM) Riccardo Boncompagni, Michela Staderini, Chiara Nozzoli, Elisabetta Antonioli, Roberto Caporale, Benedetta Peruzzi, Blerina Jance, Stefano Guidi, Ilaria Cutini, Antonella Gozzini, Serena Mariotti, Agata Suellen Guarrera, Giulia Raugei, Alberto Bosi, Francesco Annunziato, Riccardo Saccardi P501 Retrospective Multi-center Study of Adolescent and Young Adult (AYA) Multiple Myeloma in Kansai Myeloma Forum Registry Aya Nakaya1,2, Takae Kohara2,3, Hirohiko Shibayama2,3, Yoshiyuki Onda2,4, Junya Kanda2,4, Hitomi Kaneko2,5, Kazunori Imada2,5, Toru Kida2,6, Satoru Kosugi2,6, Jun Ishikawa2,7, Ryosuke Yamamura2,8, Yutaka Shimazu2,9, Hirokazu Tanaka2,10, Shin-Ichi Fuchida2,11, Yuji Shimura2,12, Miki Kiyota2,13, Katsuya Wada2,13, Tomoki Ito1,2, Nobuhiko Uoshima2,14, Hideo Yagi2,15, Satoshi Yoshihara2,16, Kensuke Ohta2,17, Chihiro Shimazaki2,11, Masayuki Hino2,18, Akifumi Takaori-Kondo2,4, Junya Kuroda2,12, Itaru Matsumura2,10, Yuzuru Kanakura2,3, Shosaku Nomura1,2 P502 Autologous Stem Cell Trasplantation Candidacy in Patients with Newly Diagnosed Systemic Light-chain Amyloidosis Joan Bladé, Carlos Fernández de Larrea, Natalia Tovar, Laura Rosiñol, Raquel Jiménez, Jose T. Ortiz-Pérez, Luis Quintana, Manel Solé, Paola Castillo, Juan Ignacio Aróstegui, Ana Triguero, Esther Bladé, Carlos Castillo, María Suárez-Lledó, Gonzalo Gutiérrez-García, Montserrat Rovira, M. Teresa Cibeira P503 Novel Protocol for Autologous HSCT in Multiple Myeloma Achieves “Zero” Central Line associated Blood Stream Infections (CLABSI) Emilian Snarski, Agnieszka Tomaszewska, Martyna Maciejewska, Michał Górka, Anna Brodziak, Sara Zawadzka-Leska, Anna Waszczuk-Gajda, Jarosław Biliński, Marcin Jasiński, Karol Lis, Kamila Skwierawska, Hubert Heleniak, Mateusz Ziarkiewicz, Dorota Zduńczyk, Wojciech Sachs, Elżbieta Urbanowska, Magdalena Feliksbrot - Bratosiewicz, Małgorzata Król, Maria Król, Wiesław Wiktor-Jędrzejczak, Grzegorz Basak P504 Outcomes of Non-cryopreserved Versus Cryopreserved Peripheral Blood Stem Cells for Autologous Stem Cell Transplantation in Multiple Myeloma Pokpong Piriyakhuntorn, Adisak Tantiworawit, Thanawat Rattanathammethee, Sasinee Hantrakool, Chatree Chai-Adisaksopha, Ekarat Rattarittamrong, Lalita Norasetthada P505 Favorable Long-term Outcomes with Autologous Stem Cell Transplantation for High Risk Patients with Multiple Myeloma Who are Positive at FDG-PET/CT Hee Jeong Cho1, Dong Won Baek1, Ju Hyung Kim1, Sung Hoon Jung2, Sang Kyun Sohn1, Joon Ho Moon1 P506 Long Term Survival of Multiple Myeloma Patients after Autologous Stem Cell Transplantation (ASCT) in Relation to Availability of Novel Drugs Ozren Jaksic, Zeljko Prka, Mario Pirsic, Zdravko Mitrovic, Ena Soric, David Cicic, Tamara Vasilj, Zeljko Jonjic, Marko Lucijanic, Ivana Maricic, Gorana Dzepina, Rajko Kusec, Vlatko Pejsa P507 Multiple Myeloma (MM) in First Relapse Patients. Role of the Second Autologous stem-cell Trasplant (ASCT) in Real Life. Experience of Two Spanish Centers N Amer1, MT Villalobos2, R Del Campo1, JB Borràs1, A Porcel2, JM Guerra1, A Jaramillo2, A Cladera1, M Mascaró1, J Perales-Amengual1, M Canet2, P Vélez2, J Perales2, A Muntañola2, JA Soler3, M López2, M Díaz2, F Vall-llovera2, JM Martí2, J Bargay1 P508 Allogeneic Hematopoietic Stem Cell Transplant in Multiple Myeloma: Single Center Experience Analys Ruiz, Isabel Iturrate, Isabel Vicuña, Yisele Paz, Ángela Figuera, Adrián Alegre, Beatriz Aguado P509 Allogeneic Hematopoietic Stem Cell Transplant in Multiple Myeloma: Single Center Experience Analys Ruiz, Isabel Iturrate, Isabel Vicuña, Yisele Paz, Ángela Figuera, Adrián Alegre, Beatriz Aguado P510 Use of Netupitrant/palonosetron in Multiple Myeloma Patients Receiving High-dose Melphalan and Autologous Stem Cell Transplantation: A Single Centre Experience Barbara Loteta, Virginia Naso, Anna Ferreri, Tiziana Moscato, Giuseppe Console, Giuseppe Irrera, Fabio Provenzano, Giuseppa Cusumano, Letteria Russo, Nicola Meliambro, Valentina Romeo, Domenico Porcino, Salvatore Gallo, Tiziana Gangemi, Antonio Maria Rossetti, Massimo Martino P511 Safety and Effectiveness of Autologous Stem Cell Transplantation in Patients with Multiple Myeloma in First Line Pilar Velarde Lopez de Ayala, Rocío Zapata Bautista P512 Plasmapheresis Assisted the Treatment of 1 Case of Hyperglobulinemia after Cart Therapy XIUYAN TAO, WENWEN MA, Limei GAO, Jiajia Yue, Yuehui Lin P513 Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) in Patients with Therapy-related Myeloid Neoplasm: A Study from The Chronic Malignancies Working Party of the EBMT Marie Robin1, Junfeng Wang2, Linda Koster3, Dietrich Beelen4, Martin Bornhaeuser5, Nicolaus Kroeger6, Uwe Platzbecker7, Jurgen Finke8, Arnold Ganser9, Didier Blaise10, Fabio Ciceri11, Johan Maertens12, Hélène Labussière13, Patrice Chevallier14, Jakob Passweg15, Jan J Cornelissen16, Carmen Botella17, Amandine Charbonnier18, Francesca Bonifazi19, Katya Mauff2, Liesbeth de Wreede20, Patrick Hayden21, Christoph Scheid22, Ibrahim Yakoub-Agha23 P514 Impact of Mutation Profile in Chronic Myelomonocytic Leukemia undergoing Allogeneic Hematopoietic Cell Transplantation Nico Gagelmann1, Anita Badbaran1, Rashit Bogdanov2, Friedrich Stölzel3, Christina Rautenberg4, Olivier Nibourel5, Heiko Becker6, Aleksandar Radujkovic7, Peter Dreger7, Maximilian Christopeit1, Jürgen Finke6, Uwe Platzbecker8, Guido Kobbe9, Michael Koldehoff2, Markus Ditschkowski2, Dietrich Beelen2, Marie Robin10, Nicolaus Kröger1 P515 Outcome and Mutational Profile in MDS Patients undergoing Allogeneic Hematopoietic Stem Cell Transplantation Nikolai Tcvetkov, Elena Morozova, Ildar Barkhatov, Ivan Moiseev, Maria Barabanshikova, Artem Tishkov, Dmitrij Bug, Ekaterina Izmailova, Sergey Bondarenko, Boris Afanasyev P516 Nivolumab Increases Antigen Specific Immune Responses Against Leukemic Progenitor and Stem Cells (LSC/LPC) Jochen Greiner1,2, Vanessa Schneider2, Hubert Schrezenmeier3, Markus Wiesneth3, Lars Bullinger2,4, Hartmut Döhner2, Susanne Hofmann5, Marlies Götz2 P517 Eltrombopag for the Treatment of Poor Graft Function following Allogeneic Stem Cell Transplants : A Multicenter Survey Update Sabrina Giammarco1, Simona Sica2, Patrizia Chiusolo3, Luca Laurenti3, Federica Sorà3, Massimo Martino4, Alessandro Busca5, Antonio Risitano6, Carlos Valejo7, Andrea bacigalupo8 P518 Donor NK Cells Infusion as a Strategy of Immunotherapy to Prevent HHV6 Reactivation in Pediatric Patients after CD45RA-depleted Transplantation Mercedes Gasior Kabat1, Luisa Sisinni1, Raquel De Paz1, David Bueno1, Yasmina Mozo1, Antonio Marcos1, Ana Belen Romero1, Aida Constanzo1, Victor Jimenez Yuste1, Antonio Pérez-Martínez1,2 P519 Development of Cell Vaccine Based on Autologous Dendritic Cells Loaded with Lipid Nanoparticles Containing CMV PP65 Messenger RNA Ruslan Nikolaev, Yana Bayzyanova, Natalya Khripkova, Mariya Efimenko, Timofei Zatsepin, Elena Osipova, Michael Maschan P520 Smac Mimetics (SM) and Natural Killer (NK) Cells - A Promising Combination to Overcome Cell Death Resistance of Rhabdomyosarcoma (RMS) Cells Vinzenz Särchen1, Lisa Marie Reindl2,3, Jonas Heck2,3, Meike Vogler1, Thomas Bukur4, Valesca Bukur4, Thomas Klingebiel2, Simone Fulda1,5,6, Evelyn Ullrich2,3,6 P521 Role of Exosomes as Promotors or Biomarkers To Study Activation of Leukemia-derived Dendritic Cells (DCLEU)-mediated Antileukemic Activation of Adaptive and Innate Immune-reactive Cells against AML-blasts Lin Li1, Veronika mussack2, Elena Pepeldjiyska1, Anne Hartz1, Andreas Rank3, Christoph Schmid3, Erdem Özkaya1, Selda Ugur1, Michael Pfaffl2, Helga Schmetzer1 P522 Blinatumomab for the Treatment of Relapsed/refractory B-acute Lymphoblastic Leukemia: Report from a Single Center Sabrina Giammarco1, Patrizia Chiusolo2, Elisabetta Metafuni1, Federica Sorà2, Luca Laurenti2, Idanna Innocenti1, Francesco Autore1, Andrea Bacigalupo2, Simona Sica2 P523 IFNY Secretion of Adaptive and Innate Immune Cells as a Parameter to Display Leukaemia Derived Dendritic Cell (DCLeu) Mediated Immune Responses in AML Lara Kristina Klauer1, Olga Schutti1, Selda Ugur1, Fatemeh Donareh-Gard1, Nicole Rogers1, Melanie Weinmann1, Doris Krämer2, Andreas Rank3, Christoph Schmid3, Britta Eiz-Vesper4, Helga Maria Schmetzer1 P524 Treatment of Severe Hematopoietic Stem Cell transplant-associated Thrombotic Microangiopathy (HCT-TMA) with the masp-2 Inhibitor Narsoplimab (OMS721) Irene Romera, María Martínez Múñoz, Carlos de Miguel, Isabel Salcedo, Marta Manso, Ana Alarcón, Daniel Naya, Begoña Pérez de Camino, Guiomar Bautista, Rafael Cabrera, Rafael F. Duarte P525 Factors Influencing the Presence of Bone Marrow Mesenchymal Stem Cells after Allogeneic Stem Cell Transplantation Judith Schaffrath1, Ole Vollstädt1, Jana Lützkendorf1, Christiane Katzerke1, Josephine Schneider2, Lisa Maria Siol1, Mascha Binder1, Lutz P. Müller1 P526 Analysis of the Genetic Stability of Donors` Bone Marrow Stroma Mesenchymal Cells during Cultivation Konstantin Vetoshkin, Maria Loginova, Svetlana Kutyavina, Maria Sarpova, Maria Butolina, Natalya Minaeva P527 The Polish Experience of Wharton´s Jelly-derived Mesenchymal Stem Cell Treatment of Paediatric Patients Maciej Rojek, Michał Piątek, Izabela Zdolińska-Malinowska, Dariusz Boruczkowski P528 The Polish Experience of Wharton´s jelly-derived Mesenchymal Stem Cell Treatment of Adult Patients Maciej Rojek, Izabela Zdolińska-Malinowska, Michał Piątek, Dariusz Boruczkowski P529 Bacterial and Metabolic Profiling of the Saliva Identifies Unique Patterns of Microbiota Injury in Hematopoietic Stem Cell Transplantation Recipient with Severe Oral Mucositis Roni Shouval1,2, Adi Eshel3, Amir Kuperman3,4, Ivetta Danylesko1, Bar Dubovski3, Joshua A Fein1, Shalev Fried1, Mika Geva1, Elizaveta Kouniavsky1, Efrat Muller5, Elhanan Borenstein5, Yoram Louzoun3, Omry Koren3, Arnon Nagler1 P530 Diagnosis and Management of Secondary HLH/MAS following HSCT and CAR-t Cell Therapy in Adults; An EBMT-wide Survey on Behalf of the ADWP and TCWP Robert David Sandler1, Rachel Scarlett Tattersall1, Helene Schoemans2,3, Raffaella Greco4, Manuela Badoglio5, Myriam Labopin5, Tobias Alexander6, Kirill Kirgizov7, Montserrat Rovira8, Muhammad Saif9, Riccardo Saccardi10, Julio Delgado8, Zinaida Peric11,12, Christian Koenecke13, Olaf Penack6, Grzegorz Basak14, John Andrew Snowden1 P531 Impact of Abo Incompatibility on Complications of Allogeneic Hematopoietic Cell Transplantation- Retrospective, International, Multicenter Analysis by the Transplant Complications Working Party EBMT Michal Gorka1, Christophe Peczynski2, Emmanuelle Polge2, Karol Lis1, Riitta Niittyvuopio3, Hélène Labussière Wallet4, Zinaida Peric5, Helene Schoemans6, Olaf Penack7, Nina Worel8, Christian Koenecke9, Grzegorz Wladyslaw Basak1 P532 Hypoalbuminemia Prior AlloHCT is a Relevant Negative Predictor for Survival Maria Queralt Salas1,2, Eshetu G Atenafu2, Arjun D. Law1,2, Wilson Lam1,2, Zeyad Al-Shaibani1,2, Ivan Pasic1,2, Dennis (Dong Hwan) Kim1,2, Fotios V Michelis1,2, Armin Gerbitz1,2, Auro Viswabandya1,2, Jeffrey Howard Lipton1,2, Jonas Mattsson1,2, Rajat Kumar1,2 P533 Incidence and Clinical Impact of Atrial Fibrillation Diagnosed during Hospital Stay for Allogeneic Stem Cell Transplantation Catherina Lueck, Gernot Beutel, Victoria Panagiota, Elke Dammann, Dominik Markel, Maleen Beck, Souheila Tayeb, Adrian Schwarzer, Daniel Kharazipour, Michael Stadler, Arnold Ganser, Matthias Eder P534 Transplantation-associated Microangiopathy (TAM) in Recipients of Unmanipulated HLA-haploidentical Hematopoietic Stem Cell Transplants using Ptcy for GVHD Prophylaxis: Incidence and Outcome Alessia Fraccaroli, Dusan Prevalsek, Veit Bücklein, Heidrun Drolle, Ulf Schoenermarck, Michael von Bergwelt, Johanna Tischer P535 IGF-1 and IGFBP-3 Gene Polymorphisms Predict Circulating IGF Levels and Systemic Inflammation in Allogeneic Hematopoietic Stem Cell Transplantation Maria Schou Ebbesen, Christian Enevold, Anders Juul, Carsten Heilmann, Henrik Sengeløv, Klaus Müller P536 Low Risk of Early Toxicity and Unplanned 100-day Readmissions after Matched and Mismatched Related and Unrelated Donor Allogeneic Hematopoietic Stem Cell Transplantation with post-transplantation Cyclophosphamide Irene García-Cadenas, Albert Esquirol, Rahinatu Awol, Silvana Saavedra, Silvana Novelli, Ana Garrido, Jordi López, Carol Moreno, Miquel Granell, Javier Briones, Salut Brunet, Jordi Sierra, Rodrigo Martino P537 Keratinocyte Growth Factor Decreases Hospital Readmission and Regimen-related Toxicities after Autologous Stem Cell Transplantation for Lymphoma Najla El Jurdi, Christina Fair, John Rogosheske, Ryan Shanley, Daniel Weisdorf, Shernan Holtan, Mukta Arora, Veronika Bachanova, Claudio Brunstein P538 Systemic Corticosteroid Therapy is Unlikely to be the Primary Cause of Hyperglycemia following Treatment of Acute Graft-versus-host Disease Anna Guo1, LaQuisa Hill2, Gabriela Rondon3, Richard E. Champlin3, Amin M. Alousi3, Rima M. Saliba3 P539 Cost-effectiveness Analysis of Defibrotide for the Treatment of Severe Veno-occlusive Disease/sinusoidal Obstruction Syndrome in Spain David Carcedo Rodriguez1, Teresa Artola Urain2, Anabelle Chinea Rodriguez3, Estefanía García Torres4, Marta González Vicent5, Gonzalo Gutiérrez-García6, Alexandra Regueiro García7, Marcos Calvo Hidalgo8, Alba Villacampa1 P540 Neurologic Complications IIN 169 Consecutive Allogeneic Stem Cell Transplants: Etiology, Clinical Syndromes and Outcome Ilaria Scortechini, Elena Inglese, Monica Poiani, Francesco Saraceni, Giorgia Mancini, Giuseppina Urbano, Irene Federici, Marianna Mariani, Giorgia Micucci, Attilio Olivieri, Gabriele Polonara P541 Venetoclax, Hypomethylating Agents and Dli for Salvage Treatment of Myeloid Malignancies Relapsing after Allogeneic Hematopoietic Stem Cell Transplantation Esther Schuler1, Eva-Maria Wagner-Drouet2, Salem Ajib3, Gesine Bug3, Martina Crysandt4, Sabine Dressler5, Andreas Hausmann6, Daniela Heidenreich7, Klaus Hirschbühl8, Matthias Hoepting9, Edgar Jost4, Jennifer Kaivers1, Stefan Klein7, Lambros Kordelas10, Oliver Kriege2, Lutz Müller11, Christina Rautenberg1, Judith Schaffrath11, Christoph Schmid8, Daniel Wolff9, Rainer Haas1, Martin Bornhäuser12, Thomas Schroeder1, Guido Kobbe1 P542 Evaluation of TGF-beta Level After Supplementation with Whey Protein Concentrate for Oral Mucositis Prophylaxis Ana Carolina Amaral de Sao Jose Perrone1,2, Clarissa Ferreira Cunha2, Ana Paula da Silva Pinheiro1, Ítalo Tuler Perrone1, Leonardo Barbosa de Almeida1,2, Kelli Borges dos Santos1, Rodrigo Stephani1, Henrique Couto Teixeira1, Paula Alexandra da Graça Morais1, Antonio Fernandes de Carvalho3, Abrahao Elias Hallack Neto1,2 P543 Treosulfan-induced Myalgia in Pediatric Hematopoietic Stem Cell Transplantation Eileen van der Stoep, Dagmar Berghuis, Robbert Bredius, Emmeline Buddingh, Henk-Jan Guchelaar, Alex Mohseny, Irene Klaassen, Frans Smiers, Arjan Lankester, Juliette Zwaveling P544 Validation of Early Increase of SC5B-9 as a Predictive Marker for Later Transplantation Associated Thrombotic Microangiopathy Orsolya Horváth1, Blanka Mező2, Krisztián Kállay1, János Sinkó1, Dorottya Csuka2, Csaba Kassa1, Judit Nyirő1, Gabriella Kertész1, Lídia Hau1, Nóra Veszeli2, György Sinkovits2, Zoltán Prohászka2, Gergely Kriván1 P545 Early Transjugular Intrahepatic Portosystemic Shunt (TIPS) Insertion Improves Outcome of Very Severe Hepatic Veno-occlusive Disease/sinusoidal Obstruction Syndrome (VOD/SOS) after Unmanipulated Haploidentical HSCT with Post-transplantation Cyclophosphamide Ignacio Gómez-Centurión1, Cristina Muñoz1,2, Arturo Alvárez Luque1,2, Miguel Echenagusia Boyra1,2, Diego Rincón1,2, Nieves Dorado1,2, Rebeca Bailén1,2, Gillen Oarbeascoa1,2, Javier Anguita1,2, José Luis Díez-Martín1,2, Mi Kwon1,2 P546 Neurological Complicantions in Adult Allogeneic Hematopoietic Stem Cell Transplant Patients: Results from a Retrospective Multicenter Study Michele Wieczorek1, Beatrice De Marco1, Federico Mosna2, Carlo Borghero3, Maria Vittoria Dubbini4, Anna Candoni4, Michele Malagola5, Marco Ruggeri3, Angelo Andreini1, Mauro Krampera1, Fabio Benedetti1, Cristina Tecchio1 P547 Allogeneic Stem Cell Transplantation Recipients Admitted to the Intensive Care Unit - Reappraisal of Prognosis and Prognostic Factors - A Single Center Study Natacha Mauz, Pierre Crétallaz, Anne-Sophie Truche, Nicholas Sédillot, Martin Carré, Claude-Eric Bulabois, Carole Schwebel, Nicolas Terzi, Jean-Yves Cahn, Anne Thiebaut-Bertrand P548 Enteral Versus Parenteral Nutrition in Adult Hematopoietic Cell Transplantation Recipients Suffering from Gastrointestinal Mucositis Lenneke van Groningen1, Doris Kalter1, Wim Tissing2, Walter van der velden1, Nicole Blijlevens1 P549 Delayed Engraftment and Prolonged Hospital Stay Following Omission of Folinic Acid after Methotrexate for GVHD Prophylaxis in Allogeneic Transplant Recipients Duncan Purtill, Ghassan Zammar, Hutchison Andrew, Julian Cooney, Paul Cannell, Matthew Wright P550 The Usefulness of Liver Stiffness Measurement before Hematopoietic Stem Cell Transplantation to Predict Sinusoidal Obstruction Syndrome Vera Radici1, Chiara Rosignoli1, Rossella Stella1, Maria Vittoria Dubbini1, Alessandra Sperotto1, Michela Cerno1, Antonella Geromin1, Marta Lisa Battista1, Giorgio Soardo2, Laura Scatà2, Renato Fanin1, Francesca Patriarca1 P551 Endothelial Cell Complications after Allogeneic Stem Cell Transplantation, A Single Centre Analysis on 99 Consecutive Patients undergoing allo-sct Giorgia Mancini1, Matteo Candelora2, Giuseppina Urbano2, Francesco Saraceni1, Monica Poiani1, Marianna Mariani1, Irene Federici1, Giuseppe Tarantino1, Ilaria Scortechini1, Attilio Olivieri1 P552 Influence of Abo-incompatibility on the Outcome of Stem Cell Transplantation - A Retrospective Study on Children and Young Adults Volker Witt, Herbert Pichler P553 P554 Veno-occlusive Disease: Online, Interprofessional, Case-based Education Significantly Improves Knowledge and Skills of the Entire Care Team Lauren Willis1, Mindy Tanzola1, Tristin Abair1, Pan Chen1, Cathryn Jennissen2, Alison Bemis2, Angela R. Smith2 P555 Hyperhemolysis Syndrome is a Novel Cause of Severe Hemolytic Anemia after Allogeneic Transplantation with Very Poor Response to Treatment and Outcome José Luis Bueno1,2, Azucena Losa1, Clara González Santillana1, Begoña Perez de Camino1, Guiomar Bautista1,2, Irene Romera1, Ana Alarcón1, Daniel Naya1, Cristina Teresa Fernández-Maqueda1, Carlos de Miguel1,2, María Esther Martinez-Muñoz1,2, Almudena De Laiglesia1,2, Laura Vicente1, José Antonio García-Marco1,2, Rafael Forés1,2, José Rafael Cabrera1,2, Rafael F Duarte1,2 P556 Easix as a Predictive Biomarker of Complications and Outcome in Allogeneic Hematopoietic Cell Transplantation Carlos de Miguel, Clara Isabel González, José Ramón Álamo, Lucia Núñez, Ángela Benéitez, Sara Garrido, Ana Bocanegra, Marta Liébana, José Miguel Mateos, María Esther Martínez-Muñoz, Rafael F. Duarte P557 Survival with Normal Pulmonary Function is Possible Despite Significant and Prolonged Respiratory Support, Including Prolonged High Frequency Oscillatory Ventilation (HFOV) in Children Ramya Nataraj, Praveen Kurup, Alok Ekka, Gayathri Subramanian, Omendra Narayan, Denise Bonney, Helen Campbell, Hemalatha Doss, Robert Wynn P558 Use of Intravesical Hyaluronic Acid to Treat Hemorrhagic Cystitis after Hematopoietic Cell Transplantation María Esther Martínez-Muñoz1,2, Guiomar Bautista1,2, Belén Navarro1,2, Cristina Fernández-Maqueda1,2, Carlos de Miguel1,2, Miguel Piris1, Martín Cabero1, Carmen Regidor1,2, Almudena de Laiglesia1,2, Jose Luis Bueno1,2, Jose Rafael Cabrera1,2, Joaquín Alberto Carballido1, María Rodríguez-Monsalve1, Patricia Ramírez1, Francisca Portero1, Rafael Franciso Duarte1,2 P559 Current Practice in Nutrition after Allogeneic Hematopoietic Stem Cell Transplantation in Austria, Germany and Switzerland Rosa Toenges1, Matthias Edinger2, Gesine Bug1, Anita Lawitschka3,4, Hildegard Greinix5, Jörg Halter6, Jann Arends7, Francis Ayuk8, Stefan Klein9, Jan-Moritz Middeke10, Eva Wagner-Drouet11, Inken Hilgendorf12, Annic Baumgartner13, Daniel Wolff2 P560 Incidence and Severity of Cytokine Release Syndrome Following Haploidentical Peripheral Blood Stem Cell Infusion Frank Cirrone, Jamie Pavlonnis, Kelli Cole, Maher Abdul-Hay, Doyun Park, A Samer Al-Homsi P561 Engraftment Syndrome Following Autologous Hematopoietic Stem Cell Transplantation: Retrospective Study from a Single Center Dorra Belloumi, Rimel Kanoun, Rim Cherni, Rym El Fatmi, Lamia Torjemane, Nour Abdeljelil, Amel Lakhal, Saloua Ladeb, Tarek Ben Othman P562 Wernicke’s Encephalopathy in a Child with B Lymphoblastic Lymphoma after HAPLO-HSCT Natalya Natrusova, Evgeny Burtsev, Bulat Kurmanov, Inna Schederkina, Gleb Bronin P563 Eculizumab for the Treatment of Severe Transplant-associated Thrombotic Microangiopathy: Multicenter Experience Dana Yehudai-Ofir1, Israel Henig1, Avraham Frisch1, Avichai Shimoni2, Batia Avni3, Sigal Grisariu3, Ron Ram4, Moshe Yeshurun5, Tsila Zuckerman1,6 P564 Impact of Post-transplant Cyclophosphamide (CYPT) as Graft-versus-host Disease (GVHD) Prophylaxis in Terms of Sinusoidal Obstruction Syndrome (SOS) Javier Cornago Navascués1, Ana Lerma Verdejo2, Clara Cuéllar Pérez-Ávila3, Begoña Pérez de Camino Gaisse1, Pilar Llamas Sillero1, José Luis López Lorenzo1 P565 Ischemic Stroke in Children and Young Adults with Malignant Hematological and Oncological Diseases in Allogeneic Hematopoietic Stem Cell Transplantation Alexey Polushin, Oleg Goloshchapov, Tatiana Khutornaya, Olesya Paina, Tatiana Bykova, Asmik Gevorgian, Zhamal Rahmanova, Anastasia Frolova, Maria Vladovskaya, Ivan Moiseev, Ludmila Zubarovskaya, Boris Afanasyev P566 Melphalan Dose Adjustment and Cryotherapy Reduce Oral Mucositis after Autologous Hematopoietic Stem Cell Transplantation Marcin Jasiński, Martyna Maciejewska, Michał Górka, Anna Brodziak, Kamila Skwierawska, Wiesław Wiktor-Jędrzejczak, Agnieszka Tomaszewska, Grzegorz Basak, Emilian Snarski P567 Clinical Features and Risk Factors of Engraftment Syndrome in Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation Berta Michael Fernández, Valentín García Gutiérrez, Irene García García, Fernando Martín Moro, Adolfo Sáez Marín, Alejandro Luna de Abia, Claudia Núñez-Torrón Stock, Pilar Herrera Puente, Anabelle Chinea Rodríguez, Gemma Moreno Jiménez, Javier López Jiménez P568 Real-life Experience of Two Italian Hematolgy Centres on Efficacy and Safety of Oral Nepa (Netupitant/palonosetron) in Patients with Multiple Myeloma Undergoing Hematopoietice Stem Cell Transplantation Clara De Risi1, Anna Mele1, Domenico Pastore2, Lorenzo Tonialini1, Antonino Greco1, Giuseppina Greco1, Silvia Sibilla1, Rosa De Francesco1, Alessandro Spina2, Francesca Merchionne2, Stefania Citiso1, Eleonora Prete1, Mariarosaria Morciano1, Vincenzo Pavone1 P569 Early Treatment with Daratumumab for Refractory Post-Allogeneic Stem Cell Transplant Pure Red Cell Aplasia Rahinatu Awol, Irene Garcia-Cadenas, Albert Esquirrol Santfeliu, Silvana Saavedra Gerosa, Jordi Sierra Gil, Rodrigo Martino Bufarull P570 Prognostic Factors for Early Mortality of Hematological Patients Admitted to the Intensive Care Unit: Preliminary Results of A Prospective Multicenter Study Francisco Manuel Martín Domínguez1, Joao Lameirao Gaspar2, Marta Reinoso Segura1, Rocío Parody Porras3, Eva Domingo Domènech3, Gabriel Moreno-González3, Marta González Vincent4, Pedro Antonio González-Sierra5, Manuel Jurado Chacón5, Eusebio Martín Chacón6, María Dolores Madrigal Toscano6, Manuel Gracia Romero6, Christelle M Ferra Coll7, María José Jiménez7, María Pilar Marcos7, Ana Jiménez-Ubieto8, María Calbacho Robles8, Silvia Chacón Alves8, Nancy Rodríguez Torres1, José Francisco Falantes González1, José González-Campos1, Isabel Montero Cuadrado1, Juan Luis Reguera Ortega1, Eduardo Rodríguez-Arbolí1, José Antonio Pérez-Simón1, Yael Corcia Palomo2, Espigado Ildefonso1 P571 T-PA/Urokinase in Combination with TPE as a Substitutional Therapy for Treatment of TA-TMA Fei Zhou1,2,3, Xuefeng He3 P572 Hemophagocytic Syndrome after Ex-vivo Lymphodepleted Hematopoietic Transplantation Luisa Sisinni, Yasmina Mozo, David Bueno, Raquel De Paz, Eduardo Lopez-Granados, Antonio Perez-Martinez P573 Immunoadsorption in Hematopoietic Stem Cell Transplantation with Major ABO Incompatibility Martina Crysandt1, Eva Jennes2, Klaus Strathmann1, Uta Kunter1, Stefan Wilop3, Gerda Silling1, Tim H Brümmendorf1, Fabian Beier1, Edgar Jost1 P574 Immune-mediated Fever after T-cell Replete Haploidentical HSCT using Peripheral Blood Stem Cell Grafts and Post-transplantation Cyclophosphamide Prashant Mehta1, Rahul Arora1, Vikash Kumar1, Siddharth Sood1, Swati Pabbi2, Jagsahib Kaur1 P575 Bronchiolitis Obliterans Syndrome in the Changing Landscape of Allogeneic Hematopoietic Stem Cell Transplantation Egor Kulagin, Alisa Volkova, Ilya Nikolaev, Julia Rabik, Victoria Timchick, Anna Smirnova, Tatiana Bykova, Tatiana Rudakova, Elena Darskaya, Alexander Alyanskiy, Ivan Moiseev, Sergey Bondarenko, Vasiliy Trofimov, Boris Afanasyev P576 Current Status and Needs of Long-term Follow-up Clinics for Hematopoietic Cell Transplant Survivors: Results of a Nationwide Survey in Japan Saiko Kurosawa1,2, Ayako Mori1, Mayumi Tsukagoshi3, Yasushi Onishi4, Chikako Ohwada5, Takehiko Mori6, Hideki Goto7, Yuki Asano-Mori8, Yuichiro Nawa9, Masayuki Hino10, Tomoko Fukuchi11, Yasuo Mori12, Reiko Yamahana13, Yoshihiro Inamoto1, Takahiro Fukuda1 P577 Survivorship Care for Allogeneic Transplant Patients in The UK: Current Service Provision and Barriers to Implementation Fiona Dignan1, Angela Hamblin2, Amelia Chong3, Julia Perry4, Michelle Kenyon5, Paul Miller3, Maria Gilleece6, Hannah Hunter7, John Snowden8 P578 Whole Body Vibration Training during Allogeneic Hematopoietic Cell Transplantation - The Effects on Patients´ Physical Capacity, Fatigue, Body Compsition and Quality of Life Hartmut Bertz, Anja Wehrle, Sarah Kneis, Albert Gollhofer, Jürgen Finke, Antonia Pahl P579 Multi-morbidity in Adult Survivors of Stem Cell Transplantation (SCT) Lubna Ghani, Jeannie Todd, Jane Apperly, Nina Salooja P580 Gonadotoxicity after Treosulfan-based Myeloablative Conditioning Regimen for Allogeneic HSCT in Girls with Leukemia Irina Kostareva, Yuliya Skvortsova, Elena Iliina, Nataliya Radlevich, Lyudmila Papusha, Dmitriy Balashov, Anna Livshits, Andrey Abrosimov, Larisa Shelikhova, Darya Shasheleva, Kirill Voronin, Michael Maschan, Aleksey Maschan P581 Reduced-intensity Transplantation in Patients Older than 65 Years with High-risk or Advanced Hematological Malignancies in Last 10 Years - Single Centre Experience Michal Karas, Katerina Steinerova, Marcela Hrabetova, Daniel Lysak, Alexandra Jungova, Lekaa Mohammad, Jiri Sramek, Pavel Jindra P582 Fatherhood after a Myeloablative Treosulfan Based Allogeneic Stem Cell Transplantation: Analysis on 453 Patients Maria Teresa Lupo-Stanghellini1, Andrea Assanelli1, Fabio Giglio1, Carlo Messina1, Raffaella Greco1, Daniela T. Clerici1, Sara Mastaglio1, Francesca Pavesi1, Francesca Farina1, Stefania Girlanda1, Francesca Lorentino1, Simona Piemontese1, Sarah Marktel1, Francesca Lunghi1, Matteo G Carrabba1, Magda Marcatti1, Massimo Bernardi1, Consuelo Corti1, Jacopo Peccatori1, Fabio Ciceri1,2 P583 Older Age and Peripheral Blood as a Stem Cell Source are the Major Negative Predictors of Survival Long Term Giuseppe Sapienza1, Teresa Lamparelli2, Alida Dominietto2, Anna Maria Raiola2, Carmen Di Grazia2, Francesca Gualandi2, Simona Sica3, Elisabetta Metafuni3, Emanuele Angelucci2, Andrea Bacigalupo3 P584 Prevalence of Bronchiolitis Obliterans Syndrome (BOS) Following Allogeneic Hematopoietic Stem Cell Transplant (ALLOHSCT) in The US, Europe and Japan Emilie Hofstetter1, Dominik Kappeler2, Noreen Roth Henig3, Anne Bergeron4 P585 Netupitant-palonosetron (NEPA) to Prevent Chemotherapy-induced Nausea and Vomiting (CINV) in Multiple Mieloma (MM) Patients Receiving High-Dose (HD) Melphalan and Autologous Stem Cell Transplantation (ASCT) Vincenzo Apolito1, Simone Ferrero1, Mattia D’Agostino1, Giusy Cetani1, Francesca Bonello1, Federica Martella1, Danilo Faraci1,2, Sara Butera1,2, Giuseppe Lanzarone1, Alessandra Larocca1, Stefania Oliva1, Lucia Brunello1,2, Luisa Giaccone1,2, Mario Boccadoro1, Dario Ferrero1, Benedetto Bruno1,2, Marco Cerrano1,2 P586 Most Frequent Late Effects after Allogeneic Hematopoietic Stem Cell Transplantation iIn Adult Acute Lymphoblastic Leukemia does not seem to Worsen Performance Status Irati Ormazabal Velez1, Marina Quesada Sánchez2, Angela Figuera Álvarez1,2 P587 Involving Stem Cell Transplant Patients and Their Families to Improve The Anthony Nolan my Transplant Tracker App Jonathan Kay1, Julia Laflin2, Vasileios Karageorgos2, David Hoskins2, Hayley Leonard1, Tom Bishop1, Clare Cooper-Hammond2, Laura Phillips1, Chiara Di Biase1 P588 Early Menopause and Risk Factors after Allogeneic Hematopoietic Stem Cell Transplantation in Premenopausal Adult Women Yoo Jin Lee, Jeong Sook Kim, Jae-Cheol Jo, Jaekyoung Cheon, SuJin Koh, Young Joo Min, Kukju Kweon, Sang-Hyuk Park, Jun-Woo Ahn, Yunsuk Choi P589 Clinical Characteristics and Management of Late Relapse of Acute Myeloid Leukaemia more than Five Years after Allogeneic Stem Cell Transplantation Shafqat Inam, Shu Wong, Michelle Kenyon, Victoria Potter, Austin Kulasekararaj P590 Following up with Adult Patients with Acute Lymphoblastic Leukemia Following 5+ Years of Allogeneic Hematopoietic Stem Cell Transplantation: A Single Center Experience Yuta Katayama, Ryouta Imanaka, Koji Iwato, Tatsuya Terasaki, Takuya Nunomura, Fumiaki Jinnouchi, Takeshi Okatani, Kohei Kyo, Mitsuhiro Itagaki, Shinya Katsutani, Tsuyoshi Muta, Hideki Asaoku P591 Low Back Pain and Laser Acupuncture in Patients Undergoing Haematopoietic Stem Cells Transplantation Rodrigo Ramos1, Michele Canena2, Gilberto Souza1, Marcia Valentim1, Jefferson Caldeira1, Paula Oliveira1, Niágara Barreto3 P592 Effects of Controlled Exercise on Patients Undergoing Hematopoietic Stem Cell Transplantation Rodrigo Ramos1, Niágara Barreto2, Michele Canena3, Gilberto Souza1, Márcia Valentim1, Paula Oliveira1 P593 Development of Guillain-barré-like Syndrome in a Patient with Acute Lymphoblastic Leukemia after Haploidentical Hematopoietic Stem Cells Transplantation Natalia Zorina, Natalia Minaeva, Marina Khorobrykh, Philip Sherstnev, Alexey Lyanguzov, Konstantin Vetoshkin, Sergey Utemov, Natalia Isaeva P594 Haploidentical Donor or Unrelated Donor for Infants with Severe Combined Immunodeficiency? Su Han Lum, Zohreh Nademi, Terry Flood, Andrew Cant, Sophie Hambleton, Andrew Gennery, Mary Slatter P595 Use of Ruxolitinib in Pediatric Patients with Steroid-Refractory Graft-versus-host Disease (GVHD) Marco Becilli, Pietro Merli, Daria Pagliara, Federica Galaverna, Mattia Algeri, Stefania Gaspari, Emilia Boccieri, Roberto Carta, Annalisa Ruggeri, Franco Locatelli P596 Hematopoietic Stem Cell Transplantation (HSCT) in Refractory Cytopenia of Childhood (RCC): Improved Engraftment Following a Treosulfan Based Conditioning Regimen Brigitte Strahm1, Ayami Yoshimi1, Miriam Erlacher1, Michael Albert2, Jochen Buechner3, Birgit Burkhardt4, Barbara De Moerloose5, Kristian Kallay6, Peter Lang7, Ricardo Masetti8, Roland Meisel9, Herbert Pichler10, Ansgar Schulz11, Karl-Walter Sykora12, Dominik Turkiewitz13, Franco Locatelli14, Charlotte Niemeyer1 P597 Pharmacokinetics of Active ATG Impacts T-cell Recovery after TCRαβ/CD19-Depleted HSCT in Paediatric Patients Lisa V.E. Oostenbrink1, Alexandra Laberko2, Elvira Sultanova2, Els C.M. Jol-van der Zijde1, Anja M. Jansen-Hoogendijk1, Carly Vervat1, Dmitry Pershin2, Maria Fadeeva2, Ivan Vladimirov2, Robbert G.M. Bredius1, Maarten J.D. van Tol1, Michael Maschan2, Marco W. Schilham1, Dmitry Balashov2, Arjan C. Lankester1 P598 Haploidentical Hematopoietic Stem Cell Transplantation in Pediatric Patients: A Multicentre Study from India Sunil Bhat1, Revathi Raj2, Arun Danewa1, Gaurav Kharya3, Biju George4, Mehdi Intezar5, Neha Rastogi6, Vikram Mathews4, Badiger Shobha1, Atish Bakane3, Ramya Uppuluri2, Satya Prakash Yadav6 P599 Immune Recovery and long-term Survival Following Haploidentical T And B Cell Depleted Stem Cell Transplantation - Influence of Various ATG Doses Claus-Philipp Maier1, Friedhelm Schuster2, Bernd Gruhn3, Roland Meisel2, Patrick Schlegel4, Anne-Marie Lang4, Wolfgang Schwinger5, Tobias F. Feuchtinger6, Holger Martinius7, Rupert Handgretinger4, Peter Lang4 P600 Outcomes of Haploidentical vs Matched Unrelated Hematopoietic Stem Cell Transplantation with Post-Transplant Cyclophosphamide (PTCY) in Pediatric High-Risk ALL and AML in 1st and 2nd CR Olesia Paina, Zhemal Rakhmanova, Polina Kozhokar, Anastasia Frolova, Lubov Tsvetkova, Kirill Ekushov, Inna Markova, Sergey Bondarenko, Elena Babenko, Aleksandr Alyanskiy, Ildar Barkhatov, Elena Semenova, Ludmila Zubarovskaya, Boris Afanasyev P601 P602 P603 Landmark Analysis in High Risk Childhood Acute Leukemia Patients Undergoing Allogenic Hematopoietic Stem Cell Transplantation. A Retrospective Study Blanca Molina Angulo, Marta Gonzalez Vicent, Ivan Lopez Torija, Ana Castillo, Manuel Ramirez, Miguel Angel Diaz Perez P604 Defibrotide in Hematopoietic Stem Cell Transplant: An Study of Grupo Español De Trasplante Hematopoyetico (GETH) And Grupo Español De Trasplante De Medula En NiñOS (GETMON) Marta Gonzalez Vicent1, Cristina Diaz de Heredia2, Jesus Gonzalez de Pablo3, Blanca Molina3, Alexandra Regueiro4, Antonio Perez5, Pilar Palomo6, Laura Prieto7, Estefania Garcia8, José María Fernández9, Ariadna Pérez10, María José Jiménez11, Manuel Regueiro12, Carlos Vallejo13, Ana Isabel Gallardo14, Oriana López15, Ana Benito14, Julia Marsal16, Mónica Lopez17, Leyre Bento18, Isabel Badell19, Alexandra Pedraza20, Ana Jimenez21, Pedro Gonzalez22, Mi Kwon23, Lissette Costilla24, Cristina Belendez23, Albert Esquirol19, Ildefonso Espigado25, Esperanza Lavilla26, Miguel Angel Diaz27 P605 Nivolumab-based Therapy Prior to Hematopoietic Stem Cell Transplantation in Pediatric Hodgkin´s Lymphoma Andrey Kozlov, Asmik Gevorgian, Darya Zvyagintseva, Tatyana Iukhta, Ilya Kazantzev, Polina Tolkunova, Elena Morozova, Natalia Mihailova, Ludmila Zubarovskaya, Boris Afanasyev P606 School during and after Allogeneic HSCT : A Survey of Practices in Three European Countries Fanette Bernard1, Caroline de Pesters2, Claire Galambrun3, Mary Slatter4, Charlotte Jubert5, Nicolas Von der Weid6, Eva De Berranger7, Cecile Renard8, Ben Carpenter9, Benedicte Neven10, Fanny Rialland11, Jean-Hugues Dalle12, Persis Amrolia13, Marc Ansari1,2, Catherine Paillard14 P607 Haematopoietic Stem Cell Transplantation in Patients with Fanconi Anaemia: Experience of the Spanish Working Group for Bone Marrow Transplantation in Children (GETMON) Laura Murillo1, Marta González-Vicent2, Bienvenida Argilés3, Isabel Badell4, Antonia Rodríguez-Villa5, Mónica López6, Cristina Beléndez7, Ana Sastre8, Julián Sevilla2, Cristina Díaz de Heredia1,9 P608 The Role of Donor KIR Genotyping in Pediatric Hematopoietic Stem Cell Transplantation For Non-Malignant Disorders Livia Mariano1, Alice Bertaina2, Bing M. Zhang2, Karen Kristovich2, Marcelo Fernandez Vina2 P609 Single-center Experience of TCRαβ/CD19 Depleted Stem Cell Transplantation in Children with Fanconi Anemia Svetlana Radygina, Larisa Shelikhova, Irina Shipitsina, Yulia Skvortsova, Anna Vasilieva, Svetlana Kozlovskaya, Rimma Khismatullina, Anna livshits, Alexei Maschan, Michael Maschan, Dmitry Balashov P610 Detection of Recipient-specific α/β-T-cells during the Pre-engraftment Phase Does not Predict Graft Rejection in Patients after Haplosct: Preliminary Results of Single Centre Prospective Trial Ladislav Król1,2, Dominik Turkiewicz1,2, Stig Lenhoff1, Annika Hult1, Annika Kisch1, Mari-Louise Römbo1, Lisette Hollender1, Ingrid Øra1,2, Josefina Dykes1 P611 Improved Survival after MIBG Therapy in Combination with Megachemotherapy than after Stand-Alone Therapy in Children with Neuroblastoma - Polish Nation-wide Retrospective Study Marek Ussowicz1, Aleksandra Wieczorek2, Agnieszka Dłużniewska3, Anna Pieczonka4, Katarzyna Drabko5, Robert Dębski6, Jolanta Goździk3, Jacek Wachowiak4, Walentyna Balwierz2, Daria Handkiewicz-Junak7 P612 Use of RIC Regimens Combined with Tcrab Depletion and Posttransplant Cyclophosphamide in Pediatric Mismatched SCT Peter Lang, Michaela Doering, Anne-Marie Lang, Patrick Schlegel, Christian Seitz, Robin Fischer, Marina Schmidt, Martin Ebinger, Ursula Holzer, Ines Brecht, Rupert Handgretinger P613 The Role of HLA-DP Matching in Donor Selection for MUD-HSCT in Children with Hematologic Malignant Diseases Manuela Tumino1, Giulia Reggiani2, Chiara Mainardi2, Elisabetta Calore2, Antonio Marzollo2, Elisa Carraro2, Maria Vittoria Gazzola2, Roberta Destro2, Matteo Barioni2, Aurora Strano2, Marta Pillon2, Alessandra Biffi2 P614 Early Initiation of Cyclosporine-mycophenolate Plus Antithymocyte Globulin in HAPLO Transplant with Post-transplant Cyclophosphamide in Children: Low Incidence of Severe Acute GVHD with Encouraging Survival Angela María Trujillo Gaviria, Amado Jose Karduss U, Gloria Suarez, Angelica Cardona, Monica Ramirez, Jose Betancurt P615 Veno-occlusive Disease with Emphasis on Renal Manifestations in Pediatric Hematopoietic Stem Cell Transplantations: A Single Center Experience Aharon Gefen1, Shirley Pollack1, Irina Zeidman2, Neta Nevo1, Israel Eisenstein1, Daniella Magen1, Myriam Weyl-Ben Arush1 P616 Outcome after HSCT in Children with JMML from a Historical Point of View Mónica López Duarte1, Cristina Diaz de Heredia2, Marta Gonzalez Vicent3, Jose María Fernandez Navarro4, Isabel Badell Serra5, David Bueno Sanchez6, Ana María Galera Miñarro7, Jose María Perez Hurtado8, Antonia Pascual Martínez9, Jose Ramon Molina Hurtado10, Pilar Palomo Moraleda11, Cristina Belendez Bieler12, German Perez Vazquez13 P617 The Impact Recovery Absolute Lymphocyte Count at Days +21 on Outcome Allogeneic Stem Cell Transplantation in Pediatric ALL Lubov Tsvetkova, Olesia Paina, Zhemal Rakhmanova, Polina Kozhokar, Anastasia Frolova, Kirill Ekushov, Inna Markova, Sergey Bondarenko, Elena Babenko, Aleksandr Alyanskiy, Ildar Barkhatov, Elena Semenova, Ludmila Zubarovskaya, Boris Afanasyev P618 T-cell-rich Haploidentical Stem Cell Transplantation Improves Survival in Children with Acute Leukemia Relapsed after Allogeneic Transplantation Nobuhisa Takahashi, Shogo Kobayashi, Hideki Sano, Kazuhiro Mochizuki, Yoshihiro Ohara, Hitoshi Ohto, Kazuhiko Ikeda, Atsushi Kikuta P619 High Prevalence of Vitamin C Deficiency in a Large Paediatric Cohort Undergoing Hematopoietic Stem Cell Transplantation: A Single Centre Experience from 2003-2019 Rebecca Fisher, Jun Cai, Peter Shaw, Melissa Gabriel P620 Ex Vivo T Cell-depleted Haploidentical Hematopoietic Cell Transplantation for Pediatric Patients with Non-malignant Disease Ho Joon Im, Eun Seok Choi, Sung Han Kang, Jin Kyung Suh, Hyery Kim, Kyung-Nam Koh P621 Long-term Erythropoietic Recovery after Allogeneic Stem Cell Transplantation in Pediatric Patients: Host Determines Result Erik von Asmuth, Marco Schilham, Hein Putter, Alexander Mohseny, Arjan Lankester P622 Boost with CD34+ Cells for Poor Graft Function Treatment after HSCT in Paediatric Patients. A Multicenter Study Massimo Berger1, Francesco Saglio1, Maura Faraci2, Aracangelo Prete3, Franca Fagioli1 P623 Allogenic Stem Cell Transplantation for Fanconi Anemia: A Single Center Experience Eman Khattab, Abdelghani Tbakhi, Rula Najjar, Mayada Abu Shanap, Rawad Rihani, Hasan Hashem, Wafa Hdeib, Rawan Abed Alrahman, Du’A Darabseh, Nilly Hussein, Iyad Sultan P624 P625 First Allogeneic Hematopoietic Stem Cell Transplantation in RASGRP1 Deficieny Baris Kuskonmaz, Deniz Ayvaz, Fatma Visal Okur, Ilhan Tezcan, Duygu Uçkan Çetinkaya P626 Successful HSCT In Immune Disregolatory Diseases Vincenzo Pintabona1, Giulia Carracchia1, Elena Soncini1, Lucia Dora Notarangelo1, Richard Fabian Schumacher1, Marta Comini2, Alessandra Beghin2, Federica Bolda2, Walter Accini1, Arnalda Lanfranchi2, Fulvio Porta1,3 P627 Levofloxacin Based Prophylaxis in Children Receiving Allogeneic Hematopoietic Stem Cell Transplantation Does not Affect the Incidence of Acute GVHD and Bloodstream Infections Davide Leardini, Daniele Zama, Edoardo Muratore, Andrea Tozzi, Teresa Papaleo, Francesco Bacelli, Tamara Belotti, Elena Legnani, Arcangelo Prete, Andrea Pession, Riccardo Masetti P628 Rituximab-induced Secondary Hypogammaglobulinemia; Memorial Sloan Kettering’s 10-year Experience in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Patients Zahra Hudda1, Montserrat Cols Vidal2, Susan Prockop1, Richard O’Reilly1, Nancy Kernan1, Jayanta Chaudhuri2 P629 Effect of Serum Panel Reactive Antibodies on Allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Patients: A Single-center Experience Burcu Akıncı, Arzu Akçay, Fatma Demir Yenigürbüz, Didem Atay, Gülyüz Öztürk P630 Single Centre Experience with Stem Cell Transplantation for Inherited Bone Marrow Failure Syndromes Cristina Jercan1,2, Ana Maria Bica2, Letitia-Elena Radu1,2, Alexandra Ionete2, Ileana Constantinescu1,2, Carmen Calugaroiu2, Aurora Dragomiristeanu3, Anca Colita1,2 P631 Time Course and Impact of Body Weight Change Early after Allogeneic Stem Cell Transplantation in Children and Adolescents Kenji Kishimoto, Daiichiro Hasegawa, Sayaka Nakamura, Akihiro Tamura, Aiko Kozaki, Asturo Saito, Toshiaki Ishida, Takeshi Mori, Yoshiyuki Kosaka P632 Autologous Hematopoietic Stem Cell Transplantation for Pediatric High Risk Ewing Sarcoma, A Single Center Experience Hila rosenfeld keidar1, Amit dotan1, Sabina edelman1, Ronit elhasid1,2 P633 Conditioning for Retransplantation from the same Donor after Partial Autologous Reconstitution in Patients with PID: Immunosuppression is not Required Sarah Maria Bauer, Mehtap Sirin, Kerstin Felgentreff, Eva-Maria Jacobsen, Klaus-Michael Debatin, Ansgar Schulz, Manfred Hoenig P634 Tocilizumab Treatment for CRS in Haploidentical Stem Cell Transplantation: A Single Center Experience David Bueno1, Yasmina Mozo1, Luisa Sisinni1, Antonio Pérez-Martínez1,2 P635 Idiopathic Pneumonia Syndrome (IPS) After Peripheral Blood Stem Cell Transplantation from Unrelated Donor for Hurler Syndrome (Mucopolysaccharidosis Type 1) Successfully Treated with Etanercept and Steroids Kinan Kafa1, Claudia Bettoni da Cunha-Riehm2, Tayfun Güngör3, Jan-Henning Klusmann1 P636 Effect of Desensitization Protocol on Transplantation Success in Children with Anti-HLA Antibodies Özlem Arman Bilir1, İkbal Ok Bozkaya1, Mehtap Olcar Kanbur1, Melek Işık1, Klara Dalva2, Ali Kudret Adiloğlu1, Namık Yaşar Özbek1 P637 Outcome of Allogeneic Stem Cell Transplantation (ALLOHSCT) with Different Intensity Conditioning Regimens in Infant AML Zhemal Rakhmanova, Olesia Paina, Polina Kozhokar, Anastasia Frolova, Lubov Tsvetkova, Kirill Ekushov, Elena Babenko, Tatyana Gindina, Aleksandr Alyanskiy, Ildar Barkhatov, Elena Semenova, Ludmila Zubarovskaya, Boris Afanasyev P638 Higher Incidence of CMV and BKV Reactivation in Haploidentical Transplants Comparative to MUD or MSD Transplants - Single Centre Retrospective Analysis Cristina Jercan1,2, Ana Maria Bica2, Letitia-Elena Radu1,2, Alexandra Ionete2, Carmen Calugaroiu2, Ileana Constantinescu1,2, Aurora Dragomiristeanu3, Codruta Popa1,2, Anca Colita1,2 P639 Use of Polyclonal Igm-enriched Immunoglobulins for the Treatment of Septic Episodes in Children with Oncohematological Diseases Nicoletta Abram1, Valentina Baretta1, Federico Mercolini2, Gloria Tridello1, Margherita Mauro1, Simone Cesaro1 P640 Paediatric Bone Marrow Transplant Care on BMT versus NON-BMT Paediatric Wards Sinéad Greener1, Andrew Gennery1,2 P641 Non-white Hispanic Ethnicity as a Risk Factor for Sinusoidal Obstruction Syndrome after Hematopoietic Transplant Iván López Torija, Marta Gónzalez Vicent, Blanca Molina Angulo, Jesús González de Pablos, Miguel Ángel Díaz Pérez P642 Pneumatosis Intestinalis as a Rare Post-transplant Complication in Pediatric Patients Johanna Schepp, Mehtap Sirin, Kerstin Felgentreff, Carolin Grimm, Klaus-Michael Debatin, Ansgar Schulz, Manfred Hoenig P643 The Challenges and Outcomes Surrounding Intravesicular Cidofovir Administration - A Paediatric Pharmacy Perspective Poonam Lumb, Neil Tickner, Josu De La Fuente, Leena Karnik, Sandrine Bremathas P644 Haploidentical Stem Cell Transplantation (HAPLO-SCT) with Post-transplant-HD-Cyclophosphamide for Relapsed B-lymphoblastic Lymphoma (B-LBL) with MLL-rearrangement in 1 Y.O. Child: Clinical Case Sofia Matsiboh, Oleg Ryzhak, Nataliia Kavardakova, Julia Basaluk, Olena Kreminska, Tatiana Ponomarenko, Tomara Smolenska, Alexandra Sharamok, Svitlana Donska P645 Marrow Derived Cells Bring a Long Lasting Relief When Injected Intraarticularly to the Joints with Degenerative Arthritis Agata Borowik1, Arkadiusz Janusz1, Janusz Lange1, Danuta Sosnowska1, Emilia Jaskula1,2, Andrzej Lange1,2 P646 Successful KIR Alloreactive HSCT in a Child with Resistant Ewing Sarcoma Walter Accini1, Carmelita D’Ippolito1, Elena Soncini1, Giulia Carracchia1, Vincenzo Pintabona1, Lucia Dora Notarangelo1, Richard Fabian Schumacher1, Veronica Maria Folsi1, Chiara Gorio1, Marta Comini1, Alessandra Beghin1, Federica Bolda1, Raffaele Badolato1, Arnalda Lanfranchi1, Fulvio Porta1,2 P647 P648 P649 Impact of KIR on Patients with Lymphoid Diseases after T-cell Replete Haploidentical Hematopoietic Stem Cell Transplantation Yanmin Zhao, Fei Gao, Yibo Wu, Jimin Shi, Yi Luo, Yamin Tan, Jian Yu, Xiaoyu Lai, He Huang P650 Indications and Safety of Multiple Bone Marrow Harvests in Pediatric Donors for Matched Sibling Recipient Transplantation Amal Al-Seraihy, Viqaruddin Mohammed, Abdullah Aljefri, Ali Alahmari, Ibrahim Ghemlas, Hawazen Alsaedi, Awatif Alanazi, Rafat Jafri, Antonette Amao, Donya Qattan, Khaldoun Alshorman, Mouhab Ayas P651 Alternative Donor Hematopoietic Stem Cell Transplantation (HSCT) with Post-transplant Cyclophosphamide in Patients with Inherited Disorders Tatiana Bykova, Anna Osipova, Varvara Ovetchkina, Anna Dotcenko, Alexander Galimov, Alexander Alyanskiy, Ivan Moiseev, Alexander Kulagin, Elena Semenova, Ludmila Zubarovskaya, Boris Afanasyev P652 Young Male Donors may Result in Better Outcomes of Haploidentical Hematopoietic Cell Transplantation for Acute Leukemia with PT-Cy Mona Hassanein, Ahmed Kotb, Riad Elfakih P653 Donors of Peripheral Hematopoietic Stem Cells, our Experience for Last 10 Years Z. Bhuiyanova Ludvikova, Z. Gasova, M. Bohmova, M. Sloukova, P. Pecherkova, J. Soukupova, J. Vydra P654 Comparison of Transplant Outcomes and Economic Costs in Allogeneic Stem Cell Transplantation for AML and MDS Between The Different Type of Donors Yolanda Gonzalez Romero1, Joan Manuel Mora1, Sara Fernandez-Luis1, David Gomez-Lamas1, Jose Calvo-Sanchez1, Sergio Fernandez-Garcia1, Jose Luis Arroyo2, Aranzazu Bermudez1, Enrique Ocio1, Lucrecia Yañez1 P655 High Disease-free Survival of the Second Allogeneic Hematopoietic Stem Cell Transplantation with Donor Change and Mainly Reduced-intensity Conditioning in Relapsed Hematological Malignancies Yongqiang ZHAO, Yanzhi Song, Fan Yang, Zhihui Li, Min Jiang, Tong Wu P656 Epidemiological Study of Rare Antigens of the Main Histocompatibility Complex Among Hematopoietic Stem Cell Donors in Belarus Alena Hlaz1, Ihar Iskrou1, Olga Krasko2, Anatoly Uss1 P657 Impact of Donor-recipient Sex Mismatch in Patients Receiving Partial T-cell Depleted Allogeneic Stem Cell Transplantation for Hematological Malignancy: A Retrospective Monocentric Study Mitja Nabergoj, Maria Anastasiou, Sarah Morin, Yan Beauverd, Caroline Stephan, Carmen De Ramon Ortiz, Elif Mahne, Anna Petropoulou, Federica Giannotti, Christian Ayer, Benjamin Bruno, Laura Bounaix, Maria Mappoura, Thien-An Tran, Anne-Sophie Bessis, Eva Royston, Anne-Claire Mamez, Stavroula Masouridi-Levrat, Yves Chalandon P658 Haploidentical Donor Selection and Its Implications in Transplantation Outcome. Our Experience at Hudgc Dr. Negrín Cynthia Acosta Fleitas, Luisa Guerra Domínguez, Asunción Borrero Borrego, María Del Mar Perera Álvarez, Luz María González del Castillo, Leslie González Pinedo, Jezabel López Brito, Santiago Jiménez Bravo de Laguna, Teresa Molero Labarta P659 Outcome after Allogeneic Stem Cell Transplantation According to Donor Availability, Duration from Diagnosis to Transplant And donor-specific Parameters - A Single Center Analysis Jennifer Kaivers, Isabela Niculae, Elke Porbadnik, Christina Rautenberg, Esther Schuler, Jürgen Enczmann, Rüdiger Sorg, Johannes Fischer, Mustafa Kondakci, Rainer Haas, Ulrich Germing, Thomas Schroeder, Guido Kobbe P660 The Benefits of HLA-matched Related Donors for Patients Lacking HLA-identical Sibling in The Absence of Powerful Local Unrelated Registry in Countries with Prevalent Cousin Marriages Amir Ali Hamidieh1, Alieh Safari-Sharari1, Rashin Mohseni1, Mahnaz Jamee1,2, Zeynab Nikfetrat1, Leila Hejazipour1, Hamideh Keykani1, Fahimeh Jafari1, Pouria Salajegheh1, Maryam Behfar1 P661 Donor Age Influences the Graft-versus-host-disease-free and Relapse-free Survival after Allogeneic Stem Cell Transplant in Elderly Patients in Latin America Ana Lisa Basquiera1, Vera Milovic2, Mariano Berro3, Pablo García Rossi4, Maria Belen Castro1, Gonzalo Arirel Ferini1, Juan José Real2, Adriana Vitriu5, Alberto Gimenez Conca6, Georgina Bendek6, Sebastián Yantorno7, Juliana Martinez Rolón8, Alfredo Basso9, Sol Jarchum10, Amalia Cerutti11, Cinthya Silva12, Morgani Rodrigues12, Leandro Riera13, Jorge Alberto Arbelbide1, Nelson Hamerschlak12 P662 Withdrawl of Volunteer Donors from the International Registries: A Single Centre Experience Fulvio Porta1,2, Elena Soncini1, Giulia Carracchia1, Vincenzo Pintabona1, Walter Accini1, Marta Comini1, Alessandra Beghin1, Federica Bolda1, Arnalda Lanfranchi1 P663 Hepatitis E Virus (HEV) Contaminated Hematopoietic Stem Cell Graft in a Matched Unrelated Donor Transplantation Ksenia Boriskina, Per Ljungman, Lyda Osorio Fernandez, Stephan Mielke P664 A new BSA-based Threshold Predicts Optimal PBSC Collection in T-cell Depleted HLA-haploidentical Stem Cell Transplantation Pietro Merli1, Simone Biagini1, Elia Girolami1, Manuel Broglia1, Gianpiero Conflitti1, David Malaspina1, Mattia Algeri1, Federica Galaverna1, Annalisa Ruggeri1, Giovanna Del Principe1, Giovanna Leone1, Stefania Lazzaro1, Antonella Meschini1, Mauro Montanari1, Franco Locatelli1,2, Giuseppina Li Pira1 P665 Phase 1 Clinical Study of MGTA-145 in Combination with Plerixafor Shows Rapid Single-day Mobilization and Collection of CD34+ HSCS Without G-CSF John Dipersio1, Steven Devine2, Jonathan Hoggatt3, David Scadden4, Haley Howell5, Veit Schmelmer5, Jason Neale5, Michael Cooke5, Anthony Boitano5, Kevin Goncalves5, Glen Raffel5, Will Savage5, Dwight Morrow5, Pat Falahee5, John Davis5 P666 Depletion of αβ T-cells and B-cells Before HLA-haploidentical HSCT in Children with Malignant and Non-malignant Hematological Disorders: A Report of 473 Procedures Giuseppina Li Pira1, Elia Girolami1, David Malaspina1, Manuel Broglia1, Simone Biagini1, Gianpiero Conflitti1, Pietro Merli1, Federica Galaverna1, Annalisa Ruggeri1, Mattia Algeri1, Franco Locatelli1,2 P667 Acoustophoresis Enables the Label-free Separation of Distinct Subsets from Cultured Bone Marrow Stromal Cells Franziska Olm1, Hooi Ching Lim1, Katharina Schallmoser2, Dirk Strunk3, Thomas Laurell1, Stefan Scheding1,4 P668 Feasibility of Modified CD45RA Negative Donor Lymphocytes Infusion after Haploidentical Stem Cell Transplantation (HAPLO-SCT) with Post-transplantation Cyclophosphamide (PT-Cy) in Patients with Hematological Malignancies Stefania Bramanti, Filippo Magri, Federica De Paoli, Jasper Van Beek, Sarina Barbara, Inna Anatolievna Timofeeva, Jacopo Mariotti, Rossana Capizzuto, De Philippis Chiara, Domenico Mavilio, Armando Santoro, Enrico Lugli, Luca Castagna P669 Beyond Stem Cells- Does It Matter What´s in the Bag in Autologous Stem Cell Transplantation for Multiple Myeloma and Lymphoma? Holly Emms1, Dara Qadir1, Rowayda Peters1, Claire Wiggins2, Oliver Gittner2, Andy Drake1, Matthias Klammer1 P670 Lipegfilgrastim Combined with Chemotherapy was More cost-effective Than Pegfilgrastim In The Mobilization of CD34+ Cells in NHL Patients Anu Partanen1, Antti Turunen1,2, Jaakko Valtola1, Kaija Vasala3, Lasse Ågren4, Karri Penttilä5,6, Marja Pyörälä1, Taru Kuittinen1, Pentti Mäntymaa7, Jukka Peltonen2,7, Esa Jantunen1,2,4, Ville Varmavuo8 P671 Mobilization and Harvest of Peripheral Blood Stem Cells (PBSC) for Allogeneic Stem Cell Transplantation from 335 Pediatric Sibling Healthy Donors Malek Benakli, Nadia Rahmoune, Farih Mehdid, Mounira Baazizi, Dina Ait Ouali, Rachida Belhadj, Farida Harieche, Rose-Marie Hamladji, Redhouane Ahmed Nacer P672 Evaluation of Via FreezeTM Quad for Liquid Nitrogen-free CGMP-compatible Controlled-rate Freezing of Hematopoietic Progenitor Cell Grafts Bechara Mfarrej, Olivier Vicari, Sophie Thevenet, Kerjean Elodie, Claude Lemarie, Christian Chabannon, Boris Calmels P673 CD34 + Cell Subsets in Stem Cell Products and Their Relationship with Engraftment Kinetics Gizem Ertepe Kucukgode1, Senay Ipek2, Yasin Yildirim1, Melih Gaffar Gozukara3, Klara Dalva1, Guldane Cengiz Seval1, Sinem Civriz Bozdag1, Selami Kocak Toprak1, Meltem Kurt Yuksel1, Osman Ilhan1, Pervin Topcuoglu1 P674 Performance Qualification of LovoTM Medical Device for Washing and Concentrating 3 and More Hematopoietic Progenitor Cell Cryopreserved Bags Bechara Mfarrej, Guillaume Bouchet, Jerome Couquiaud, Lionel Regimbaud, Sophie Thevenet, Elodie Kerjean, Claude Lemarie, Christian Chabannon, Boris Calmels P675 From Work-up Request to Donation in Three Weeks: A Dedicated Registry Integrated Unrelated Donor Stem Cell Collection Center is Safe, Efficient and Convenient for Donors Isaac Yaniv, Tsippi Kestenbom, Sigal Manor, Bracha Zisser P676 Low-dose Cyclophosphamide + G-CSF is no More Effective than G-CSF Alone When Mobilizing and Collecting Stem Cells for Autologous Transplant in Multiple Myeloma Patients Antonio José Palma Vallellano, Rocío Zapata Bautista, Carmen Beltrán, Margarita Bendala, Ana R. Carranco, Miguel A. Castilla, Bianca Díaz, Juan Francisco Dominguez, Francisco Fernández, Encarnación Gil, Karol Gómez, Susana Ramírez, Juan Nicolás Rodríguez, María Solé, Pilar Velarde P677 First Interim Results of NIS Optimob - Nationwide Trial of Mobilization and Collection of Hematopoietic Stem and Progenitor Cells in Multiple Myeloma and Lymphoma Patients Max Bittrich1, Vladan Vucinic2, Matthias Grube3, Marcus Hentrich4, Maike de Wit5, Christian Kunz6, Bernd Metzner7, Andreas Humpe8, Andrea Stoltefuß9, Andreas Rank10, Kamran Movassaghi11, Alexander Kiani12, Cyrus Khandanpour13, Martin Schmidt-Hieber14, Frank Hartmann15, Nicolaus Kröger16 P678 The Impact of Plerixafor “on Demand” on the Hematopoietic Stem Cell (HSC) Collection, Product’s Quality and Engraftment Simona Maria Muggianu1, Maria Celentano1, Paolo Palmieri1, Cira Riccardi1, Salvatore Palmieri1, Mariangela Pedata1, Daniela Graziano1, Barbara Scarpati1, Raffaella Casaburi1, Claudio Falco1, Mirella Alberti1, Lidia Altomare1, Mario Toriello1, Assunta Viola1, Felicetto Ferrara1, Alessandra Picardi1,2, Michele Vacca1 P679 Elevated Serum Lactate Dehydrogenase after Stem Cell Mobilisation Predicts Successful Stem Cell Collection in Children Giao Lê, Noleen Comey, Michael Capra, Jane Pears, Cormac Owens, Aengus O’Marcaigh P680 Influence of the DMSO Wash Strategy on Adverse Reactions during Infusion of Hematopoietic Progenitors Irene García García, Gemma Moreno Jiménez, Anabelle Chinea Rodríguez, Paloma Ramos Oliva, Lourdes Ramos Oliva, Berta Mercedes Michael Fernández, Fernando Martín Moro, Adolfo Jesús Saéz Marín, Claudia Nuñez-Torrón Stock, Alejandro Luna De Abia, Ana Vallés Carboneras, Maria Concepción Tenorio Nuñez, Ana Jiménez Martín, Juan Marquet Palomanes, Pilar Herrera Puente, Jose Valentín García Gutierrez, Francisco Javier López Jiménez P681 Bone Marrow Donor Characteristics: Influence on Harvest Yield and Donor Recovery Eva Zoubek1, Jose Ros-Soto1, Richard Szydlo1,2, Adam Watson1, Catherine Burtlon1, Paul Johnson1, Ann O’Leary1, Chloe Anthias1,3 P682 Plerixafor Salvages Autologous Stem Cell Mobilisation Procedures in Myeloma Patients Previously Treated with Lenalidomide or Autologous HSCT: Cost-effectiveness of Upfront use should be Explored Paul Miller1, Janet Baker2, Crischi Magsipoc2, Joy Brennan2, Maria Mulligan2, Janet Wells2, Helen McDonald2, Kevin Boyd2, Martin Kaiser2, Mark Ethell2, Mike Potter2, Sandra Easdale2, Chloe Anthias2, Emma Nicholson2 P683 Effect of Shipping Time and Transport Conditions on the Viability of Cord Blood Leukocytes Izabela Zdolińska-Malinowska, Maciej Rojek, Michał Piątek, Dariusz Boruczkowski P684 Optimization of a Stem Cell Mobilization Strategy for Patients with Multiple Myeloma and Lymphoma Adolfo Sáez Marín, Alejandro Sanz Rupérez, María Concepción Tenorio Núñez, Sandra López González, Anabelle Chinea Rodríguez, Ana Vallés Carboneras, Ana Jiménez Martín, Kyra Velázquez Kennedy, Iván Mateos Pérez Cejuela, Claudia Núñez-Torrón Stock, Alejandro Luna de Abia, Irene García García, Fernando Martín Moro, Berta Mercedes Michael Fernández, Francisco Javier López Jiménez, Gemma Moreno Jiménez P685 Autologous Lymphapheresis for the Production of CAR-T Cells María Liz Paciello Coronel, Sara Redondo Velao, María Teresa Cedena, Alejandra Leivas Aldea, Antonio Valeri, Almudena García, Borja Andrades Velazquez, Desiré Sánchez Lozano, Encarnación Güemes Arce, Joaquín Martínez López P686 Red Blood Cell Depletion and/or Volume Reduction in Bone Marrow Processing: A Comparison of Two Methods Limor Horev azaria1, Yakov Sverdlov1, Michal Pearl-Yafe1, Orad Shemesh1, Alon Kalo1, Dana Greenfeld1, Jerry Stein1,2 P687 Correlation of Intra-operative Total Nucleated Count and Donor Characteristics with Final Allogeneic Bone Marrow Graft Characteristics and Recipient Clinical Outcomes Jacob Kalin, Anh Thy Nguyen, Benjamin Oshrine P688 Multicentre Evaluation of The HPC Modus (XN-20) for Timing the Harvest of Stem Cells from Peripheral Blood Kathleen Deiteren1, Jean-Philippe Defour2, Kornelia Hummel3, Holger Boysen3, Hans Salwender3, Jan-Dirk Studt4, Antoine Mairesse2, Katrien Vermeulen1, Dominik Heim5, Dimitrios A. Tsakiris5 P689 Impact of Change of Mobilisation Method on Adequacy of Stem Cell Collection in Multiple Myeloma Patients - Single Centre Experience Valarmathi Anandhan, Emma Searle, Jaya Sudhir, Alberto Rocci P690 Two Different Plerixafor Stem Cell Mobilization Strategies. A Multicenter Experience Carmen Albo López1, Concepción Andon2, Dolores Vilariño3, Esperanza Lavilla4, Julio Del Río5, Cristina Fonte1, Angeles Cobas4 P691 Autologous Peripheral Blood Stem Cells (PBSCS) Mobilization and Collection-princess Noorah Oncology Center Experience, Kamc - Jeddah - Saudi Arabia Mona Najib1,2, Ahmed Alsaeed2,3,4, Ihab Hemaidi2,3,4, Sameer Al Amoudi2,3,4, Mohammed Mohammadi1,2,4 P692 Review of Plerixafor use in a Tertiary Paediatric Oncology Centre Eileen Butler, Noeleen Comey, Dr Cormac Owens P693 Leukocytapheresis - One Technique, Diverse Opportunities in the Therapy of Patients Zdenka Gasova1, Zdenka Bhuiyan-Ludvikova2, Martina Bohmova2, Marketa Sloukova2, Pavla Pecherkova2, Jan Vydra2 P694 Impact of HLA-mismatch on Outcomes after Unrelated Bone Marrow Transplantation in Pediatric Patients: A Retrospective Analysis by The JSHCT HLA Working Group Itaru Kato1, Hirotoshi Sakaguchi2, Shunichi Kato3, Maho Sato4, Maiko Noguchi5, Nao Yoshida2, Masami Inoue4, Yoshiko Hashii6, Ken Tabuchi7, Yoshiko Atsuta8, Satoko Morishima9, Junya Kanda1 P695 Title: Clinical Impact of Donor Epitope-specific HLA Antibodies and Third-party HLA Antibodies in Haploidentical Hematopoietic Cell Transplantation Michiko Taniguchi, Dongyun Yang, Salman Otoukesh, Haris Ali, Shukaib Arslan, Chatchada Karanes, David Snyder, Guido Marcucci, Stephen J. Forman, Ryotaro Nakamura, Auayporn Nademanee, Ketevan Gendzekhadze, Monzr M. Al Malki P696 The Use of Post-transplant Cyclophosphamide (PT-Cy) in Unrelated Umbilical Cord Blood Transplantation Patrizia Chiusolo, Andrea Bacigalupo, Simona Sica, Sabrina Giammarco, Elisabetta Metafuni, Alessia Di Giovanni, Silvia Bellesi, Monica Rossi, Gessica Minnella, Maria Bianchi, Giovanna Valentini, Luciana Teofili P697 Comparative Study of Haploidentical Transplant Followed by Post-transplant Cyclophosphamide and Selective Ex Vivo T-cell Depletion vs Unrelated Cord Blood Transplant for Adults with Haematological Malignancies Yin Jie Koh1, Ian Wu1, Yeh Ching Linn2, Lip Kun Tan1, Michelle Poon1, Liang Piu Koh1 P698 Use of G-CSF Mobilized Bone Marrow Grafts in HLA-haploidentical Bone Marrow Transplantation (BMT) with Post-transplantation Cyclophosphamide (PT-Cy) Decreases Risk of Severe Acute GVHD Nadira Durakovic1,2, Zinaida Peric1,2, Lana Desnica2, Zorana Grubic3, Lucija Romić4, Ranka Serventi-Seiwerth2, Radovan Vrhovac1,2 P699 CMV-specific Functional Immune Reconstitution is Slower after Umbilical Cord Blood Compared with Matched Sibling Donor Hematopoietic Cell Transplantation Nelli Bejanyan1, Irina St Louis2, Hesham Mohei2, Qing Cao2, Najla El Jurdi2, Claudio Brunstein2 P700 Reduced Intensity (RIC) vs Myeloablative Conditioning (MAC) in Cord Blood Transplantation for AML (40-60 Years) Across Mismatched HLA Barriers - Analysis by Ctiwp/eurocord of EBMT Vipul Sheth1, Fernanda Volt2, Jaime Sanz3, Laurence Clement4, Jan Cornelissen,5, Didier Blaise6, Jorge Sierra7, Mauricette Michallet8, Riccardo Saccardi9, Eliane Gluckman2, Christian Chabannon10, Annalisa Ruggeri2,2,11 P701 Cost of Hematopoietic Stem Cell Transplantation in the Real World: An Analysis using The Japanese National Database Mizuki Watanabe, Shosuke Ohtera, Junya Kanda, Shusuke Hiragi, Tomohide Iwao, Tomohiro Kuroda, Akifumi Takaori-Kondo, Genta Kato P702 Association Between the Dose of CD3+ and CD34+ Cells in the Graft and Post-transplant Outcomes Tomoe Ichiki, Tatsunori Goto, Yosuke Domon, Kohei Ishigiwa, Kenichiro Takeda, Motohito Okabe, Yuka Kawaguchi, Rena Matsumoto, Marie Ohbiki, Masahide Osaki, Takanobu Morishita, Yukiyasu Ozawa, Koichi Miyamura P703 Hematopoietic Stem Cell Transplantation from a Related Donor with HLA-1 Antigen Mismatch in the Graft-versus-Host Direction using Low-dose Anti-thymocyte Globulin: Multicenter Phase II Trial Junya Kanda1,2, Toshihiko Ando3, Shun-Ichi Kimura2, Shin-Ichiro Fujiwara4, Kazunori Imada5, Shin Fujisawa6, Takayoshi Tachibana7, Yoshiko Atsuta8,9, Yoshinobu Kanda2,4 P704 Intra-bone Cord-blood Transplant of Unwashed Units with ATG-free and Sirolimus-based GVHD Prophylaxis: Fast Immune-reconstitution and Long-term Disease Control in 22 Patients with High-risk Diseases Fabio Giglio1, Angelica Barone2, Raffaella Greco1, Elisabetta Xue1, Matilde Zambelli1, Cristina Parisi1, Raffaella Milani1, Teresa Daniela Clerici1, Simona Piemontese1, Francesca Lorentino1, Sarah Marktel1, Rosamaria Nitti1, Lorenzo Lazzari1, Carmine Liberatore1, Magda Marcatti1, Consuelo Corti1, Massimo Bernardi1, Maria Teresa Lupo-Stanghellini1, Fabio Ciceri1,2, Jacopo Peccatori1 P705 Mesenchymal Stem/stromal Cell Production Compliant with Good Manufacturing Practice: Comparison Between Bone Marrow and Wharton’s Jelly Caroline Laroye1,2,3, Mélanie Gauthier1,2,3, Hélène Antonot1, Véronique Decot1,2,3, Loïc Reppel1,2,3, Danièle Bensoussan1,2,3 P706 Efficient DMSO Removal and High Cell Recovery with Lovo Cell Processing System in HPC-a Concentrates: A Single Centre Experience Maria Bianchi1, Nicoletta Orlando1, Caterina Giovanna Valentini1, Fernando Scavone1, Silvano Rovardi1, Fabio Del Mondo1, Sabrina Sparnacci1, Luciana Teofili2

29 August - 1 September, 2020 ● Virtual Meeting

Modified and published with permission from https://www.ebmt.org/annual-meeting

Sponsorship Statement: Publication of this supplement is sponsored by the European Society for Blood and Marrow Transplantation. All content was reviewed and approved by the EBMT Committee, which held full responsibility for the abstract selections.

Acute leukaemia

P001 Allogeneic Stem Cell Transplantation for AML Patients with Runx1 Mutation in First Complete Remission: A Study on behalf of the ALWP of the EBMT

Johanna Waidhauser1, Myriam Labopin2,3, Jordi Esteve4, Nicolaus Kröger5, Jan Cornelissen6, Tobias Gedde-Dahl7, Gwendolyn Van Gorkom8, Jürgen Finke9, Montserrat Rovira4, Nicolaas Schaap10, Eefke Petersen11, Dietrich Beelen12, Donald Bunjes13, Christoph Schmid1, Arnon Nagler14, Mohamad Mohty2,3

1Universitiy Medical Center Augsburg, Augsburg, Germany, 2EBMT Paris Study Office, Hôpital Sain-Antoine, Paris, France, 3INSERM UMR 938, Sorbonne University, Paris, France, 4Hospital Clinic, Barcelona, Spain, 5University Hospital Eppendorf, Hamburg, Germany, 6Erasmus MC Cancer Institute, University Medical Center, Rotterdam, Netherlands, 7Oslo University Hospital, Oslo, Norway, 8University Hospital Maastricht, Maastricht, Netherlands, 9University of Freiburg, Freiburg, Germany, 10Nijmegen Medical Centre, Nijmegen, Netherlands, 11University Medical Center Utrecht, Utrecht, Netherlands, 12University Hospital Essen, Essen, Germany, 13Universitätsklinikum Ulm, Ulm, Germany, 14Chaim Sheba Medical Center, Tel Aviv University, Tel-Hashomer, Israel

Background: Acute myeloid leukemia with RUNX1 gene mutation (RUNX1+ AML) has been proposed as a provisional entity in the 2016 WHO classification. Inferior response rates and outcome after conventional chemotherapy have been detected in patients with RUNX1 gene mutation and accordingly, RUNX1+ AML is allocated in the unfavorable prognostic category of the 2017 European Leukemia Net classification. Following allogeneic stem cell transplantation (alloSCT), RUNX1 mutation was an unfavorable factor in one study in MDS/secondary AML, while data in de novo AML are scarce. In this retrospective study by the EBMT Acute Leukemia Working Party, we elucidate the prognostic value of RUNX1 mutation in patients undergoing alloSCT for AML in first complete remission (CR1).

Methods: Adults undergoing alloSCT for AML in CR1 from matched related or unrelated donors between 2013 and 2018 with complete information on conventional cytogenetics and RUNX1 mutational status were selected from the EBMT registry. Variables of interest were overall and leukemia-free survival (OS/LFS), GvHD/relapse free survival (GRFS), cumulative relapse incidence (RI), non-relapse mortality (NRM) and GvHD. Log rank test, Gray test and Cox regression models were used for statistical analysis.

Results: A total of 516 patients were included, 128 RUNX+ and 388 RUNX-, with >80% of both subgroups presenting as de novo AML. As expected, RUNX1+ patients rarely had co-mutations in NPM1 (6% vs. 26%, p=10-3), and showed a positive correlation with ASXL1 mutations (50% vs. 16%, p=10-4). Cytogenetic categories and other mutations (FLT3-ITD, CEBPA) were equally distributed between the two groups, as were age, donor and graft type, CMV, conditioning and T cell depletion (TCD).

Median follow-up was 16.4 (RUNX+) and 19.8 (RUNX-) months. 2y OS/LFS of the entire cohort were 64% [59-69]/57% [52-62], with no difference between RUNX1+ and RUNX1- patients either in univariate or multivariate analysis (2y OS: 67.9% [57.3-78.5] vs. 63.1%v[57.4-68.7]p=0.15; 2y LFS: 57.6% [46.4-68.7] vs. 57% [51.4-62.6], p=0.38]). RUNX1 mutation neither had any impact among patients with normal karyotype. Furthermore, no other outcome parameter was influenced by RUNX1 mutational status. Instead, multivariate analysis revealed age and donor type as risk factors for OS, LFS and NRM. Poor cytogenetic was associated with higher RI and inferior LFS/GRFS, in vivo TCD with a lower rate of aGvHD II-IV, cGvHD, and better GRFS. Among patients with available information, FLT3-ITD was an independent risk factor for relapse, LFS and GRFS. RUNX1 did not modify the role of FLT3-ITD.

Conclusions: Within the limits of a retrospective registry analysis, we could not find a negative influence of RUNX1 mutation on outcome after allogeneic SCT in CR1. Hence, transplantation in CR1 might overcome the unfavorable prognostic value of RUNX1 mutation and can be recommended as consolidation treatment in this entity.

Disclosure: Nothing to declare.

P002 Graft Failure after Unmanipulated haplo-hsct with pt-cy in Patients with Acute Myeloid Leukemia in Complete Remission, on behalf of the ALWP-EBMT

Annalisa Ruggeri1, Myriam Labopin2, Emanuele angelucci3, Didier Blaise4, Fabio Ciceri5, Yener koc6, Jose Luiz Diez-Martin7, Luca castagna8, Benedetto Bruno9, Zafer Gülbas10, Andrea Bacigalupo11, Arnon Nagler12, Mohamad Mohty13

1OPBG, Roma, Italy, 2EBMT ALWP Office, Saint Antoine Hospital, Paris, France, 3San Martino, Genova, Italy, 4Paoli-Calmettes Institute, Inserm CBT1409, Marseille, France, 5San Raffaele Hospital, Milano, Italy, 6BMT Unit, Antalya, Turkey, 7BMT Unit, Madrid, Spain, 8HUMANITAS Cancer Center, Milano, Italy, 9BMT Unit, Torino, Italy, 10BMT Unit, Anadolu, Turkey, 11BMT Unit, Rome, Italy, 12Sheba University Hospital, Tel Aviv, Israel, 13Saint Antoine Hospital, Paris, France

Background: Graft failure (GF) is a life threatening complication following hematopoietic stem cell transplantation (HSCT). Its incidence depends on multiple parameters including type of donor, HLA disparity, stem cell source, graft composition and conditioning regimen. Incidence of GF in T-cell-depleted haploidentical-transplantations (Haplo-HSCT) can reach up to 10-20%. The use of Haplo-HSCT with post-transplant-cyclophosphamide (PTCy) as graft-versus-host-disease (GVHD) prophylaxis is a new standard in the treatment of hematological diseases. Paucity of data exists on GF in Haplo-HSCT with-PTCy.

Methods: To evaluate the incidence and risk factors of GF after Haplo-HSCT with-PT-Cy, we analyzed 1270 adults with acute myeloid leukemia (AML) reported to ALWP-EBMT who received a first Haplo-HSCT from 2010-2018. GF was defined as neutrophil count lower than 500 micro/L at day+45, competing risk was death without engraftment.

Results: Disease status was CR1 in 73% of patients and CR2 in the remaining. Secondary AML was reported in 13.7%. Median follow-up is 22 months and median age at Haplo-HSCT 54 years. Stem cell source was bone marrow (BM) in 41.4% and 44.6% of patents received a myeloablative conditioning regimen (MAC) with TBF(thiotepa, Bulsulfan and Fludarabine) in 59%. PT-Cy in association with calcineurin inhibitors and MMF was the most frequent GVHD-prophylaxis. Cumulative incidence of GF was 6.6 % (95%CI:5.3-8.1), median time to engraftment was 19(1-45) days. Nine patients engrafted after day+45(47-79), 43 patients experienced primary GF and 41 died before day+45 with no sign of donor engraftment. Of the 43 patients with GF, 7 subsequently engrafted after day+45, 29 patients were rescued with a second HSCT. Overall 18 patients are alive at last fu, 2y OS being 32%. CI of engraftment was lower in patients transplanted for secondary AML (91% vs 94%, p=0.003) and was 95% in MAC versus 92.6% in RIC, p< 0.001. CI of day-100 grade II-IV and grade III-IV aGVHD was 29.1 % (95% CI: 26.5 - 31.6) and 10.4 % (95% CI: 8.7 - 12.2), respectively, and 2 years chronic and extensive GVHD was 31.6 % (95% CI: 28.6 - 34.6) and 11.5 % (95% CI: 9.5 - 13.7). At 2 years GRFS, LFS, and OS were 47.1 % (95% CI: 43.9 - 50.2), 55.8 % (95% CI: 52.7-59) and 61 % (95% CI: 57.9-64.1), respectively. Two-year CI of relapse and NRM were 21.2 % (95% CI: 18.7-23.8) and 23 % (95% CI: 20.4-25.6). Disease recurrence was the most common cause of death, with infections and GVHD being the most frequent transplant related causes. In multivariate analysis, factors independently associated with the risk of GF were: secondary-AML (HR 1.28, p=0.007), use of RIC (HR 1.32, p< 0.001), and use of BM (HR 1.21, p=0.002). RIC and adverse cytogenetic risk were associated with relapse and age, performance status and cytogenetic risk with OS.

Conclusions: Incidence of GF after haplo-HSCT with PT-Cy is lower than in T-cell depleted Haplo. Optimization of conditioning regimen and graft source should be considered for reducing the risk GF in Haplo-HSCT recipients using PT-Cy. Comparison of GF in the different platforms of GVHD prevention (PT-Cy and ATG) is warranted.

Disclosure: Nothing to declare.

P003 Implications of Novel Risks Scores (AML-DRG and AML-HCT-CR) in Allogeneic CD34+ Selected Graft Transplant Outcomes

Rosalia Alonso Trillo1,2, Marta Garcia Recio3, Martina Pennisi2,4, Christina Cho2, Sean M. Devlin2, Josel D. Ruiz2, Molly A. Maloy2, Ana Alarcon Tomas1, Nerea Castillo5, Richard J. Lin2, Ioannis Politikos2, Miriam Sanchez Escamilla6, Michael Scordo2, Gunjan L. Shah2, Juliet N. Barker2, Hugo Castro-Malaspina2, Boglarka Gyurkocza2, Parastoo B. Dahi2, Ann A. Jakubowski2, Esperanza B. Papadopoulos2, Doris M. Ponce2, Craig S. Sauter2, Brian C. Shaffer2, Roni Shouval2, Roni Tamari2, Marcel R. M. van den Brink2, James W. Young2, Sergio A. Giralt2, Miguel Perales2

1Hospital Puerta de Hierro Majadahonda, Majadahonda, Spain, 2Memorial Sloan Kettering Cancer Center, New York, NY, United States, 3Son Espases University Hospital, IdISBa, Palma de Mallorca, Spain, 4University of Milano-Bicocca, Milan, Italy, 5Hospital Vall d’Hebron, Barcelona, Spain, 6IDIVAL, Santander, Spain

Background: Several prognostic models to stratify allogeneic hematopoietic cell transplantation (allo-HCT) outcomes have been developed in recent years. Despite evidence that minimal residual disease (MRD) is an independent predictor of survival in patients with AML, MRD is excluded from most models. Two novel AML-specific disease scores that incorporate disease data, AML-specific disease risk group (AML-DRG) and AML-HCT-CR, have been shown to be predictive of survival in patients with AML who received an of unmodified HCT (Piyanuch et al. BBMT. 2019). T cell depletion (TCD) using ex vivo CD34 selection has been shown to decrease acute and chronic GVHD without increasing relapse in selected patients with AML, ALL and MDS, and results of a completed phase 3 trial are pending (NCT02345850). Our proposal is to validate both scoring systems in a cohort of patients who underwent ex vivo CD34 selected HCT.

Methods: We included 279 patients age > 18 years who underwent a first CD34+ selected allo-HCT for AML between 2008 and 2018 and calculated their AML-DRG and AML-HCT-CR scores. AML-DRG variables included: secondary AML, adverse European LeukemiaNet2017 genetic risk and MRD status. The AML-HCT-CR model also included HCT-CI score ≥ 3 and age ≥ 60 years. MRD was assessed pre HCT by flow cytometry and/or PCR or NGS as indicated. The primary outcome was survival (OS) and secondary outcomes were progression-free-survival (PFS), and incidences of non-relapsing mortality (NRM), and relapse.

Results: Median age was 55 years (range 19 to 73 years), 45.5% (n = 127) were females and median HTC-CI was 2. All patients received myeloablative conditioning. At time of HCT 20.8% patients had MRD+ status and 5.4% had active disease (Table 1). Median follow-up was 5.5 years (95% CI: 5.1-6.3). For the AML-DRG model, the 3-year OS in the low, intermediate, and high-risk groups were 65%, 52%, and 13%, respectively. PFS at 3 years were 63%, 43%, and 15% in the same groups. The OS predictive accuracy measured by c-statistic was 0.588. In the AML-HCT-CR model, patients in low, intermediate, high risk and very high risk had a 3 year OS of 72%, 58%, 39%, and 51%, respectively. The corresponding PFS at 3 years were 68%, 56%, 36% and 43%. The OS predictive accuracy measured by c-statistic was 0.615. Both scores significantly predicted relapse incidence (AML-DRG model p value= < 0.001; AML-HCT-CR model p value= 0.04), but AML-DRG model was not associated with NRM (p = 0.993).

Conclusions: The AML-DRG and AML-HCT-CR models are predictive of outcomes including OS, PFS, and relapse incidence in a large cohort of patients receiving TCD HCT with CD34+ selected allografts. These data should therefore lead to better patient selection for ex vivo CD34-selected allo-HCT. The predictive accuracy for both scoring systems is modest, however; and there remains a need for innovative models incorporating new clinical and genomic characteristics to achieve a scoring system with improved accuracy.

Disclosure:

Marta Garcia Recio, MD:

Janssen and Takeda Honorary

Ioannis Politikos, MD:

Funding from Angiocrine Bioscience, Inc.InvestigatorResearch: MerckInvestigatorResearch

Michael Scordo, MD:

Consultancy: McKinsey & CompanyConsultancy and Angiocrine Bioscience, Inc.Consultancy

Gunjan L. Shah, MD:

Funding JanssenInvestigatorResearch and AmgenInvestigatorResearch

Juliet N. Barker, M.B.B.S (Hons), FRACP Doctor:

Funding: Merck & CoInvestigatorResearch, AngiocrineInvestigatorResearch, MerckInvestigatorResearch, GamidaInvestigatorResearch,

Boglarka Gyurkocza, MD:

Actinium Pharmaceuticals Inc.nonemy institution receives research funding from Actinium Pharmaceuticals Inc.

Craig S. Sauter, MD:

Board, Honoraria and Research Funding: Spectrum PharmaceuticalsadvisorAdvisory, NovartisadvisorAdvisory, GenmabadvisorAdvisory, Precision Biosciencesadvisor and research fundsAdvisory

Board and Honoraria: Kite, a Gilead CompanyadvisorAdvisory, Gamida CelladvisorAdvisory, PfizeradvisorAdvisory, GSKadvisorAdvisory Board and Honoraria

Marcel R. M. van den Brink, MD, PhD:

Seres InvestigatorHonoraria, Intellectual Property Rights, Research Funding and Stocks

EveloHonorariaHonoraria

Honoraria: Jazz Pharmaceuticals, Therakos, AmgenHonoraria, Merck & Co. Inc, Magenta Therapeutics

Smart ImmuneInvestigatorStocks, JunoInvestigatorIntellectual Property Rights

DKMSChairmanAdvisory Board

Sergio A. Giralt, MD:

Consultancy: Amgen, Actinuum, Celgene, Johnson&Johnson, JAZZ pharmaceutical, Milteny, Takeda, Novartis, Kite and Spectrum Pharma.

Miguel Perales, MD:

Honoraria from Abbvie, Bellicum, Celgene, Bristol-Myers Squibb, Incyte, Merck, Novartis, Nektar Therapeutics, Omeros, and Takeda. He serves on DSMBs for Cidara Therapeutics, Servier and Medigene, and the scientific advisory boards of MolMed and NexImmune. He has received research support for clinical trials from Incyte, Kite/Gilead and Miltenyi Biotec. He serves in a volunteer capacity as a member of the Board of Directors of American Society for Transplantation and Cellular Therapy (ASTCT) and Be The Match (National Marrow Donor Program, NMDP), as well as on the CIBMTR Cellular Immunotherapy Data Resource (CIDR) Committee

P004 Downregulation of HLA-DR in Blasts of Patients with Acute Leukaemia Relapsing after Allogeneic Haematopoietic Stem Cell Transplantation

Memnon Lysandrou1, Maria Liga1, Eleni Gavriilaki2, Nikolaos Spyridis1, Alexandra Siorenta3, Eleni Kapsali4, Evgenia Verigou1, Vassiliki Douka2, Georgios Vartholomatos4, Ioanna Sakellari2, Achilles Anagnostopoulos2, Alexandros Spyridonidis1

1University of Patras, Rio, Greece, 2G.Papanicolaou Hospital, Thessaloniki, Greece, 3Hellenic National Centre of Histocompatibility, G. Gennimatas Hospital, Athens, Greece, 4University Hospital of Ioannina, Ioannina, Greece

Background: Relapse following allo-HSCT in patients with acute leukaemia remains to date a challenge in clinical practice and is associated with ominous prognosis. Identifying the mechanism leading to relapse will morph our therapeutic armamentarium in accordance with the underlying pathophysiology. Amongst recent studies, HLA Class II downregulation has emerged as a major mechanism of immune evasion after allo-HSCT in patients with AML. However, relapses of patients with ALL after allo-HSCT have not yet been studied in an identical manner. Our goal was to identify the downregulation of HLA-DR in blasts of patients with acute leukaemia after allo-HSCT using flow cytometry.

Methods: For this study, we retrospectively selected patients with a diagnosis of AML, ALL or MPAL who relapsed following allo-HCT for which raw flow cytometry data were available both at a pre-transplantation active disease and at relapse. Blast cells were gated, then analyzed based on their HLA-DR expression and a Mean Fluorescence Intensity was calculated for both timepoints (preMFI & relMFI). Analysis was performed using the FlowJo software (Version 10.5.3, FlowJo LLC). Normalisation of the MFI values was performed using the median HLA-DR MFI of blasts from 31 newly diagnosed acute leukaemias calculated as MFI/median. We defined HLA-DR Downregulation as the reduction of the normalized value at the time of relapse by at least 50% (preMFI-n/relMFI-n < = 0.5). Statistical analysis was performed using Graph Prism.

Results: We analyzed 16 patients (9 male, 7 female) median age of 44 years old (range 32-65) who underwent allo-HSCT for AML (n=12), ALL (n=3) and MPAL (n=1). Four patients received graft from a compatible sibling, 2 from an haploidentical donor and 10 from unrelated donors (7 from 7/8 HLA match, 3 from 8/8 HLA match). At the time of transplantation, 5 patients achieved CR1, 7 achieved CR2 and 4 had refractory disease. The median day of relapse was day 147 (60-405). Median preMFI and preMFI-n values were 10.035 (range 81-14818) and 1.01 (0.008-6.5) respectively, median relMFI and relMFI-n were 7.919 (69-62055) and 0.8 (0.007-6.2). In 8 out 16 paired samples we observed a reduction of the HLA-DR MFI and MFI-n by at least 50% at the time of relapse (median relMFI/preMFI 0.37, range 0.001-0.5). Moreover, HLA-DR downregulation was observed in 2 out of the 3 patients with ALL. There was no correlation between donor-recipient HLA incompatibility and HLA-DR downregulation (p=ns).

Conclusions: HLA-DR Downregulation represents a common mechanism of immune escape in acute leukaemias relapsing after allo-HSCT that accounts to 50% of our patients. We first describe this mechanism to be present in cases of ALL. Identifying this phenomenon in patients using flow cytometry provides valuable information concerning their treatment choices as they will obviously not benefit from donor lymphocyte infusions.

Disclosure: no disclosures

P005 Establishment of a National Stem Cell Transplant Clinical Trials Network: The UK Impact Partnership for Accelerated Cellular Therapies

David I Marks1, Shamyla Siddique2, Ronjon Chakraverty3, Aimee Jackson2, Victoria Potter4, Ram Malladi5, Andy Peniket6, Paresh Vyas7, Pamela Kearns2,8, Charles Craddock2,5

1University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom, 2University of Birmingham, Birmingham, United Kingdom, 3University College London Hospitals NHS Foundation Trust, London, United Kingdom, 4King’s College Hospital NHS Foundation Trust, London, United Kingdom, 5Queen Elizabeth Hospital Birmingham, Birmingham, United Kingdom, 6Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom, 7University of Oxford, Oxford, United Kingdom, 8NIHR Birmingham Biomedical Research Centre, Birmingham, United Kingdom

Background: Stem cell transplantation (SCT) plays a central role in the management of haematological malignancies and is increasingly utilised in the management of non-malignant disorders. Treatment toxicity and disease relapse remain major causes of treatment failure after both autologous and allogeneic SCT. In contrast to other areas of haemato-oncology where clinical practice is informed by large prospective randomised trials, transplant practice is largely informed by retrospective registry studies and local practice. Very few patients undergoing stem cell transplantation enter prospective randomised trials aimed at improving transplant outcome. Reasoning that major barriers to transplant trial delivery was the twin absence of resource for trial development and research nurse capacity within a large networked population, a 4-year pilot was established in 2017 to create a national transplant trials network in the UK.

Methods: The IMPACT partnership was established in 2017 and £3.4 million was awarded for a 4-year pilot by NHSBT and the charities Anthony Nolan and Leukaemia UK. Funding was awarded with the aim of recruiting at least 500 patients to 9 prospective trials with embedded sequential collection of clinical samples. The IMPACT grant funded a central Hub within a well-established Clinical Trials Unit which was responsible for clinical trial design, set-up, management, and publication of trial results. The Hub was linked with a Trials Network consisting of 10 major transplant centres each staffed by a dedicated IMPACT research nurse chosen through an independent peer review process. 12 additional UK centres were awarded Affiliate status. This effectively created a funded trials network able to recruit to transplant trials in a cohesive manner across a 20 million patient population.

Results: In the 24 months since its establishment the IMPACT network has received 28 proposals for transplant trials - 12 of which have been developed with expert statistical and clinical input from the IMPACT team through national workshops. Rapid feasibility assessments were performed for 10 of these trials. To date 7 trials have been submitted for independent peer review and six have been approved. Key transplant questions addressed include defining the optimal conditioning regimen in acute myeloid leukaemia and acute lymphoblastic leukaemia, studying the role of post-transplant maintenance and donor lymphocyte infusion (DLI) and optimising graft-versus-host disease prophylaxis. 3 trials have been opened with a mean of 12 months to set-up (range 8-18). In its first two years, the IMPACT network has randomised 183 patients to 3 trials. Of note, one trial - Pro-DLI, a randomised trial of DLI administration post-transplant-has fully recruited within 24 months - 8 months ahead of its scheduled target.

Conclusions: Investment in the IMPACT trials hub and network has rapidly transformed set-up and recruitment to prospective randomised trials in SCT within the UK. Key to this success has been its ability to accelerate and coordinate both trials set up and recruitment across a 20 million population. Further investment in such accelerated trial models is required across Europe if patient outcomes after stem cell transplantation are to be improved.

Clinical Trial Registry: N/A

Disclosure: Nothing to declare.

P006 A region-wide Retrospective Analysis of Outcome for Patients with Newly Diagnosed Acute Lymphoblastic Leukemia

Shuichi Ota1, Akio Shigematsu1, Ryoji Kobayashi2, Takeshi Kondo3, Tomoyuki Endo4, Yutaka Tsutsumi5, Hajime Kobayashi6, Yasutaka Kakinoki7, Satoshi Yamamoto8, Yuichi Konuma9, Takuto Miyagishima10, Tetsuyuki Igarashi11, Takanori Oda12, Hajime Sakai13, Toshimichi Ishihara14, Masahiro Yoshida15, Takahiro Nagashima16, Kazuya Sato17, Yuji Kanisawa18, Yoshihito Haseyama19, Yasuo Hirayama20, Mitsutoshi Kurosawa21

1Sapporo Hokuyu Hospital, Sapporo, Japan, 2 Sapporo Hokuyu Hospital, Sapporo, Japan, 3Aiiku Hospital, Sapporo, Japan, 4Hokkaido University, Sapporo, Japan, 5Hakodate Municipal Hospital, Hakodate, Japan, 6Obihiro Kosei Hospital, Obihiro, Japan, 7Asahikawa City Hospital, Asahikawa, Japan, 8Sapporo City General Hospital, Sapporo, Japan, 9Asahikawa Red Cross Hospital, Asahikawa, Japan, 10Kushiro Rosai Hospital, Kushiro, Japan, 11Tenshi Hospital, Sapporo, Japan, 12Hokkaido Medical Center for Child Health and Rehabilitation, Sapporo, Japan, 13Teine Keijinkai Hospital, Sapporo, Japan, 14Kin-ikyo Chuo Hospital, Sapporo, Japan, 15Steel Memorial Muroran Hospital, Muroran, Japan, 16Japanese Red Cross Kitami Hospital, Kitami, Japan, 17Asahikawa Kosei Hospital, Asahikawa, Japan, 18Oji General Hospital, Tomakomai, Japan, 19Tonan Hospital, Sapporo, Japan, 20Higashi Sapporo Hospital, Sapporo, Japan, 21National Hospital Organization, Hokkaido Cancer Center, Sapporo, Japan

Background: Recently, the prognosis for patients with acute lymphoblastic leukemia (ALL) has been improved by the introduction of tyrosine kinase inhibitors for Philadelphia chromosome-positive (Ph+) ALL patients and pediatric-inspired protocol for adolescent/young-adult (AYA) patients, and the indication of allogeneic stem cell transplantation (allo-SCT) at first complete remission (CR1) needs to be reassessed. We therefore retrospectively analyzed the impact of allo-SCT for patients with ALL in the era of TKIs and pediatric-inspired protocol for AYA.

Methods: Clinical data for 512 patients who were diagnosed as having ALL between 2007 and 2017 were collected from 21 centers in Hokkaido, Japan.

Results: The median age of the patients was 55 years (range: 15-84 years). Ninety-two of the patients were pediatric (0-14 years), 86 were AYA (15-35 years), 195 were adult (36-65 years) and 148 were elderly patients (66- years). Cytogenetic (G-banding) results were available in 486 patients. Three hundred forty-seven patients had abnormal karyotypes (AK), and 139 patients had normal karyotype (NK). The BCR-ABL fusion gene, including masked Ph+, was positive in 193 patients, and 181 (93.8%) of them were more than 36 years. Abnormalities of complex karyotype were seen in 94 of the patients. After a first remission induction therapy, 418 of 467 (89.5%) evaluable patients achieved complete remission (CR), and BCR-ABL positive patients showed better CR rate than those without BCR-ABL (93.7% vs. 87.4%, P=0.04). At the median follow-up of 1180 days (9-4049 days), overall survival (OS) was superior in patients with NK than those with AK (P=0.01), and BCR-ABL positive patients showed poorer OS than those without BCR-ABL (P=0.01). One hundred fifty-three patients received allo-SCT at CR1. The median age of those patients was 44, and BCR-ABL was positive in 53.9% of those patients. Allo-SCT did not improve overall survival (OS) for patients aged below 35 years. However, allo-SCT significantly improved OS in patients aged over 36 years with or without BCR-ABL (p< 0.01and p=0.03). In BCR-ABL positive patients, allo-SCT improved OS even for patients who achieved molecular remission after first course of chemotherapy (P=0.006). By subgroup analyses of the age groups (pediatric, AYA, adult and elderly), there were no difference of OS between NK and AK. In adult and elderly patients, OS was not different between BCR-ABL positive and negative patients, though in patients over 70 years, BCR-ABL positivity was associated with superior OS (Hazard ratio, 3.2; 95% confidence intervals, 1.04-4.78, P=0.02). In adult or elderly BCR-ABL negative patients, OS of patients with complex karyotype was inferior to those without complex karyotype. Among those patients who achieved CR1 after a first induction therapy, allo-SCT at CR1 was associated with superior OS [HR, 0.40; 95%CI, 0.39- 0.96, P=0.03].

Conclusions: Allo-SCT improved OS for patients with ALL aged over 36 years regardless of BCR-ABL positivity in the era of TKI. Allo-SCT at CR1 should be considered for adult BCR-ABL negative ALL patients, especially in patients who have received non-AYA chemotherapy regimen.

Disclosure: Shuichi Ota received the honoraria of lecture fee from Novartis.

P007 Pre-harvest Higher Donor Foxp3 Mrna and Lower CD4+ T Cell Concentration Predict Increased Risk of all Relapse after Myeloablative Hct with T-replete Bone Marrow Grafts

Niels Jacobsen1, Tina Frisch1, Niels Keiding2, Carsten Heilman1, Henrik Sengeløv1, Hans Madsen1, Hanne Marquart1, Mette Andersen1, Claus Christiansen1, Lars Ryder1

1Rigshospitalet University Hospital, Copenhagen, Denmark, 2University of Copenhagen, Copenhagen, Denmark

Background: The curative effect of HCT for acute leukaemia is due in part to the donor T cell-mediated graft-versus-leukaemia reaction (GvL). Yet, post-HCT relapse remains a major cause of treatment failure. Donor regulatory T cells expressing the transcription factor Foxp3 (Tregs) have been found to reduce donor T cell-mediated GvHD without compromising GvL.

Methods: We have obtained contrasting results by assessment of the level of Foxp3 mRNA expression by qPCR in pre-harvest donor blood CD4+ T cells in a consecutive series of 45 children and adults, median age 16.7 years, with ALL in 1st or 2nd CR who received myeloablative HCT using T-replete bone marrow grafts and post-HCT cyclosporine GvHD prophylaxis. Donor was an HLA identical sibling (N = 11) or an alternative, unrelated (N = 33) or other family (N = 1) donor. Anti-thymocyte globulin (ATG) was given during the pre-HCT conditioning to 28 of 34 patients with an alternative donor.

Results: Post-HCT relapse, defined morphologically, occurred in 17 patients median 363 days post-HCT. By Cox multivariate proportional hazard regression, the effect of donor blood Foxp3 mRNA level on relapse did not meet the proportionality assumption. Proportionality was achieved after dichotomy at the median time of relapse. No effect of donor Foxp3 mRNA level was demonstrated within the first 363 days after HCT. However, after day 363 a higher donor Foxp3 mRNA level was associated with an increased risk of relapse. Thus, seven of eight late relapses occurred in recipients from donors with pre-harvest Foxp3 mRNA level above the median. In contrast, a higher pre-harvest donor CD4+ T cell concentration was associated with a reduced relapse risk. In the multivariate regression analysis, a significant interaction between the pre-harvest donor CD4 T cell concentration and the use of ATG in the conditioning regimen was observed, indicating that the effect associated with donor CD4 T cells was modified by ATG, compatible with the notion that the effect associated with donor CD4 T cell concentration was abrogated in recipients who received conditioning including ATG. However, due to the small sample size it is premature to draw definite conclusions regarding the effect of ATG. Cumulative relapse incidence curves supported the Cox univariate and multivariate regression analysis. Furthermore, we observed a reduction of the probability of surviving in continuous CR associated with higher pre-harvest donor Foxp3 mRNA level and decreased pre-harvest donor CD4 T cell concentration.

Conclusions: A higher Foxp3 mRNA level in CD4+ T cells isolated from pre-harvest donor blood was associated with an increased risk of late relapse in patients with ALL after myeloablative HCT with T-replete bone marrow graft, suggesting that donor Tregs may inhibit GvL. In contrast, a higher pre-transplant donor CD4+ T cell concentration was associated with a reduced relapse risk. The donor CD4 T cell effect was restricted to patients who did not receive ATG during pre-transplant conditioning.

Disclosure: Nothing to declare.

NJ and TF contributed equally to this work.

P008 Epidemiology, Management and Economic Impact of Acute Myeloid Leukaemia and Myelodysplastic Syndrome in Spain: A Claims Database Analysis

Alicia Marsà1, Meritxell Ascanio1, Teresa Briones2, Josep Darbà3

1BCN Health Economics & Outcomes Research SL, Barcelona, Spain, 2Jazz Pharmaceuticals Iberia, Barcelona, Spain, 3Universitat de Barcelona, Barcelona, Spain

Background: To review epidemiology, management, use of resources, and costs of acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) via the evaluation of patient records.

Methods: Data were extracted from the Ministry of Health records via the Spanish claims database Minimum Basic Data Set. The database contains patient records compiled in 192 private and 313 public hospitals, covering all Spanish regions, between 1997 and 2015 for AML and between 2008 and 2015 for MDS, according to data availability. All records corresponding to AML and MDS were identified using the International Statistical Classification of Diseases and Related Health Problems version 9 (ICD9) codes: 205.00, 205.01, 205.02, 238.72, 238.73, 238.74, and 238.75. The costs of healthcare usage were calculated based on the mean costs of medical procedures as determined by the Spanish Ministry of Health, which exclude prescription medication.

Results: Overall, records of 39,568 patients with AML and 33,091 with MDS were analysed. In most cases, the AML type was not registered; 9% of the patients were registered as in remission and 1% in relapse at first entry within the study period. When MDS was specified, 18% of the patients were registered with low-grade MDS lesions, 8% with high-grade lesions, and 1% with 5q deletion. Mean age at AML diagnosis was 59 years (SD=21), whereas for MDS it was 78 years (SD=13). Patients were mostly between 70 and 89 years of age and predominantly male. In terms of disease management, of the 102,783 and 64,556 admissions registered for AML and MDS, respectively, 79% and 48% were attributed to haematology services and 58% and 83% of admissions were not scheduled; the median length of hospital stay was 17 days (IQR=26) for AML and 7 days (IQR=9) for MDS. Chemotherapy was the most common procedure performed in patients with AML (44%), followed by platelets transfusion (31%). Transfusion of packed cells (41%) and chest x-ray (20%) were the most common procedures in patients with MDS. There was an increase in bone marrow and hematopoietic stem cell transplants over time in Spain during the study period, from 171 in 1997 (1,494 patients) to 477 in 2015 (3,611 patients). Mean annual direct medical costs were measured throughout the study period and were €66,422,245 for AML and €42,635,313 for MDS; both displayed an increasing tendency over time, with the costs of AML increasing 3.7-fold between 1999 and 2011. Of these, €15,843,982 and €2,705,791 were directly linked to transplants. Mean annual costs per patient were €1,821and €1,288, respectively. In most admissions, (>96%) costs were financed by the Spanish social security system.

Conclusions: This retrospective study identifies patient characteristics, disease management, and health resource use related to AML and MDS treatment in Spain. AML and MDS represent a large burden for the National Spanish Healthcare System, with substantial costs incurred in secondary care settings. A large portion of these costs can be attributed to the increasing number of bone marrow and hematopoietic stem cell transplants.

Disclosure: Teresa Briones is an employee of and holds stock/stock options in Jazz Pharmaceuticals. The other authors have no conflicts of interest to declare.

P009 Pre-transplant Bone Marrow Cellularity and Blood Count Recovery are not Associated with Relapse or Survival Risk following Allogeneic Stem Cell Transplant for AML In Cr1

Igor Novitzky Basso1,2, Shiyi Chen1,2, Jeffrey Lipton1,2, Dennis Kim1,2, Auro Viswabandya1,2, Rajat Kumar1,2, Wilson Lam1,2, Arjun Law1,2, Zeyad Al-Shaibani1,2, Armin Gerbitz1,2, Ivan Pasic1,2, Jonas Mattsson1,2, Fotios Michelis1,2

1Princess Margaret Cancer Centre, Toronto, Canada, 2University of Toronto, Toronto, Canada

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) can be curative for acute myeloid leukemia (AML). Novel therapies may render patients’ bone marrows profoundly hypocellular and be associated with prolonged post-therapy pancytopenia. In individual patients, bone marrow cellularity (BMC) at pre-transplant assessment (PTP) and post-treatment pancytopenia (leading to classification as CR-incomplete [CRi] as per ELN 2017 criteria) may be a manifestation of disease persistence, and this clinical response to chemotherapy is concerning for treating physicians.

Methods: In the present retrospective study, we examined the impact of BMC and post-treatment blood count recovery on a single-center cohort of 342 patients who underwent HSCT for AML in CR or CRi from January 2013 until December 2018. Data was updated as of November 2019. Median age was 57 years (range 18-73). Disease status at PTP was first complete remission (CR1) in 86% and CR2 or beyond in 56% of patients. Myeloablative conditioning was administered to 31% of patients while 69% received reduced-intensity conditioning. In vivo T-cell depletion was given to 75% of patients. Donors were matched-unrelated, matched-related and haplo-identical related (200, 108 and 34). The median follow-up of survivors was 31 months (10-81).

For BMC, patients were grouped as scoring aplastic (< 10%), hypocellular, normocellular and hypercellular for age (22, 89, 174 and 52 patients respectively; 5 patients had missing data); BMC was assessed by established pathology criteria. For ELN response (ELNr) at PTP, all patients had BM blasts fewer than 5%, and those having neutrophils ≥ 1 and platelets ≥ 100 at PTP were deemed as CR, otherwise CRi (190 and 152 patients respectively). MRC cytogenetic risk as per Grimwade, et al 2010 was favorable=21, intermediate=227, adverse=66 and unknown=28.

Cox proportional hazard model was used to analyze the effects of variables on overall survival (OS) and Fine and Gray’s competing risk regression model was used to examine the effect of variables on cumulative incidence of relapse (CIR).

Results: OS of the whole cohort at 2y was 56.08%, while CIR was 20.31%. CIR for BMC groupings was aplastic 17.28%, hypocellular 22.60%, normocellular 19.63%, hypercellular 21.89%, p not significant (ns), see Figure 1; and for ELNr, CR 18.41%, CRi 22.69%, p ns. OS for BMC was aplastic 63.64%, hypocellular 49.39%, normocellular 56.34%, hypercellular 60.42%, p ns, and for ELNr, CR 56.97%, CRi 55.06%, p ns.

The distribution of MRC cytogenetic risk by BMC was not significantly different (p=0.26) nor was primary induction failure (p=0.759), HCT-CI (p=0.495) or usage of myeloablative conditioning vs reduced-intensity (p=0.988). ELNr CRi was more likely in BMC aplastic and hypocellular, than CR (p< 2.62e-8).

Multivariate analysis confirmed that neither BMC nor attainment of ELNr CR vs CRi had an impact on OS or relapse. Other factors such as age at transplant (p< 0.0001) and chronic GvHD (p=0.0003) influenced OS, while MRC cytogenetic risk (p=0.0009) and chronic GvHD (p=0.0011) affected relapse.

Conclusions: Neither ELN response status (CR vs CRi) nor bone marrow cellularity at pre-transplant assessment influence relapse post-transplant or OS. Hypocellularity and CRi should not be considered negative prognostic factors for post-transplant outcomes of AML.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (1)

[Figure 1: Cumulative incidence of relapse of bone marrow cellularity groupings.]

Disclosure: Nothing to declare.

P010 Immunotherapy Salvage for b-precursor Acute Lymphoblastic Leukemia Relapsing after Allogeneic Stem Cell Transplantation: A Retrospective Analysis by the Alwp of the Ebmt

Gesine Bug1, Myriam Labopin2, Ali Bazarbachi3, Eolia Brissot4, Stephen Robinson5, Alessandro Rambaldi6, Ben Carpenter7, Riccardo Saccardi8, Nicolaus Kröger9, Michael Potter10, Ibrahim Yakoub-Agha11, Laimonas Griskevicius12, Sebastian Giebel13, Arnon Nagler14, Mohamad Mohty4

1Goethe University Frankfurt, Frankfurt, Germany, 2EBMT Paris Study Office, Saint Antoine Hospital, INSERM UMR 938, Sorbonne University, Paris, France, 3American University of Beirut Medical Center, Beirut, Lebanon, 4Hopital Saint Antoine, Paris, France, 5Bristol Royal Hospital for Children, Bristol, United Kingdom, 6University of Milan and ASST Papa Giovanni XXIII, Bergamo, Italy, 7University College London Hospital, London, United Kingdom, 8Azienda Ospedaliera Universitaria Careggi, Firenze, Italy, 9University Hospital Eppendorf, Hamburg, Germany, 10Royal Marsden Hospital, London, United Kingdom, 11CHU de Lille, LIRIC, INSERM U995, Université de Lille, Lille, France, 12Vilnius University Hospital Santaros Klinikos, Vilnius, Lithuania, 13Maria Sklodowska-Curie Institute, Gliwice, Poland, 14Chaim Sheba Medical Center, Tel Hashomer, Israel

Background: Blinatumomab (BLINA) and inotuzumab ozogamicin (INO) have been used for relapsed and refractory B precursor acute lymphoblastic leukemia (ALL) with or without prior allogeneic hematopoietic stem cell transplantation (HSCT). In an international phase II study of 64 patients relapsing after HSCT and treated with blinatumomab, 1-year OS was 36% (Stein AS et al., BBMT 2019), which compared favorably with historical cohorts treated with chemotherapy, donor lymphocyte infusions or a 2nd HSCT (Spiridonidis A et al., Leukemia 2012). Our retrospective analysis evaluates (i) the impact of BLINA and INO as salvage therapy post-HSCT on OS in a larger patient cohort, (ii) the safety of additional DLI and (iii) the outcome of patients undergoing a 2nd HSCT.

Methods: We identified 133 adult patients median age 36 (range, 18-68) years with Philadelphia-negative ALL who were treated with either BLINA (n=93, 70%), INO (n=34, 26%) or both (n=6, 4%) within 180 days after their first molecular or hematologic relapse following a first HSCT, performed 2012-2018. Patients were transplanted in CR1 (53%), CR2 (34%) or CR3 (13%) from a matched sibling (32%), matched unrelated donor (55%), other relative (11%) or umbilical cord blood (2%) using myeloablative or reduced-intensity conditioning (77% and 23%, resp.). OS was calculated by Kaplan-Meier analysis. In the multivariate Cox analysis, patient age, CR1 at HSCT, donor type as well as factors associated with a p value < 0.10 in the univariate analysis were included.

Results: Relapse occurred at a median of 7.1 (range, 0.8-80.6) months post-HSCT and immunotherapy was started a median of 15 (range, 0-172) days after relapse. With a median follow-up of 14.8 (range, 7.7-28.3) months after immunotherapy, 1-year OS in all patients was 30.9% (95% CI: 21.7-40.2). In patients treated with either INO or BLINA, probability of 1-year OS was 20.4% (95% CI: 3.6-37.2) and 36.4% (95% CI, 25.2-47.6), resp. (Figure 1, p=0.041). Immunotherapy was applied as monotherapy (n=81, 61%) or associated with chemotherapy (n=52, 39%). Additional cellular therapy included DLI prior to (n=6, 5%) or subsequent to immunotherapy (n=24, 18%) and probability of 2nd HSCT within one year was 26% (95% CI: 18.8-33.8); these 39 patients had a 1-year OS of 42.4% (95% CI: 23.8-61.1) after 2nd HSCT. However, neither additional chemotherapy nor DLI or 2nd HSCT (as time-dependent variable) had a statistically significant effect on OS.

A total of 85 patients died, mostly from leukemia (n=53, 63%) or infection (n=20, 24%). Out of all 40 patients treated with INO, two were reported as dead due to SOS (both received a 2nd HSCT). In multivariate analysis, female gender (HR 0.45, p=0.001), sibling vs other donors (HR 0.52, p=0.009) and longer time to relapse (HR 0.96, p=0.012) proved to be independently associated with better OS.

Conclusions: In patients relapsing after an allogeneic HSCT, BLINA or INO immunotherapy was associated with 1-year OS rates of 20-36%. Additional DLI or subsequent HSCT seemed to be safe, but did not improve outcome.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (2)

[Fig. 1: Overall survival for patients receiving either INO or BLINA after relapse.]

Disclosure:

Gesine Bug: Pfizer: advisory board

Sebastian Giebel: Amgen: honoraria, advisory boards, travel grants; Pfizer: honoraria, advisory baords.

P011 Comparison of pre-transplant Comorbidity Indices in Acute Leukemia Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Zeynep Arzu Yeğin, Asena Dikyar, Lale Aydın Kaynar, Zübeyde Nur Özkurt, Münci Yağcı

Gazi University, Ankara, Turkey

Background: In 2005, Sorror et al introduced a new prognostic scale for the candidates of allogeneic

hematopoietic stem cell transplantation (allo-HSCT). Since then, several methods were developed to predict the risk of transplant related mortality. This retrospective study was designed to evaluate and compare the efficacy of the conventional and novel prognostic tools including hematopoeitic cell transplant (HCT)-comorbidity index (HCT-CI), HCT-CI/Age and HCT-composite risk (HCT-CR) indices.

Methods: A total of 215 acute leukemia (acute myeloid leukemia / acute lymphoblastic leukemia:

129/86) patients [median age: 37(18-71) years; M/F: 135/80] were included in this study. Medical records of the patients were retrospectively reviewed. Besides European Society for Blood and Marrow Transplantation (EBMT) score, Eastern Cooperative Oncology Group (ECOG) and Karnofsky scales; pre-transplant risk evaluation was performed using HCT-CI, HCT-CI/Age and HCT-CR, as previously described. Disease risk stratification was based on European Leukemia Net guidelines.

Results: Pre-transplant risk scales including EBMT [median score: 3(0-7)], HCT-CI [median score: 1(0-6)], HCT-CI/Age [median score: 1(0-7)] and HCT-CR [Low: 84(39.1%); Intermediate: 11(5.1%); High: 112(52.1%); Very high: 8(3.7%)] were evaluated as well as ECOG [median score: 1(0-4)] and Karnofsky scales [median score: 40(40-100)]. Pre-transplant disease status was first complete remission (CR1) in 150 patients (69.8%), CR2 in 29 patients (13.5%), >CR2 in 1 patient (0.4 %), partial remission in 10 patients (4.7%) and progressive disease in 25 patients (11.6%). A total of 162 HSCTs (75.3%) were related, 44(20.5%) were unrelated and 9(4.2%) were haploidentical transplants. Graft source was peripheral blood in 208 (96.7%) and bone marrow in 7 transplants (3.3%). Conditioning regimen was myeloablative in 158(73.5%) and reduced intensity in 57 patients (26.5%). Patients were divided into two subgroups based on HCT-CR. Group 1 represented low-risk patients, whereas Group 2 was composed of intermediate, high and very-high-risk patients. Sinusoidal obstruction syndrome was found to be more frequent in Group 2 (11.2% vs 2.8%; p=0.021). Prevalence of cytomegalovirus reactivation and acute/chronic graft versus host disease was similar in both groups. At a median 681(4-4774) days of follow-up, patients with low HCT-CR scores represented significantly higher probability of progression free survival (70% vs 53.5%; p=0.016) and overall survival (60% vs 41%;p=0.007) (Figure 1). In univariate analysis, HCT-CI (p=0.002), HCT-CI/Age (p=0.015), HCT-CR (p=0.009), EBMT (p=0.007), ECOG (p< 0.001), Karnofsky (p< 0.001) and C reactive protein levels had significant impact on survival. The significant impact of HCT-CI (p=0.018), HCT-CI/Age (p=0.008) and EBMT (p< 0.001) was confirmed in multivariate analysis.

Conclusions: To date, a variety of factors have been defined to determine allo-HSCT outcome. Both patient and disease related factors may have a role in predicting transplant related morbidity and mortality. This retrospective study underlines the importance of pre-transplant risk evaluation, although more experience is required to identify the better approach in order to improve our foresight in allo-HSCT setting.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (3)

[Figure 1. Impact of Risk Groups on Overall Survival]

Disclosure: Nothing to declare.

P012 Salvage use of venetoclax-based Therapy for Relapsed AML Post Allogeneic Hematopoietic Stem Cell Transplant

Joselle Cook, Maansi Joshi, Naseema Gangat, Animesh Pardanani, Ayalew Tefferi, Kebede Begna, Michelle Elliot, Aref Al-Kali, Mrinal Patnaik, Mithun V. Shah, William J. Hogan, Mark Litzow, Hassan B. Alkhateeb

Mayo Clinic, Rochester, MN, United States

Background: Relapsed acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplant (alloHCT) has a dismal prognosis. The efficacy of venetoclax (VEN) in post alloHCT relapse is understudied. Here we analyze the efficacy and application of VEN in this setting.

Methods: After IRB approval, retrospective analysis was performed for patients with de-novo or secondary AML who received alloHCT, and experienced relapse and were salvaged with VEN+ hypomethylating agent (HMA)/Cytarabine

Results: We identified 12 pts (50% female); median age 57 years (range 30 - 70). Five pts had de-novo AML (ELN adverse risk cytogenetics=2, intermediate risk cytogenetics =3) & 7 pts had secondary AML (ELN adverse risk=5, intermediate risk =2). The donor source was matched unrelated donor (n=7), matched related donors (n=2), haploidentical (n=2) and 1 umbilical cord transplant. 8 pts were in CR1, 3 pts were in CR2, and 1 with persistent residual disease at the time of transplant. Time from transplant to relapse was 196 days (range 77-1142). Time from alloHCT to VEN initiation was 378 days (range 104-1153). Median # of VEN cycles was 2 (1-5). Overall response rate (PR+CR) was 33% (n=4). Median time to CR was 82 days (range 38-125) with median duration of CR of 91 days (1 pt continuing in CR). The Grade 3 or 4 toxicities were infection (n=3) and neutropenia (n=5). Two pts had flare of GVHD on VEN requiring treatment: liver GVHD (n=1); skin, ocular GVHD (n=1). Full molecular information was available for 10 pts at diagnosis and in relapse post-alloHCT: 3 pts acquired TP53 mutations at relapse. Figure 1 outlines evolution of molecular abnormalities in the rest of the cohort, associated venetoclax doses and best responses. None of the pts experienced graft failure after salvage therapy. Estimated median overall survival after VEN was 73 days (Range 2- 403). Nine pts progressed on VEN, 2 pts received subsequent therapy [DLI (n=1), gemtuzumab ozogamicin (n=1)]; 8 of the 9 pts died. Median time from progression on VEN to death was 13 days (IQR 2-43). The most common molecular mutation among responders was TP53. Among 5 pts with TP53 mutation in our cohort; 3 achieved CR. Responders had a better survival compared to non-responders with a median OS 403 days vs 43 days respectively (Log-Rank p=0.011). Responders were naïve to HMA.

Conclusions: VEN-based therapy achieved an ORR of 33% in AML pts with post-transplant relapse, and prolonged survival in responders despite the presence of TP53 mutations. Our observations provides evidence that even in the context of post-transplant relapse with adverse mutations and limited treatment options, VEN- based therapy may be effective in inducing CR and possibly improves survival in responding patients.

Disclosure: Mark Litzow: Astellas: Research Funding; Amgen: Research Funding; Abbvie: Research Funding; Novartis: Research Funding; Sanofi: Consultancy; NewLink Genetics: Consultancy; Actinium: Research Funding; Pluristem: Research Funding; Servier: Consultancy

Mrinal Patnaik: Stem Line Pharmaceuticals.: Membership on an entity´s Board of Directors or advisory committees.

P013 Factors Predicting the Outcome of Allogeneic Stem Cell Transplantation in ph-negative Acute Lymphoblastic Leukemia

Olga Pirogova, Ksenia Afanaseva, Elena Morozova, Sergey Bondarenko, Inna Markova, Ivan Moiseev, Boris Afanasyev

First Pavlov State Medical University of St. Petersburg, Saint-Petersburg, Russian Federation

Background: In modern practice, a significant proportion of adult patients with acute lymphoblastic leukemia (ALL) undergo allogeneic bone marrow transplantation (allo- HSCT). The technology of allo- HSCT is improving, therefore it is necessary to evaluate the results and factors affecting the outcome of allo- HSCT in patients with ALL.

Methods: In the study included 191 patients with Ph-negative ALL with median age of 25 years (range, 18-61) who received allo-HSCT undergoing allo-HSCT from HLA-matched sibling (n=38), unrelated (n=123) or haploidentical (n=30) donor in R.M.Gorbacheva Memorial Institute between 2007 and 2019. Median follow-up time was 30 months (range, 2-148 months). By the time of allo-HSCT 41 (21,5%) of patients were in first remission, 80 (41,9%) in second remission, 26 (13,6%) in third or more remission, 44 (23%) in active disease. Reduced intensity conditioning (RIC) was performed in 90 patients (47,1%), myeloablative - in 101 patients (52,9%). Conventional calcineurin-based graft-versus-host disease (GVHD) prophylaxis was used in 90 patients (47,1%). Posttransplant cyclophosphamide(Cy) GVHD prophylaxis was used in 101 patients (52,9%).

Results: 5-years OS and EFS were 44,5% and 37,7%, accordingly, whereas 5-year incidence of relapse was 28,8%. Disease status was the main factor determining the results of transplantation in Ph-negative ALL patients. 5-years OS, EFS and relapse rate (RR) were 73,1%, 56,2%, 34,6%, 2,3% (HR=1,772, 95%Cl 1,46-2,151, p< 0,001) and 68,3%, 45%, 26,9%,2,3% (HR=1,764, 95%Cl 1,469-2,119, p< 0,001), 17,1%, 21,2%, 38,4%,47,7% (HR=2,528, 95%Cl 1,37-4,735, p< 0,001) in 1st, 2nd, 3d and active disease, respectively. RIC was associated with worse survival and increased transplant-related mortality (TRM), 5-years OS, EFS and TRM were 35,3% vs 52% (HR=1,64, 95%Cl 1,113-2,417, p=0,01), 28,8% vs 45% (HR=1,538, 95%Cl 1,069-2,213, p=0,02), 43,4% vs 25% (HR=1,817, 95%Cl 1,073-3,129, p=0,01) for RIC and MAC, respectively. TRM was higher after haplo than after unrelated and HLA-matched sibling allo-HSCT (50% vs 32,5% vs 23,7%, p=0,04). Positive minimal residual disease (MRD) before allo-HSCT determined high RR: 57,1% vs 7,1% (HR=8.119, 95%Cl 2,809-23,21, p< 0,001) for MRD positive and MRD negative. GVHD prophylaxis with posttransplant Cy significantly improved relapse-free and GVHD-free survival (GFRS) and reduced TRM. GFRS in1st, 2nd remission was 45,9% vs 10,8% (p< 0,001) patients for Cy and standard GVHD prophylaxis, respectively.

Conclusions: Allo-HSCT in patients with Ph negative ALL is low efficacy. MAC and posttrsnsplant Cy can improve results of Allo-HSCT in patients with Ph negative ALL. Achievement of MRD-negative status is crucial for the outcome thus the studies of bridging strategies are warranted.

Disclosure: Nothing to declare.

P014 Role of Chimerism and flow-cytometric Monitoring of Measurable Residual Disease(MRD) after Allogeneic Hematopoietic Stem Cell Transplantation(Allo-HSCT) in Predicting Relapse in Acute Myeloid Leukemia(AML)

Guldane Cengiz Seval, Eliz Bahar Ulas, Selami Kocak Toprak, Sinem Civriz Bozdag, Meltem Kurt Yuksel, Pervin Topcuoglu, Klara Dalva, Onder Arslan, Muhit Ozcan, Taner Demirer, Osman Ilhan, Hamdi Akan, Meral Beksac, Gunhan Gurman

Ankara University, Ankara, Turkey

Background: Allo-HSCT is a well-established postremission therapy in adults with AML with certain high-risk features. Two different techniques are currently available for posttransplantation surveillance of disease remission: characterization of posttransplantation chimerism and specific detection of MRD. In this retrospective single-center study, we have attempted to evaluate the impact of both chimerism and flow-cytometric MRD in relapse in a population of patients with AML who received an allo-HSCT.

Methods: A total of 65 patients with AML who achieved complete remission at day+100 after allo-HSCT were included. Chimerism and MRD analysis were performed routinely at 1, 3, 6, 9, 12 months after transplantation at our hematology laboratories. Flow cytometry analyses were done using the flow cytometry system FACSCalibur(BD Biosciences, San Jose, CA). Presence of donor chimerism was determined with microsatellite analysis of short tandem repeats(STR) by PCR(Qiagen Plex Plus Kit(100) PCR Assay, genemapper v3.2). We used our institutional database to evaluate details and characteristics of patients and transplant outcomes.

Results: A total of 194 consecutive patients with AML underwent allo-HSCT at our center between January 2010 and August 2019. For the present study, 65 patients (Female/male: 29/36; median age: 40.5 years(range: 18-67 years)) who had relapsed after Allo-HSCT were evaluated. Median follow up from allo-HSCT was 10.3 months(4-104 months). A total of 36(55.3%) patients underwent allo-HSCT from related donor while 29(44.7%) patients were transplanted from unrelated donors, respectively. The stem cell source was peripheral blood stem cells in 63 patients(96.9%). Fifty-patients received myeloablative conditioning, whereas 15 received a reduced intensity regimen. With regard to MRD status before transplantation, 37 of 65 patients were MRD-negative and 12 patients were MRD-positive and remaining 16 patients had active disease at the time of allo-SCT. After transplantation, 4 of the 37 patients who were initially MRD-negative changed to MRD-positive, whereas 9 of the 12 initially MRD-positive patients achieved at least temporary MRD negativity. Six of the patients with active disease achieved MRD negativity after Allo-HSCT. The relapse rate was 60% at 1 year and higher in the patients with mixed CD3 chimerism(n=20) compared with those with complete chimerism(n=45) at day+90. In addition, at time of relapse among study population only 33 patients had mixed CD3 chimerism. Patients with MRD positivity at day +28 after HCT had the highest incidence of relapse among all prognostic groups analyzed. The median time to hematologic relapse after detection of MRD relapse was median 62 days. Among all patients, 23 patients with MRD relapse and subsequent hematologic relapse also have been detected via a decrease in chimerism. Twenty-one patients had received DLI for MRD-positivity. During follow up 41 deaths were noted.

Conclusions: In light of recent advances in therapeutic options for post-transplantation relapse, improving our understanding of the available relapse prediction tools is becoming increasingly important. Our data presented here show the superiority of flow cytometric MRD over chimerism analysis to predict relapse after allogeneic stem cell transplantation. Therefore, further studies of larger randomized cohorts with high quality data management are required to clarify the role of post-transplantion MRD and chimerism in predicting relapsed in AML.

Disclosure: Nothing to declare.

P015 Sorafenib Prolonged Maintenance in flt3-mutated AML Post Transplantation

Carmine Liberatore1,2, Matteo Giovanni Carrabba1, Federica Ardizzoia1,2, Andrea Assanelli1, Carlo Messina1, Consuelo Corti1, Massimo Bernardi1, Jacopo Peccatori1, Fabio Ciceri1,2, Maria Teresa Lupo Stanghellini1

1IRCCS San Raffaele Scientific Institute, Milan, Italy, 2Vita-Salute San Raffaele University, Milan, Italy

Background: FLT3-mutated acute myeloid leukemia (AML) has high risk of relapse and still poor outcomes despite allogeneic stem cell transplantation (HSCT). Sorafenib is a multi-kinase inhibitor active in FLT3+ AML both in the pre- and post-HSCT setting.

Methods: from June 2017 to September 2019, 10 patients with advanced FLT3+ AML at transplantation received sorafenib as maintenance therapy after HSCT. Sorafenib was given off-label after provision of an informed signed consent and in the absence of alternative therapeutic options in all patients. Indications were both achievement of complete morphological remission (CR) and hematological engraftment. Exclusion criteria were active GvHD, infections and non-hematological toxicities. Sorafenib administration was prolonged until intolerance or disease progression.

Results: clinical-biological features at baseline and at sorafenib initiation are reported in Figure 1. Median time from HSCT to sorafenib initiation was 121 days (range 75-250). Nine out of 10 patients were still on GvHD prophylaxis. Sorafenib starting dosage ranged from 200 mg QD (6 patients) to 200 mg BID (4 patients) depending on clinical conditions and concomitant medications. Maximal dosage in our series was 200 mg BID in 6 patients and 200 mg QD in 4 patients.

Sorafenib was well tolerated: no hematological toxicity was observed. Most common grade I-IV adverse events (AE) were skin rash (20%), arterial hypertension (10%), sinus bradycardia (10%), diarrhea (10%), hyperbilirubinemia (10%) and peripheral neuropathy (10%). Most common grade III-IV AE was arterial hypertension (10%). Any patient died because of treatment. Four patients had dose reduction and 2 patients had temporary interruption of sorafenib because of AE.

Two patients developed acute GvHD grade 2 overall: no one had previous GvHD; one patient obtained complete remission with steroid treatment, the second completely resolved GvHD after second line therapy (infliximab). Three patients developed chronic GvHD: 2 classic and 1 overlap, maximal overall severity was moderate, 2/3 patients received ≥2 treatment lines.

After a median follow up of 15 months (range 6-36), all patients were alive. Nine patients were still on therapy while 1 patient finally stopped sorafenib after 4 days of administration due to a drug-related grade II sinus bradycardia.

Median duration of maintenance was 360 days (range 4-886). At last bone marrow evaluation, all patients were in CR and all evaluable patients (8/10) obtained MRD negativity.

Conclusions: post-transplantation maintenance with sorafenib proved feasible in FLT3+ AML: we did not reported major toxicity or adverse events. Sorafenib was effective both in preventing relapses and obtaining deep and durable remission.

Disclosure: Nothing to declare.

P016 Pulmonary Complications (PC) after Allogeneic Hematopoietic Stem Cell Transplantation (Allo-HSCT) in Children with high-risk Acute Leukemia (AL)

Anastasia Frolova, Olesia Paina, Alisa Volkova, Polina Kozhokar, Zhemal Rakhanova, Lubov Tsvetkova, Kirill Ekushov, Inna Markova, Elena Babenko, Aleksandr Alyanskiy, Ildar Barkhatov, Maria Vladovskaya, Elena Semenova, Ludmila Zubarovskaya, Boris Afanasyev

Pavlov First Saint Petersburg State Medical University, Saint-Petersburg, Russian Federation

Background: Despite advanced effective prophylaxes, PC occur in 40-60% of allo-HSCT recipients, accounting for considerable morbidity and mortality. Transplant procedure influence on development of PC, eg conditioning regimen, immunosuppresive therapy, status of diseases, but complex of these aspects didn’t analyzed in children underwent allo-HSCT. Primary end point:to determine effect of PC in children with AL after allo-HSCT on overall survival (OS). Secondary end points:to describe causes, incidences rates PC and risk factors of such complications following allo-HSCT.

Methods: We included children (n=173) with ALL (n=99) and AML (n=74), median age 11(0-18)y.o. Remission of disease (CR) at allo-HCST was in 108 pts (62%). Related compatible donor-in 16(9%) patients, 80(46%) haploidentical, and 77(45%) matched unrelated donor. Source of HSC was bone marrow (BM) n=138, peripheral blood stem cells (PBSC) n=35 cases. Myeloablative conditioning regimen (MAC) based on busulfan (Bu) (10-16 mg/b.w.) received 105(92%) patients on treosulfan-9(8%) pts., reduced intensity conditioning (RIC) based on melphalan-37(63%) pts, based on Bu(8 mg/b.w.)-22(37%) pts. GVHD prophylaxis was mono-PTCy in 25pts (15%), PTCy±CNI±m-TOR in 68 pts(39%), PTCy±CNI±MMF in 80 pts(46%). Clinical data were analyzed to determine whether the incidence of PC was correlated with risk factors such as age, sex, underlying disease type, transplant type, conditioning regimen, prophylaxis of GVHD using SPSS 23. Kaplan-Meier curves were used to estimate the probability of OS. A p value of < 0.05 was considered statistically significant.

Results: Among 173 pts 121(69%) had PC. Early pulmonary complications (EPC) (before D+100) occurred in 81% (n=98) of pts. Infections EPC observed in 97%(n=95): bacterial complications in 23pts(24%), fungi in 13pts(14%), viruses in 15pts (16%), combined infections: viruses+bacteria in 19pts (20%), viruses+fungi in 7(7%), bacteria+fungi in 11(11%), and combination of viruses, bacteria and fungi in 7(7%) cases. Non-infectious EPC occurred in 39%(n=38)pts: engraftment syndrome 40%(n=15), pulmonary edema 39%(n=15), pulmonary bleeding 3%(n=1), respiratory distress syndrome 13%(n=5). Late pulmonary complications (LPC) (after D+100) occurred in 66%(n=80) pts., infectious LPC observed in 30% (n=24), non-infectious LPC observed in 26%(n=21)pts. According to our data pulmonary changes were seen in 80 pts. In 24(30%) cases were focal, in 17(21%) infiltrative, in 26(33%) interstitial, and 10(13%) cases fibrotic. Three pts developed hydrothorax. 41 pts had no complications. Development of EPC in underlying diseases significantly affects overall survival (p=0.001). 5-OS in patients with early mild complications is 55%vs92.1% without complications. The OS of pts with LPC is 72,7% compared 61.5% of patients who had EPC and LPC (p=0.001). Incidence of PC in remission after МАС is 67,5%(n=77)vs72,9% (n=43) after RIC(p>0,05). Incidence of PC in pts with active underlying disease after MAC-70%(n=31) vs 95%(n=20) after RIC. Type of allo-HSCT, source of transplant, sex, age at the moment of allo-HSCT in CR pts didn’t affect on development of PC(p>0,05).

Conclusions: Incidence of PC was significantly lower in patients receiving allo-HSCT in CR. Intensity of conditioning regimen does not affect the incidence of PC in patients with CR. The use of RICs in relapse increases incidence of PC. Development of early PC in patients after allo-HSCT worsens the prognosis and reduces significantly OS.

Disclosure: Nothing to declare.

P017 More than two Cycles of Consolidation Therapy pre-transplantation Benefits AML Patients in Cr1 Who Underwent HLA-matched Sibling Allografts: A Multicenter Study

Jing Liu1, De-Pei Wu2, Qi-Fa Liu3, Yang Xu4, Fen Huang3, Xiao-Jun Huang1, Yu Wang4

1Peking University People’s Hospital & Peking University, Beijing, China, 2Affiliated Hospital of Soochow University, Soochow, China, 3Nanfang Hospital, Southern Medical University, Guangzhou, China, 4First Affiliated Hospital of Soochow University, Soochow, China

Background: Although the need for consolidation chemotherapy after successful remission induction therapy is well established in patients acute myeloid leukemia (AML) in first complete remission (CR1), the value of consolidation chemotherapy before HSCT remains controversial.

Methods: Our study retrospectively compared the effect of the number of pre-transplant consolidation on outcome after HLA-matched sibling stem cell transplantation (MSDT) for AML patients in CR1 in multicenters across China. In addition, our multicenter study also compared the effect of the consolidation therapy pre-transplant between MRD negative patients and MRD positive patients with AML in CR1 who received MSDT.

Results: In our study, we analyzed data of 373 patients with AML in CR1 from three centers across China. All of these 373 patients received MSDT in different centers. With a median follow-up of 969 days, those patients with ≧ 3 cycles of consolidation chemotherapy had higher incidences of LFS (85.6% vs. 67.0%, p< 0.001) and OS (89.2% vs. 78.5%, p=0.007), and better cumulative incidences of relapse rate (10.5% vs. 19.6%, p=0.020) and NRM (4.2% vs. 14.9%, p=0.001). For pre-MRD (minimal residual disease) negative AML patients in CR1 receiving MSDT with ≧ 3 cycles of consolidation chemotherapy had better LFS (85.9% vs. 67.7%, p=0.003) and lower cumulative probabilities of relapse (9.6% vs. 23.3%, p=0.013) than those with ≦ 2 cycles, but the two groups had comparable probabilities of OS (90.0% vs. 80.3%, p=0.051) and NRM (4.9% vs. 10.9%, p=0.127).

Conclusions: In conclusion, our results indicated that AML patients in CR1 who received MSDT might benefit from pre-transplant consolidation chemotherapy.

Disclosure: All authors declare. no competing financial interests.

P018 What can Cnv Analysis add to the Routine Genetic Description of AML Cases?

Emilia Jaskula1,2, Mariola Sedzimirska2, Monika Mordak-Domagala2, Janusz Lange2, Krzysztof Suchnicki2, Anna Sobczynska-Konefal2, Marta Lemieszewska2, Helena Pakos2, Agnieszka Tarnowska2, Andrzej Lange1,2

1Polish Academy of Sciences, Wroclaw, Poland, 2Lower Silesian Center for Cellular Transplantation with National Bone Marrow Donor Registry, Wroclaw, Poland

Background: Genetical description of AML cases belong now to the standard diagnostic procedure, however it includes mainly chromosome banding assay (CBA) or FISH. In the present study we added information from microarray CNV analysis.

Methods: 127 AML cases (age:21-84, median:59 yrs, 62F/65M) diagnosed in years 2008-2019 (FAB M0=11, M1=37, M2=25, M3=6, M4=27, M5=11, M6=2, secondary=20, primary=107), classified (ELN genetic guidelines) as favourable=17.3%, intermediate=51.2%, unfavourable=31.5%, received treatment according to the PALG guidelines. Genetic work in addition to the CBA, 83 cases or FISH analysis (33 cases) included the microarray analysis of copy number variations (CNV).

Results: 1. The observed survival pattern of the patients followed that seen in the ELN analysis on the dependence of CBA and FISH alterations with survival.

2. CNV number (Catalog Agilent Cancer CGH+SNP 180K (74 patients) or Roche-WG Catalog NimbleGene 12x270K (53 patients)) was worked out using the Partek program (segmentation algorithm with default settings). Numbers of CNVs deletions in the patients varied from 3-104 (median: 22), amplifications from 6-172 (median: 26). Only autosomes were analysed.

3. 197 CNVs> 5 Mbp found in 38 patients could be compared to the picture of CBA in 14 and that of FISH in 24 patients. It appeared that CNV detected were seen either in the CBA or in the FISH in 86 situations. 111 identified CNVs were missed in CBA or FISH among which in 73 instances because the FISH probes are not suited for detection of these particular CNV, the rest 38 CNV which might be seen either in CBA or FISH were missed likely due to the technical reasons. A majority of discrepant results between the FISH or CBA and microarray were likely due to difficulties in proper identification of a part of additional or deleted chromosome seen (6 patients). Altogether, the results of CNV and the standard techniques were the same in 25 cases.

4. In a univariate analysis of the survival risk factors, it was found that better overall survival enjoyed patients:

· under 48 years of age (39 vs 16%, p< 0.001),

· with primary AML (23% vs 15%, p=0.084) compared to secondary AML,

· lacking NPM1 gene mutation (25 vs 11%, p= 0.044),

· who received allogeneic hematopoietic stem cell transplantation (28 vs 19%, p< 0.001),

· having more CNV aberrations in the group with normal karyotype or FISH (50 vs 16%, p=0.008),

· having t(8:21) (RUNX1/RUNXT1, 67 vs 20%, p=0.004). 67% of patients with t(8:21) had an aberrant expression of CD19 (>22% in the blasts) compared to 5% incidence in the patients without translocation (p< 0.001). CNV amplification in the RUNX1 gene was associated with aberrant CD19 expression (40% vs 7%, p= 0.054). In opposite CNV amplifications in the KMT2A gene (9 cases), independently if seen in the FISH assay (3 cases) or not, inversely affected the survival (0 vs 43%, p= 0.032, at the 18 month time point).

Conclusions: CNV analysis offers some information which are clinically valid but missed by CBA or FISH due to the technical reasons.

Supported by RPDS.01.02.01-02-0177/17 “Stawreg” grant.

Clinical Trial Registry: no applicable

Disclosure: The authors declare. that they have no conflict ofinterest.

P019 Comparison of the Prognostic Ability of the HCT-CI the Modified EBMT and the EBMT-ADT Pre-transplant Risk Scores for Acute Leukemia

Eshrak Al-Shaibani1,2, Sunu Cyriac1,2, Shiyi Chen1,2, Jeffrey H. Lipton1,2, Dennis D. Kim1,2, Auro Viswabandya1,2, Rajat Kumar1,2, Wilson Lam1,2, Arjun Law1,2, Zeyad Al-Shaibani1,2, Armin Gerbitz1,2, Ivan Pasic1,2, Jonas Mattsson1,2, Fotios V. Michelis1,2

1Princess Margaret Cancer Centre, Toronto, Canada, 2University of Toronto, Toronto, Canada

Background: Allogeneic hematopoietic cell transplantation (HCT) may provide cure for acute leukemia where indicated. However, its use is limited by transplant-related complications which lead to increased mortality. This has prompted the development of pre-transplant risk scores such as the Hematopoietic Cell Transplantation-Comorbidity Index (HCT-CI) and the modified European Group for Blood and Marrow Transplantation (mEBMT) score (that examines recipient age, remission status of leukemia, donor-recipient gender combination and donor match). In a large EBMT study Shouval et al (Journal of Clinical Oncology, 2015) developed a machine learning-based prediction model for mortality (EBMT-ADT) that can be used online.

Methods: In the present retrospective study, we examined the impact of the HCT-CI, mEBMT and EBMT-ADT on a single center cohort of 231 patients who underwent allogeneic HCT for acute leukemia from August 2014 until December 2017. Data was updated as of October 2019.

Results: Median age was 56 years (range 19-72). Acute myeloid leukemia (AML) was diagnosed in 200 patients, acute lymphoblastic leukemia (ALL) in 31 patients. Disease status at the time of HCT was first complete remission (CR1) in 81% and CR2 or beyond in 19% of patients. Myeloablative conditioning was administered to 31% of patients while 69% received reduced intensity conditioning. In vivo T-cell depletion was given to 76% of patients. Donors were HLA matched related in 33%, 10/10 matched unrelated in 44%, 9/10 unrelated in 12% and haploidentical in 11% of patients. The median follow up of survivors was 37 months (15-62 months).

For the HCT-CI, patients were grouped as score 0-1, 2-3 and >3 (116, 75 and 40 patients respectively). For the mEBMT score, patients were grouped as 0-2, 3 and 4-5 (76, 121 and 34 patients respectively), while for the EBMT-ADT the respective 100-day mortality was calculated for each patient (excluding haploidentical) and grouped as ≤4.1%, 4.1-11.5% and >11.5%. Patients with higher HCI-CI score demonstrated lower probability for OS (p=0.038, c-statistic 0.57), while neither mEBMT nor EBMT-ADT significantly stratified patients into prognostic groups (p= 0.09, c-statistic 0.54 and p=0.28, c-statistic 0.53 respectively). Multivariable analysis for OS demonstrated that leukemia type (HR 1.82 for ALL, 95% CI 1.16-2.85, p=0.01), HLA matching (HR 0.61 for all fully matched donors, 95% CI 0.41-0.90, p=0.01) and HCT-CI (HR 0.50 for 0-1, 95% CI 0.31-0.81, p=0.004) had significant impact. Based on the HR, a new weighted score was developed for this cohort including leukemia type (AML=0, ALL=1), HLA matching (fully matched=0, mismatch unrelated or haploidentical=1) and HCT-CI (0-1=0, 2-3=1 and ≥4=2). The new score demonstrated improved prognostic capability compared to the other scores (p=0.0004, c-statistic 0.60) (Figure 1).

Conclusions: The mEBMT score and the EBMT-ADT do not adequately prognosticate OS in our cohort of acute leukemia patients undergoing allogeneic HCT. The HCT-CI performs better, however is not a powerful predictor. New approaches are required to develop a pre-transplant risk calculation tool that can be widely applicable to patients from various centers characterized by heterogeneous practices.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (4)

[Figure 1: stratification of OS by score based on leukemia subtype, mismatch and HCT-CI”]

Disclosure: Nothing to declare.

P020 GO-FLAG Regimen as a Bridge Therapy to Allogeneic Stem Cell Transplantation in Refractory/relapsed AML Patients

Bella Ayubova1, Sergey Bondarenko1, Ivan Moiseev1, Olga Uspenskaya2, Elena Karyagina3, Elena Misyurina4, Evgenia Zhelnova4, Alexander Alyanskiy1, Elena Babenko1, Ildar Barkhatov1, Tatyana Gindina1, Alexander Kulagin1, Boris Afanasyev1

1Pavlov First State Medical University of St. Petersburg, St. Petersburg, Russian Federation, 2Leningrad Regional Clinical Hospital, St. Petersburg, Russian Federation, 3City Hospital No.15, St. Petersburg, Russian Federation, 4City Clinical Hospital No.52, Moscow, Russian Federation

Background: The patients (pts) with refractory or relapsed AML (r/rAML) have poor outcomes with 3-year overall survival (OS) no more than 10%. The main goal of therapy in pts with r/rAML is to achieve remission followed by allogeneic hematopoietic stem cell transplantation (alloHSCT). Introduction of targeted drugs is the most promising strategy in the modern therapy of hematological malignancies. Gemtuzumab ozogamicin (GO) is a recombinant, humanized anti-CD33 monoclonal antibody covalently attached to the cytotoxic antitumor antibiotic calicheamicin, which effectiveness depends on more than 75% expression of CD33-glycoprotein on leukemic blasts.

Methods: The study included 39 pts with median age 34 (18-61) years, 12/39, 31% pts were with primary refractory AML (RefAML), 27/39, 69% pts were with relapsed AML (RelAML). The first relapse (Rel1) had 19/27, 70% pts and two or more relapses (Rel>2) - 8/27, 30%. The early relapse (eRel) was observed in 23/27, 85% and late relapse (lRel) were in 4/27, 15% of cases. Based on the ELN 2017 classification, the prognosis was favorable for 10 pts (26%), intermediate for 8 pts (20%), and adverse for 21 pts (54%). All pts treated by the combination of fractionated GO with regiment FLAG (GO-FLAG).

Results: The follow-up period was 27 month. The overall response rate (OR) was 69% (95% CI 54-81): complete remission was achieved in 63%, remission with incomplete hematologic recovery - 37%. The high OR was in pts with extramedullary disease - 85% (95% CI 58-96). AlloHSCT was performed after GO-FLAG in 17 (44%) pts (4- related, 4 - unrelated, 9 - haplo). In two cases alloHSCT was done in active disease. The median time from OR after GO-FLAG to HSCT was 61 (36-148) days. Overall survival and disease-free survival at 1 years (OS1 and DFS1) was 64% (95% CI 48-77) and 63% (95% CI 44-78), respectively. In the allogeneic group the median OS1 was 6 months and in the group without alloHSCT - 2 months. The median DFS1 in pts with and without alloHSCT after GO-FLAG was 4 and 3 months, respectively. The predictive factors associated with a higher response rate were: favorable ELN genetic group (favorable-90% vs intermediate-75% vs adverse-57%, p=0,05); RelAML (RefAML-42% vs RelAML-81%, р=0,02); blast level less than 60% (< 60% level -83% vs >60% level -50%, р=0,03). In all cases we observed neutropenia of 4 gr. and thrombocytopenia 4 gr. Severe hemorrhagic complications (subdural hematoma) was in 1 pts (2,6%). Sepsis was in 13% (95% CI 19-46); fungal infections were in 10% (95% CI 4-24). Hepatotoxicity was presented as a transient increase in ALT level (< 10ULN) in 10% (95% CI 4-24). Sinusoidal obstruction syndrome did not occur in any of the patients. Early mortality was 10% (95% CI 4-24), 4/39 pts. Causes of death were leukemia progression (1 pt), infectious complications (3 pts). No direct association with the GO and death was observed.

Conclusions: GO-FLAG demonstrated the efficacy and acceptable toxicity in pts with r/rAML and can be used as a bridge to alloHSCT.

Disclosure: Nothing to declare.

P021 The Impact of Allogeneic Transplantation in AML and Mds with Chromosome 3 Abnormalities

Maria Rhida Bautista1, Shiyi Chen2, Wilson Lam1, Fotios Michelis1, Dennis Kim1, Jeffrey Lipton1, Auro Viswabandya1, Rajat Kumar1, Ivan Pasic1, Armin Gerbitz1, Jonas Mattson1, Zeyad Al-Shaibani1, Arjun Law1

1University of Toronto, Toronto, Canada, 2Princess Margaret Cancer Center, Toronto, Canada

Background: Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome (MDS) with chromosome 3 abnormalities are associated with adverse outcomes. The benefit of allogeneic stem cell transplantation (AlloHCT) in this setting is controversial. This study aims to assess outcomes in this group of patients undergoing AlloHCT.

Methods: This is a single-center retrospective study including 52 patients with AML and MDS with chromosome 3 abnormalities by conventional karyotyping, who received Allo-HCT from October 2000 to August 2019.

Results: The median age of patients was 50 years old (range 19-72). There were 38 patients with AML and 14 patients with MDS. Concurrent presence of monosomy 7 and complex cytogenetics was found in 15 (29%) and 36 (69%) patients respectively. Majority of patients with AML were in first complete remission (CR1) at the time of AlloHCT. Patients with MDS were Intermediate-2 (13%) or High risk (12%) by the International Prognostic Score System (IPSS). Patient and transplant characteristics are summarized in Table 1.

With a median follow up of 4 years, 2-year relapse free survival (RFS) was 33.65% (95% CI, 20.75-47.03), overall survival (OS) was 32.46% (95% CI, 19.63-45.95), cumulative incidence of relapse (CIR) was 48.08% (95% CI, 35.39-65.31), non-relapse mortality (NRM) was 17.57% (95% CI, 10.18-30.33) and graft vs host disease relapse free survival (GFRS) was 22.94% (95% CI 12.17-35.75). Compared to other chromosome 3 abnormalities, patients with monosomy 3 showed the highest risk of relapse and death with 2 year RFS 11.53% (95% CI, 0.86% - 37.51%) and OS 10.26% (95% CI, 0.67% - 35.53%).

On univariate analysis, age greater than 50, monosomy 3, the presence of monosomy 7 and Allo-HCT in AML in CR2 or not in remission, were associated with increased risk of relapse and death. On multivariate analysis, AML in CR1 showed a trend towards improved RFS and OS, however, this was not statistically significant (HR 0.45 (0.20 - 1.04), P= 0.06 and HR 0.45 (0.20 - 1.02), P=0.056 respectively). The presence of monosomy 7 also showed a trend towards increased risk of relapse, however, this was also not statistically significant (HR 2.13 (0.96 - 4.7), p=0.06) (Table 2).

Conclusions: AlloHCT may improve outcomes in select patients with AML/MDS with chromosome 3 abnormalities. Further studies with a larger sample size and the inclusion of molecular mutations are recommended.

Disclosure: Nothing to declare.

P022 Allogeneic Hematopoietic Stem Cell Transplantation Versus chemotherapy-alone in the Treatment of Pediatric Acute Myeloid Leukemia Patients with Mixed Lineage Leukemia (Mll) Rearrangements: Single Center Experience

Ibtisam AlQahtani, Amal Al-Seraihy, Ali Alahmari, Mouhab Ayas, Khawar Siddiqui, Ibrahim Ghemlas

King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia

Background: Acute myeloid leukemia (AML) represents 15%-20% of childhood leukemia. Despite substantial progress in the treatment of pediatric AML, approximately 40% of patients die from disease recurrence or treatment-related toxicities. Cytogenetic aberrations and response to the treatment are important prognostic factors in AML. MLL gene rearrangements in AML patients result in unique clinical and molecular genetic characteristics and generally indicate a poorer prognosis. At King Faisal Specialist Hospital and Research Centre (KFSH&RC), Riyadh, we examined the incidence and treatment outcome of MLL-rearranged AML pediatric patients.

Methods: We retrospectively reviewed the clinical data of pediatric patients (age at presentation ≤ 14 years) who were diagnosed and managed at KFSH&RC from January 2005 to December 2016. A total of 201 de novo AML patients´ profiles were reviewed, MLL-rearranged AML patients were identified based on the cytogenetic results. The median follow-up was 104±37.4 Months (95% CI: 30.5-177.6) Months.

Results: A total of 21 out of 201 (10.4%) AML patients found to have MLL gene rearrangements, 52%(11) were female, with a median age at diagnosis of 3.83 years (0.54-13.56). French-American-British (FAB) classification was M5 in17 patients(81%), M4 in 2(9.5%), M7 in 1(4.8%), and M1 in 1(4.8%). The commonest identified partner was t(9,11) in 8 patients(44.4%), followed by t(1,11) and t(11,19) in 4 patients (22.2%) each, t(11,18) and t(6,11) in 1 patient (5.6%) each. Three patients died early within 1 month from diagnosis. 14 out of 18 (77.8%) patients achieved complete remission 1 (CR1) after AML induction chemotherapy with cytarabine/daunorubicin/etoposide (ADE 10+3+5) and cytarabine/daunorubicin/etoposide (ADE 8+3+5).

Three out of 18 (16.6%) required second-line chemotherapy to achieve CR1. One patient failed to achieve CR despite second-line chemotherapy.

The 5-year Overall Survival (OS) for all MLL-rearranged AML patients was 42.9±10.8%. A total of 10 patients treated with chemotherapy alone without hematopoietic cell transplantation HSCT in complete CR1, 5 out of 10 patients have died with progressive disease (PD) /early relapse within an average of 6 months (1-9 months) from CR. 8 patients underwent HSCT in CR1, 4 died with relapse within an average of 13 months (6-18 months), 3 of them failed induction and got second-line chemotherapy before HSCT. All relapsed patients failed to achieve CR2 and died with PD.

Conclusions: Incidence of MLL gene rearrangements in our Centre was 10.4% and associated with poor outcomes. MLL-rearranged AML patients associated with increased risk of early relapse and re-induction failure. CR1 after first-line chemotherapy is an independent prognostic factor.

Disclosure: nothing to declare.

P023 Posttransplantation Bendamustine for GVHD Prophylaxis in Refractory Acute Leukemia Patients

Ivan Moiseev, Sergey Bondarenko, Elena Darskaya, Alexandr Alyanskyi, Anastasiya Beynarovich, Evgeniya Borzenkova, Anna Dotcenko, Olga Kudyasheva, Varvara Ovechkina, Olga Pirogova, Valentina Porunova, Tatyana Rudakova, Olesya Smikova, Boris Afanasyev

Pavlov First Saint Petersburg State Medical University, Saint-Petersburg, Russian Federation

Background: Results of allogeneic stem cell transplantation (SCT) in primary or secondary refractory leukemia patients remain unfavorable despite the studies of new conditioning regimens. Preclinical studies by Stokes et al. (2016) indicate that substitution of posttransplantation cyclophosphamide with bendamustine (PTbenda) can possibly augment graft-versus-leukemia (GVL) effect in active leukemia mouse model. We conducted a study to evaluate the potential of PTbenda to prevent graft-versus-host disease (GVHD) and potentiate GVL.

Methods: The prospective (NCT02799147) Phase I de-escalation study evaluated 140-100-70 mg/m2 of PTbenda administered on days +3,+4 with or without additional immunosuppressive agents. All patients received myeloablative conditioning with fludarabine and busulfan. Inclusion criteria were diagnosis of acute lymphoblastic (ALL) or acute myeloblastic leukemia (AML), failure of at least to previous induction courses of chemotherapy or immunotherapy, more than 5% of clonal blasts in the bone marrow and good somatic status. The study enrolled 26 patients (pts), enrollment to the 140 mg/m2 group was halted due to stopping rules. Five pts had ALL and 21 - AML. Median blast count was 19% (6-97%). Four pts had matched sibling donor, 15 - matched unrelated donor and 7 - haploidentical, 10 pts had primary refractory and 16 secondary refractory disease. Half of patients received systemic antimicrobial therapy at the time of enrollment. Median age was 27 years (20-56).

Results: All patients but two with ALL disease progression engrafted and 89% had complete remission (CR) after engraftment, while 62% were MRD-negative. The evidence of augmented GVL was supported by the presence of cytokine-release syndrome in 73% of patients: 3 pts had grade 5 CRC, 5 pts - grade 4, 7 - patients grade 3 and 4 pts - grade 1-2. The pattern of CRC was distinct from BiTe and CAR-T one, with fever in all patients, skin vasculitis in 50%, liver function test elevation in 50%, polyserositis in 15% and neurotoxicity in 15%. CRC was associated with significant elevation of serum ferritin (mean 20188 vs 4915 ng/ml, p=0.005). 1-year overall survival was 29%, 40% and 70% in 140, 100 and 70 mg/m2 groups, respectively, but event-free-survival was 29%, 40% and 27% (Figure 1). None of ALL patients had long-lasting CR (0% vs 45%, р< 0.001). In the whole group relapse incidence was 19% and non-relapse mortality (NRM) - 43%. Grade III-IV acute GVHD was observed in 43%, 30% and 33% pts, with significantly higher incidence after haploidentical transplantation (75% vs 22%, p=0.046). Seventy percent of long-term survivors had chronic GVHD with higher incidence after single-agent PTbenda (100% vs 40%, р=0.038).

Conclusions: PTbenda is a promising strategy for refractory AML, but elucidation of the optimal immunosuppressive agent combination is required to control GVHD, CRC and reduce NRM.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (5)

[Figure 1. Event-free survival]

Clinical Trial Registry: NCT02799147, clinicaltrials.gov

Disclosure: The authors declare. no conflicts of interest.

P024 Immediate Allogeneic Hematopoietic Stem Cell Transplantation for NPM1-mutated AML in Molecular Relapse

Kerstin Schaefer-Eckart1, Knut Wendelin1, Sabine Dressler1, Johannes Gaertner1, Christian Thiede2

1Paracelsus Medizinische Privatuniversität, Nürnberg, Germany, 2Universitätsklinikum Dresden, Dresden, Germany

Background: NPM1-mutations can be identified in about 30% of adult AML patients (pts). According to ELN 2017 classification they are characterized as favorable or intermediate risk depending on the coexistence of FLT3 mutations. For pts with a favorable risk profile an allogeneic hematopoietic stem cell transplantation (HSCT) in first complete remission (CR) is not recommended, but can be an option for the intermediate risk group, depending on risk factors like comorbidity. Approximately 30% of NPM1-mutated AML pts will relapse after chemotherapy. Because NPM1 mutations are stable, and persisting or increasing levels are a strong predictor of relapse, monitoring of minimal residual disease (MRD) by quantitative PCR (qPCR) is recommended. With this strategy relapse can be detected earlier with lower leukemia burden. HSCT in molecular relapse could avoid possible complications of reinduction chemotherapy, but there are no data for this strategy. In 2014 we decided to start donor search immediately after molecular relapse and proceed to HSCT without reinduction chemotherapy. Here we report our experience with the first 6 pts treated with this strategy.

Methods: Between January 2014 and December 2018 28 patients under the age of 70 years, who were fit for intensive chemotherapy were diagnosed with NPM1-mutated AML. All pts received induction with DA 3+7 followed by consolidation with high-dose AraC in 15 pts. In 10 pts HSCT as consolidation treatment was performed. 3 pts had induction failure. MRD was monitored at least every 3 months (mos) after end of consolidation therapy by qPCR in bone marrow or peripheral blood in all pts in hematological CR. Relapse was defined as an increase of MRD over a cut-off of 1% NPM1/ABL1. The conditioning regimen consisted of Treosulfan (Treo, 30g/m2) and Fludarabin (Flu, 120mg/m2). In pts with hematological relapse at the time of HSCT Melphalan (Mel, 100mg/m2) before Treo/Flu was added to induce aplasia. Immunosuppression consisted of ATG and Ciclosporin in combination with MTX or MMF.

Results: 25/28 pts achieved hematological CR after induction therapy, 24/25 pts showed molecular CR after the end of consolidation treatment. 10 pts (40%) relapsed. 4/10 pts developed an overt hematological relapse and are not part of this analysis. In 6 pts molecular relapse was detected. 5/6 pts relapsed after complete molecular remission, 1 pt relapsed after MRD positive remission. The median time to molecular relapse was 8 (7-42) mos after diagnosis. Median time from first positive MRD to HSCT was 2 (2-4) mo. 3/6 pts received conditioning with Treo/Flu only. 3/6 pts had hematological relapse at time of HSCT and received Treo/Flu after induction of aplasia with Mel. All pts reached complete hematological and molecular remission after HSCT. After a median follow-up of 15 (8-47) mos all pts are in ongoing CR. In all but one pt the remission free survival is longer than after primary treatment.

Conclusions: Although the number of pts is small and the follow-up short, this analysis shows the efficacy and feasibility of early allogeneic HSCT in molecular relapse for NPM positive AML pts and should be confirmed in a greater number of pts.

Disclosure: No disclosure

P025 Flat Regimen as Myeloablative Conditioning with Limited Toxicities for Autologous Stem Cell Transplantation in Patients with Acute Myeloid Leukemia: Results in 30 Patients

Massimo Bernardi, Carlo Messina, Sara Mastaglio, Francesca Lorentino, Francesca Pavesi, Matteo Giovanni Carrabba, Jacopo Peccatori, Andrea Assanelli, Luca Vago, Bernhard Gentner, Raffaella Milani, Paola Ronchi, Fabio Giglio, Carmine Liberatore, Federico Erbella, Daniela Clerici, Fabio Ciceri

IRCCS San Raffaele Scientific Institute, Milan, Italy

Background: consolidation of complete remission (CR) with autologous stem cell transplantation (ASCT) is an option for patients (pts) with acute myeloid leukemia (AML), in particular for those with a favourable genetic risk (ELN 2017). Most conditioning regimens for ASCT contain at least one alkylating agent, usually busulfan, cyclophosphamide or melphalan. Up to now, no regimen has proved preferable in terms of toxicities and improvement of event free survival (EFS). Treosulfan is an alkylating agent which demonstrated to achieve maximum disease control with minimal toxicity in combination with fludarabine prior to allogeneic SCT. We designed and tested a new treosulfan-based conditioning regimen (FLAT) prior to ASCT in AML pts in first complete remissione (CR1). Preliminary data on the feasibility and efficacy of the FLAT regimen are here presented.

Methods: period 7/2006-7/2019, 30 pts with AML in CR1, median age 68 y (18-76), 14 pts £ 65 y (group A: median 49 y, 19-65), 16 pts > 65 y (group B: median 73 y, 68-77). Cytogenetics: favourable 1, intermediate 26 (normal karytotype 25), complex 1, not evaluable 2. Molecular (21 pts): CBFB-MYH11 1, RUNX1-RUNX1T1 1, NPM1mut alone 5, CEBPAmut alone 4, FLT3ITD/NPM1mut 5 (FLT3ITD low ratio 3, unknown ratio 2), negative 5. Prognostic risk (ELN 2017): favourable 14, intermediate 7, adverse 1, not evaluable 8. At ASCT all pts were in CR1 after a median number of 2 chemo cycles (2-4). FLAT regimen: treosulfan 10 gr/sqm for 3 days, fludarabine 30 mg/sqm for 5 days, cytarabine 2 gr/sqm for 5 days, PEG filgrastim 1 vial s.c. after autoSCT (27 pts). Graft: PBSC, median CD34+ 5x106/kg of BW (3.3-8.5). Time from CR1 to autoSCT: median 99 days (44-266).

Results: at day +100 after ASCT 29 pts were alive, 24 in CR, 5 relapsed. One 75-yo patient died for invasive fungal infection at day +31 (she was still in G4 pancytopenia). Median time to hematopoietic recovery: neutrophils (> 500/mcl) day +11 (8-38), platelets (> 20.000/mcl) day +20 (13-103). Neutrophils recovery in 3 pts who did not receive any growth factor was slower (day +26, 33, 38). Extra-hematologic toxicities (CTCAE v4.0): median grade 1 (0-4). Median EFS from ASCT was 1123 days (31-4808), for group A 1123 days (84-4808), for group B 653 days (31-4789); projected 3y EFS from ASCT was 51.2%, for group A 57.1%, and group B 47.8% (p=ns). At last update 15 pts (50%) are alive, 13 in CR1, 2 in second CR, with a median follow up of 1561 days (146-4810). Overall non-relapse mortality was 3%.

Conclusions: consolidation of AML in CR1 with the new myeloablative FLAT regimen and ASCT was feasibile and well tolerated, even in patients above 65 years of age. Around 50% of pts, regardless of age, mostly with favourable or intermediate genetic risk, obtained prolonged survival without relapse.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (6)

[EFS from ASCT]

Disclosure: nothihg to declare.

P026 Tyrosine Kinase Inhibitor Treatment after Allogeneic Hematopoietic Stem Cell Transplantation for Philadelphia Chromosome‐positive Acute Lymphoblastic Leukemia

Yu-Hsiang Chang1,2, Xiu-Wen Liao1, Jia-Hau Liu1,2, Ming Yao2, Bor-Sheng Ko2, Chi-Cheng Li3, Cheng-Hong Tsai2, Shang-Ju Wu2, Hui-Hsuan Huang2, Tai-Chung Huang2, Hsin-An Hou2, Wen-Chien Chou2, Feng-Ming Tien1,2, Yun-Chu Lin2, Meng-Yao Lu2, Kai-Hsin Lin2, Jih-Luh Tang1,4

1National Taiwan University, Taipei City, Taiwan, Republic of China, 2National Taiwan University Hospital, Taipei City, Taiwan, Republic of China, 3Hualien Tzu Chi Hospital, Hualien City, Taiwan, Republic of China, 4National Taiwan University Cancer Center, Taipei City, Taiwan, Republic of China

Background: Introduction of tyrosine kinase inhibitor (TKI) for the treatment of Philadelphia chromosome‐positive acute lymphoblastic leukemia (Ph+ ALL) has dramatically improved the survival outcomes. However, TKI therapy for Ph+ ALL has yielded controversial results evaluating the efficacy of post-hematopoietic stem cell transplantation (HSCT). The CIBMTR analyzed 197 patients with Ph+ ALL undergoing allo-HCT in first complete remission, 43 of whom received post-transplant therapy with TKIs. There was no difference in the 3-year cumulative incidence of relapse. In contrast, an EBMT study of 473 patients showed that post-transplant TKI was associated with a lower relapse rate and better overall survival. Recently, Akahoshi et al reported that TKI prophylaxis was not associated with a decreased risk of relapse or superior overall survival in the whole cohort. Therefore, we conducted a retrospective study of Ph+ ALL patients at our hospital to evaluate whether TKI prophylaxis after allogenic HSCT would reduce relapse and improve overall survival.

Methods: The Institutional Research Board approved the retrospective study. We identified 68 patients over 14 years of age with Ph+ ALL who received allo-HSCT from 1993 to 2001 (n=3) and from 2002 to 2019 (n=65) at National Taiwan University Hospital. Univariate and multivariate analysis was performed using Cox proportional hazard regression model.

Results: Before allo-HSCT, 8 of 68 patients (12%) didn’t receive any TKI treatments, whereas the remaining 60 patients received imatinib (24%), dasatinib (54%), nilotinib (6%), and ponatinib (4%). After allo-HSCT, 28 patients (41%) didn’t receive TKI treatments, and 40 patients (59%) received TKI treatment, including 2 patients (3%) with flank relapse, 17 patients (25%) with TKI prophylaxis and 21 patients (31%) with pre-emptive treatment because of positive-minimal residual disease (MRD) detected by quantitative PCR. The median time from HSCT to TKI treatment was 52 days (range, 21-542 days). Imatinib (15%), dasatinib (38%), nilotinib (4%), and ponatinib (2%) were given as TKI treatment. The median duration of TKI treatment of the patients was 453 days (range, 7-1775 days). Multivariate analysis identified advanced disease status before HSCT (primary induction failure, active disease) to be a risk factor for overall survival (OS) (HR=7.156; P=0.0002), disease-free survival (DFS) (HR=4.829; P=0.0113), and cumulative incidence of relapse (CIR) (HR=5.3; P=0.0188). Importantly, in the post-transplant period, the multivariate analysis identified TKI administration to be a significant factor for OS (HR=0.30; P=0.0014), DFS (HR=0.25; P<0.001), and CIR (HR=0.343; P=0.0039). Molecular relapse detected by quantitative PCR after HSCT was correlated with increased risk of hematological relapse (CIR, HR=8.158; P=0.005), but not associated with a worse DFS (HR=1.042; P=0.8827). This result could be explained by the fact that 21 of the 32 patients with molecular relapse received TKI treatment and 9 of them returned to negative MRD in a later follow-up assessment.

Conclusions: Despite the limitation of small sample size and the potential bias of patient selection by the physician, our study showed TKI treatment after allogeneic HSCT would reduce relapse and improve overall survival, indicating the potential benefit of TKI treatment in the post-transplant setting.

Disclosure: Nothing to declare.

P027 Outcomes of Allogeneic Transplantation for Cytogenetic intermediate-risk AML According to the Molecular Risk Based on ELN 2017 Risk Stratification System; Single Center Experience in Korea

Haerim Chung, Ji Eun Jang, SooJeong Kim, Jin Seok Kim, Yoo Hong Min, June-Won Cheong

Yonsei University, Seoul, Korea, Republic of

Background: Acute myeloid leukemia (AML) has been recognized as a clinically and genetically heterogeneous disease entity. Cytogenetic abnormalities that are associated with the prognosis of AML have been identified. However, as there are limitations for patients in the cytogenetic intermediate-risk group, more precise risk stratification systems based on genetic status have been proposed especially in nest-generation sequencing (NGS) era. In this study, we evaluated the usefulness of the European Leukemia Network (ELN) 2017 risk stratification system and transplant outcomes in the cytogenetic intermediate-risk group.

Methods: We performed a retrospective analysis of a total of 143 patients who diagnosed with cytogenetic intermediate-risk AML and received intensive standard ‘7+3’ chemotherapy for remission induction from 2012 to 2018 at Yonsei university Severance hospital in Korea.

Results: According to the ELN 2017 risk stratification system, 30 (21.0%), 80 (55.9%), and 33 (23.1%) patients were allocated to the molecular favorable, intermediate, and adverse risk group. The 5-year overall survival (OS) rate was 78.5% in molecular favorable group, 51.2% in molecular intermediate group, and 33.1% in molecular adverse group (P = 0.010) The 3-year progression free survival (PFS) rate in molecular favorable group were also significantly higher than those in intermediate and adverse group (85.3% vs 56.0% and 49.1%, P = 0.021). The outcome of allogeneic hematopoietic stem cell transplantation (HSCT) was evaluated in 124 patients who achieved complete remission. Among them, 71 (57.3%) patients received allogeneic HSCT as post-remission therapy, and the remaining 53 (42.7%) patients received consolidation chemotherapies only. Despite the higher proportion of patients receiving more than 2 cycle of induction chemotherapy (21.1% vs 5.7%, P = 0.016), the 3-year PFS was significantly higher in the transplant group than non-transplant group (71.2% vs 50.3%, P = 0.013). In molecular risk subgroup analysis, molecular favorable-risk subgroup showed about 80% PFS in both groups and transplantation did not show superiority (P = 0.853). In molecular intermediate-risk group, allogeneic HSCT resulted a longer PFS (P = 0.003) than chemotherapy as a post-remission treatment. For patients with molecular adverse-risk, poor prognosis could not be overcome neither chemotherapy nor transplantation (P = 0.198).

Conclusions: The molecular risk stratification of the ELN 2017 successfully distinguished long term prognosis in cytogenetic intermediate-risk AML patients and validated in our center. Because molecular evaluation using NGS technique recently became one of standard pre-treatment evaluation for AML patients in Korea, clinical benefit of HSCT should be carefully and precisely evaluated for cytogenetic intermediate-risk patients according to the molecular risk stratification. Furthermore, more effective post-remission treatment strategy should be determined especially for cytogenetic intermediate- and molecular poor-risk AML patients.

Clinical Trial Registry: This study was approved by the institutional review board of Severance Hospital (4-2010-0669, NCT 02344953).

Disclosure: There is no funding to declare.

P028 The Prognostic Significance of Minimal Residual Disease Monitoring by Wt1 Gene Expression in Peripheral Blood Before and after Allogeneic Stem Cell Transplantation in AML Patients

Veronika Valkova, Jan Vydra, Marketa Markova, Antonin Vitek, Ela Cerovska, Monika Belickova, Ludmila Novakova, Barbora Cemusova, Mariana Koubova, Petr Cetkovsky

Institute of Haematology and Blood Transfusion, Prague, Czech Republic

Background: The aim was to confirm our previous experience with prognostic relevance of WT1-MRD status before allo-SCT in AML patients in complete remission. Another aspect was to assess the significance of WT1-MRD monitoring in these patients after allo-SCT.

Methods: The expression of WT1 gene was measured by real-time polymerase chain reaction in peripheral blood according the European Leukemia Net recommendations. Between 2005-2019, we have analyzed 147 consecutive AML pts with high WT1 expression at diagnosis, transplanted in CR1 or CR2. Median age was 46 years (range; 21-66), 76 men, 21 good risk, intermediate risk 91, high risk 35. A total of 116 pts were transplanted in CR1 and 31 pts in CR2. In 128 pts PBPC were used, in 19 pts bone marrow. The donors were identical siblings in 30 pts, 9 haploidentical, matched unrelated donors in 73 pts and mismatched UDs in 35 pts. Conditioning was myeloablative in 117 pts, RIC in 30 pts. At the time of allo-SCT 107 pts were WT1-negative (WT1< 50 copies) and 40 pts were WT1-positive.

Results: Median follow-up was 21 months. Estimated 5-years OS and EFS was signifcantly better in WT1 neg cohort (65% and 57% vs 37% and 25% resp, p= 0,0003 and < 0,0001), as well as 5-years RI was significantly lower in WT1 neg group (25% vs 60%, p< 0,0001). 5-years NRM was not significantly different (24% and 27%). Multivariate analysis revealed WT1-MRD positivity and aGVHD grade 3-4 as a significantly negative prognostic factors for OS. Overall 50 pts developed WT1-MRD positivity in post-transplant period, in forty cases the therapeutical intervention was done. Haematological relapse occurred in 42 pts, in all relapsed patients where WT1-MRD was monitored (38 pts) we detected the positivity, in median of 28 days (0-485) before haematological relapse. 3-years OS in pts with molecular relapse only (12 pts) was 56% vs 74% in non-relapsed group (p=ns).

Conclusions: The results of the analysis confirmed our previous experience that WT1 status before allo-SCT is a strong prognostic factor for both OS and relapse risk. Our experience suggests that this marker is also useful for monitoring MRD after allo-SCT. Well-defined clinical studies will be needed to assess the importance of therapeutic intervention based on WT1-MRD positivity.

Disclosure: nothing to declare.

P029 Impact of Posttransplant Tyrosine Kinase Inhibitors Administration on Long Term Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in ph-positive Acute Lymphoblastic Leukemia Patients

Kseniia Afanaseva, Elena Morozova, Olga Pirogova, Yulia Vlasova, Anna Smirnova, Sergey Bondarenko, Ivan Moiseev, Boris Afanasyev

First Pavlov State Medical University of St. Petersburg, Saint-Petersburg, Russian Federation

Background: Widespread use of targeted therapy with tyrosine kinase inhibitors (TKIs) in combination with allogeneic hematopoietic stem cell transplantation (allo-HSCT) has dramatically improved therapy results in the majority of Ph-positive acute lymphoblastic leukemia (ALL) patients, so nowadays their survival may be comparable with Ph-negative ALL patients in most cases. Nevertheless, relapses remain a major cause of treatment failure even after allo-HSCT that lead to dismal prognosis. One of the possible strategies to prevent relapse includes posttransplant TKIs maintenance, but the data about its application regimens is still controversial. The aim of our study was posttransplant TKIs impact evaluation on outcomes of alloHSCT in Ph-positive ALL recipients.

Methods: This study analyses the data in retrospective cohort of 96 Ph-positive ALL patients with median age of 30 years (range, 18-57) undergoing allo-HSCT from HLA-matched sibling (n=24), haploidentical (n=12) or unrelated donor (n=60) in R.M.Gorbacheva Memorial Institute between 2007 and 2019. Median follow-up time was 24,8 months (range, 1-98 months). At the time of allo-HSCT 54 (56%) of patients were in first remission, 16 (10%) in second remission, 10 (16%) in third or subsequent remission, 16 (10%) in active disease (relapse/resistance/progression). 88 (92%) patients received 1st, 2nd or 3rd generation TKI prior to allo-HSCT. 36 (38%) patients were MRD-negative before allo-HSCT, while 39 (40%) had MRD-positive status, measured by PCR analysis. In posttransplant period 60 (63%) patients received TKIs (imatinib or dasatinib). The goal of posttransplant TKIs administration was prophylactic in 43 (72%) patients, preemptive in 8 (13%) and relapse treatment in 9 (15%). Median time of TKIs administration was 60 (range 30-125) days after allo-HSCT. Landmark analysis was used for comparison with patients without TKIs. Non-engrafted patients were excluded from analysis.

Results: 5-year OS and EFS were 59,4% and 45,8%, accordingly, whereas 5-year incidence of relapse was 35,4%. Comparing patients, who received posttransplant TKIs as prophylaxis with those, who did not receive prophylactic TKIs, we observed that 5-year EFS in 1st group was 63,3% vs 29% in 2nd (p< 0,001). 5-year incidence of relapse in 1st and 2nd groups were 51,6% vs.28,6%, accordingly (p< 0,001). We also estimated, that TKIs generation after allo-HSCT did not influence the results.

Conclusions: In our study 5-year EFS was twice better in patients, who received TKIs after allo-HSCT as prophylaxis, regardless the generation. Moreover, 5-year incidence of relapse was more than 20% lower in this group of patients. Thus, we can suggest that in order to reduce risk of relapse, it is preferable to prescribe TKIs no later than 60 days after allo-HSCT, before measurable residual disease appear, if there are no other factors that limit TKIs administration (toxicity of TKIs, poor graft function, etc.).

Disclosure: Nothing to declare.

P030 The Influence of anti-thymocyte Globulin(ATG) on the Outcomes of Patients with AML W/wo Measurable Residual Disease(MRD) at the time of Unrelated Donor Transplantation

Guldane Cengiz Seval, Ekin Kircali, Mehmet Akif Baltacı, Sinem Civriz Bozdag, Meltem Kurt Yuksel, Pervin Topcuoglu, Klara Dalva, Onder Arslan, Muhit Ozcan, Taner Demirer, Gunhan Gurman, Osman Ilhan, Hamdi Akan, Meral Beksac, Selami Kocak Toprak

Ankara University, Ankara, Turkey

Background: Anti-thymocyte globulin(ATG) is a very effective form of in vivo T-cell depletion and has been extensively used for GVHD prevention. However, ATG can potentially eliminate alloreactive donor T cells and reduce the graft-versus-leukemia(GVL) effect and increased disease relapse and reduced overall survival(OS). Herein, we aimed to investigate the impact of ATG on the outcomes of patients with AML stratified by flow cytometric MRD status who underwent Allo-HSCT from unrelated donor (UD).

Methods: This was a retrospective single center analysis using the data set of our institutional database. Eligibility criteria for this analysis included 75 adult patients with AML who underwent allo‐HSCT from either a HLA 10/10matched(n=34) or 9/10mismatched(n=41) UD, between October2012 and June2019. All recipients received peripheral blood stem cells grafts. Recipients of UD Allo-HSCT were routinely given rabbit Jurkat cell line-reactive ATG(ATG Fresenius®) in doses of 10mg/kg/day IV on days -3, -2, -1. Flow cytometry analyses were done using the flow cytometry system FACSCalibur(BD Biosciences, San Jose, CA) and sensitivity theresholds was 10-6. All analyses were done separately in patients achieving or not MRD negativity before transplant.

Results: A total of 75 consecutive patients with AML who underwent allo-HSCT from an UD were evaluated. Median age was 48 years(range:19-71) and 40(53.3%) were females. Median follow up from allo-HSCT was 9.8 months(4-80.9 months). There were 43 MRD-and 11 MRD+patients and 21 patients who were transplanted in the setting of active disease also included in this analysis. Fifty-five(73.3%) patients received myeloablative conditioning(MAC) and 20(26.7%) reduced-intensity conditioning(RIC) regimens. The most common MAC and RIC regimens were busulfan/cyclophosphamide(BuCy,60%) and busulfan/fludarabine(BuFlu,25.3%), respectively. The common GVHD prophylaxis were cylosporinA(CSA) and methotrexate(Mtx) in 64(85.3%) of the patients. Eight patients out of 21 patients with active disease underwent to allo-HSCT after FLAMSA-based high-dose sequential conditioning regimen. The use of ATG was associated with a lower incidence of chronic GVHD(18.7%). We investigated the influence of ATG on transplant outcomes separately in MRD-, MRD+and active disease cohorts. As expected, lowest incidence of relapse was observed in MRD- groups(MRD-; 23.3%(10/43) vs MRD+; 45.5%(5/11); p=0.168). MRD status at the time of allo-HSCT impact the leukemia free survival(LFS) significantly; MRD-(not reached) or MRD+(median 34.8(95% CI, 14.4-55.1)) or active disease(median 8.9 months(95% CI, 5.5-12.3))(p=0.021). In the group of MRD+patients, the OS was 21.6 months(95 % CI, 0.60-31.5) with 1- and 3- year OS rates of 72.7 ± 0.8 % and 31.2 ± 1.7 %, respectively(p=0.117). For the MRD-group, median OS after allo-HSCT was not reached versus 8 months in the active disease group(p=0.053). No outcome differences were found between MAC and RIC regimens. In addition, we did not find any association between type of HLA matched, relapse or GVHD incidences. Infection was the most common cause of death in the both groups.

Conclusions: Based on this single center study, the use of ATG was associated with a lower incidence of chronic GVHD. Most importantly, ATG could increase the risk of disease relapse or mortality in patients with pre-transplant MRD+and active diseases. However, further prospective, randomized studies on a large number of patients are warranted to clarify these findings.

Disclosure: Nothing to declare.

P031 MLL-AF6 Fusion Gene Positive AML Treated by Allogeneic Hematopoietic Stem Cell Transplantation has Excellent Overall Survival

Wei Ma, Xingyu Cao, Wei Zhang, Min Xiong, Jianping Zhang, Yue Lu, Ruijuan Sun, Zhijie Wei, Deyan Liu, Yanli Zhao, Jiarui Zhou

Hebei Yanda Lu Daopei Hospital, Sanhe, China

Background: Acute leukemia with MLL-AF6 fusion gene positive is the adverse factor of prognosis. The purpose of this study is to evaluate the outcome of allo-HSCT in the treatment of MLL-AF6 fusion gene positive acute leukemia.

Methods: The clinical characteristics and prognosis of 32patients with MLL-AF6 fusion gene positive acute leukemia from May 2012 to September 2019 were retrospectively analyzed. Twenty four patients received allogeneic hematopoietic stem cell transplantation, including 21patients with AML and 3 patients with T-ALL. 13 were males and 11 were females. Median age was 22(4-48) years old. The disease status before transplantation was CR1 (n = 10) CR2 (n = 2), NR (n = 12). The median time from diagnosis to HSCT was 24(4-352) months.

Patients underwent matched sibling donors HSCT (MSD-HSCT)(n=4), haploidentical HSCT (Haplo-HSCT)(n=20). The conditioning regimens are based on BU/Cy (n=20) and TBI/Cy (n=4). GVHD prophylaxis consisted of ATG, CSA, MMF and MTX.

Results: The number of mononuclear, CD34+ and CD3+ cells was (9.3±1.42)×108/kg, (4.1±1.1)×106/kg, and (1.6±0.5)×108/kg, respectively. White blood cells were successfully engraftment in 22 patients and the median time of ANC≥0.5×109/L was day 12(9-16). One patient failed to engraftment and one patient was not engraftment. Median time of platelet≥20×109/L was day 13(9-30) except 2 case. One patient failed to engraftment and one patient was not engraftment. DLI infusion was used to prevent recurrence in most patients after transplantation. The cumulative incidence of grade II - IV aGVHD was 41%, and the incidence of cGVHD was19%. Five-year overall survival(OS) rate and disease free survival(DFS) were 52.2% and 52% respectively. The five-year OS of allogeneic hematopoietic stem cell transplantation in CR1-2 and NR was 83.3% and 25%, respectively (P = 0.001). The mortality rate was 17% within 100 days. Transplant related mortality: 37%. Ten patients died, the causes of death were infection (n=2), IV aGVHD(n=3), and relapse(n=5). Eight patients received chemotherapy, all of them were AML patients, 5 males and 3 females, the median age was 26.5 (3-52) years old; eight AML patients were not relieved after the first chemotherapy, 3 patients only achieved remission after 2-4 chemotherapy, 5 patients were not relieved after multiple chemotherapy, 6 patients died, the cause of death: the primary disease was not relieved or relapsed; the overall survival was 2 cases. The OS rate was 52.2% in the transplantation group and 25% in the chemotherapy group (P = 0.237).

Conclusions: This study shows that MLL-AF6 acute leukemia has poor response to conventional chemotherapy and poorprognosis, so it is necessary to carry out allogeneic hematopoietic stem cell transplantation in remission state as early as possible.

Disclosure: Nothing to declare.

P032 Beneficial Outcome of Allogeneic Stem Cell Transplantation for Blastic Plasmacytoid Dendritic Cell Neoplasm

Ji Hyun Lee1, Seok Jin Kim2, Won Seog Kim2, Dok Hyun Yoon3, Cheolwon Suh3, Sung-Soo Yoon4, Youngil Koh4, Ja Min Byun5, Hyeon Seok Eom6, Hyewon Lee6, Jong Ho Won7, Ho Sup Lee8, Deok-Hwan Yang9, Ho-Young Yhim10, Ji Yun Lee11, Jae-Cheol Jo3, Yoo Jin Lee3,12

1Dong-A University, Busan, Korea, Republic of, 2Sunkyunkwan University, Seoul, Korea, Republic of, 3University of Ulsan, Seoul, Korea, Republic of, 4Seoul National University, Seoul, Korea, Republic of, 5Seoul National University Hospital, Seoul, Korea, Republic of, 6National Cancer Center of Korea, Goyang, Korea, Republic of, 7Soonchunhyang University, Soonchunhyang University Hospital,, Seoul, Korea, Republic of, 8Kosin University Gospel Hospital, Busan, Korea, Republic of, 9Chonnam National University, Hwasun, Korea, Republic of, 10Chonbuk National University, Jeonju, Korea, Republic of, 11Seoul National University Bundang Hospital, Seoul, Korea, Republic of, 12Ulsan University Hospital, Ulsan, Korea, Republic of

Background: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare aggressive hematologic neoplasm which originates from the professional type I interferon-producing cells or plasmacytoid monocytes. The prerequisite for its diagnosis is the CD4+ and CD 56+ co-expression without common lymphoid or myeloid lineage markers. Recently, targeted therapy with Tagraxofusp (SL-401), an IL-3 fusion protein which binds to CD123, has proved its efficacy with an overall response rate (ORR) of 90% in 32 untreated and 67% in 15 previously treated BPDCN patients. Although several retrospective and small case series has been published so far, there is few population-based study on BPDCN classified after 2008 WHO classification in Asian populati.

Methods: Data of 35 patients who were diagnosed with BPDCN from April, 2002 to February 2019 in 11 centers of South Korea were retrospectively collected and analyzed. Pathologic slides were reviewed in the central lab by the 2 pathologic experts and were finally confirmed for diagnosis. Overall survival was defined by the period from the date of the initial diagnosis to death by any cause or follow-up loss.

Results: The median age of the patients was 54.5 years (range, 17 - 84 years) with a male preponderance of 71.4% (25 of 35). 5 patients were preceded with hematologic malignancies. The most common initial presenting site was skin followed by lymph nodes, bone marrow, spleen, and liver. 32 of the included patients proceed to treatment with acute lymphoblastic leukemia (ALL)-like regimen (19 patients), acute myeloid leukemia (AML)-like regimen (5 patients) and lymphoma-like regimen (8 patients). Baseline characteristics of age ≥ 65 years, liver involvement and induction chemotherapy with lymphoma-like regimens expected worse prognosis in both univariate and multivariate analysis. Among the 32 patients who received induction chemotherapy, 11 cases proceeded to allogenic stem cell transplantation (SCT) and 3 received autologous SCT. With a median follow-up of 16.60 months (range, 0.53-79.73 months), patients who had been treated with leukemia-like induction regimen compared with lymphoma-like induction regimen (39.30 vs. 6.33 months, P=0.005) and allogeneic SCT compared with autologous SCT (54.13 vs. 7.70 months, P=0.015) showed markedly prolonged overall survival.

Conclusions: Induction treatment with leukemia-like regimen and proceeding to allogeneic stem cell transplantation can prolong overall survival in Asian patients with BPDCN.

Disclosure: There is nothing to declare.

P033 Nduction of Synergistic Apoptosis and Overcoming of Drug Resistance by Cotargeting of BCL-2 and Na/H Exchanger 1 Pathway in Acute Myeloid Leukemia Cells

Shin Young Hyun, Eun Jung Na, Ji Eun Jang, Haerim Chung, Soo Jeong Kim, Jin Seok Kim, Yoo Hong Min, June-Won Cheong

Yonsei University, Wonju, Korea, Republic of

Background: Anti-apoptotic proteins like Bcl-2, Bcl-Xl, or Mcl-1 play an important role in tumor cell survival and has been considered attractive drug targets. Especially, Bcl-2 selective inhibitor, venetoclax, has been showing significant effects on hematologic malignancies, but lower sensitivity and resistance gain have to be overcome to achieve durable response in acute myeloid leukemia (AML). Because intracellular pH is one of important modulators for Bcl-2 or Bax via deamidation process, in this study, we examined whether the cotreatment of Na/H exchanger 1 (NHE1) inhibitor, HMA [5-(N, N-hexamethylene)-amiloride] can overcome the resistance to venetoclax in AML cell lines.

Methods: Based on the preliminary experiments, venetoclax were treated to both venetoclax sensitive cell lines (MOLM13, MV4-11, and RS4-11) and venetoclax resistant THP1 cell line (THP1 and U937) with various concentration, and HMA was co-treated with 10 uM. Apoptotic cells were measured after 24 hr treated with each agent or combination. Apoptosis was analyzed using Annexin-V assay.

Results: As expected, venetoclax monotherapy induced concentration-dependent apoptosis in venetoclax sensitive MOLM13, MV4-11, and RS4-11 cells. For these cell lines, cotreatment of HMA to venetoclax synergistically potentiated apoptosis, and relatively lower concentrations of both drugs could induce almost complete apoptosis. For venetoclax resistant THP-1 and U937 cells, venetoclax could not induce sufficient apoptosis even with higher concentration. However, the combination treatment of HMA overcome venetoclax resistance, and induced apoptosis with 80% of THP-1 cells and 90% of U937 cells.

Conclusions: Our study suggests that co-targeting of Bcl-2 and NHE1 pathways not only sensitized the AML cells to venetoclax but also suggests that it could be one way to overcome venetoclax resistance in AML.

Disclosure: Nothing to declare.

P034 Gemtuzumab-ozogamicin for Bridging to Transplant in Refractory/relapsed CD33 Positive Acute Leukemia - is it Worthwhile?

Michael Stadler, Vanessa Oberstaedt, Elke Dammann, Lothar Hambach, Eva M. Weissinger, Catherina Lueck, Gernot Beutel, Matthias Eder, Arnold Ganser

Hannover Medical School, Hannover, Germany

Background: Outcome of allogeneic hematopoietic stem cell transplantation (alloHSCT) for acute leukemia (AL) is superior when performed in complete remission. Therefore, in refractory or relapsed patients not in remission after induction, consolidation or re-induction treatment, salvage strategies are being employed to reach at least marrow aplasia without residual blast morphology. Gemtuzumab-ozogamicin (GO), a humanized anti CD33 monoclonal antibody linked to calicheamicin, with a twisted drug history of early approval, withdrawal from the market, and renewed licensing for AML induction, has been an interesting candidate for such a strategy of “bridging to transplant” in CD33 positive AL patients.

Methods: We retrospectively evaluated overall (OS) and disease-free survival (DFS) of all adult refractory/relapsed AL patients having received GO for bridging to transplant at Hannover Medical School between 10/2004 and 12/2018. They were compared to a matched cohort of AL patients not reaching complete remission, but transplanted without bridging, since off-label GO could not be obtained for all refractory/relapsed patients.

Results: 232 refractory/relapsed AL patients underwent alloHSCT between 10/2004 and 12/2018 at our institution. 133 patients among them were CD33 positive. GO could be obtained for bridging to transplant in 32 patients, whereas 101 patients had to be transplanted without bridging. Both cohorts of CD33 positive patients were comparable for age, gender, disease subgroups, donor source, HLA matching, and conditioning intensity. GO salvage successfully induced marrow aplasia without residual blasts in 63% of evaluable patients. However, survival of CD33 positive AL patients after GO bridging (OS 29% at 5 and 10 years; DFS 27% at 5 years, 21% at 10 years) was not different from CD33 positive AL patients without GO bridging (OS 38% at 5 years, 28% at 10 years; DFS 32% at 5 years, 24% at 10 years). Of the total cohort of 232 refractory AL patients, 39% survived for 5 years and 32% for 10 years.

Conclusions: In our single center retrospective analysis of CD33 positive AL patients, bridging to transplant with GO seemed to have limited impact on long-term OS and DFS. However, even in refractory/relapsed AL, alloHSCT was able to rescue about one third of patients.

Disclosure: No conflicts of interest.

P035 Azacytidine and Donor Lymphocytes Infusions in Relapsed AML after Allogeneic Hsct: Results in 40 Patients

Carmine Liberatore, Francesca Lorentino, Matteo Giovanni Carrabba, Carlo Messina, Luca Vago, Sara Mastaglio, Raffaella Greco, Francesca Pavesi, Sarah Marktel, Francesca Farina, Raffaella Milani, Consuelo Corti, Massimo Bernardi, Jacopo Peccatori, Maria Teresa Lupo Stanghellini, Fabio Ciceri

IRCCS San Raffaele Scientific Institute, Milan, Italy

Background: azacytidine (AZA) alone or with donor lymphocytes infusions (DLI) is an option for the treatment of acute myeloid leukemia (AML) relapsing after allogeneic stem cell transplantation (HSCT).

Methods: according to institutional policy, from 2012 to 2019 we treated 40 patients with AML relapsed after HSCT with AZA +/- DLI. Indications were either minimal residual disease positivity (MRD+) (evaluated by qPCR, flow cytometry or cytogenetical analysis) or morphological relapse not eligible for intensive chemotherapy. AZA dosage ranged from 32 mg/mq G1-5 to 75 mg/mq G1-7 q28 days. DLI was given every 2 cycles of AZA at escalating dose as per institutional guidelines. Indication to DLI relied upon clinical-biological features of patient, disease and HSCT (active GvHD and HLA loss were contraindications).

Results: clinical-biological features at baseline and at relapse are reported in Figure 1. Median time from HSCT to relapse was 10 months (range 1-55). Fourteen patients had MRD+ (group 1) and 26 patients had morphological relapse (group 2). Nine patients (23%) received AZA 32 mg/mq while 31 patients (77%) received AZA 75 mg/mq. Median number of AZA cycles was 4 (range 1-28). Sixteen patients (40%) received AZA+DLI, median number of DLI was 2 (range 1-4), median amount of CD3+ cells/Kg per patient was 3,8 x10^6 (range 0,1-76).

Overall response rate was 55% (22 pts): 57% (8 pts) in group 1 vs 54% (14 pts) in group 2 (p=0.87). Complete response rate was 33% (13 pts): 43% (6 pts) in group 1 and 27% (7 pts) in group 2 (p=0.43).

Progression free survival (PFS) at 1-year was 32%: 57% in group 1 vs 19% in group 2. At 2-years PFS was 23%: 57% in group 1 vs 7% in group 2 (p=0.01). In group 1, 7 patients maintained CR (4/7 received DLI) after a median follow up of 22 months (range 11-64). In group 2, 1-year PFS in patients with < 20% blast at relapse was 22% vs 12% in patients with ≥20% (p=0.24).

Overall survival (OS) at 1 year was 60%, respectively 85% in group 1 vs 46% in group 2. At 2-years OS was 41%: 77% in group 1 vs 22% in group 2 (p=0.01).

Most common grade 3-4 adverse events were neutropenia (80%), thrombocytopenia (55%), anemia (45%) and febrile neutropenia (35%). Acute GvHD developed in 3 patients (no one had previous GvHD, 1 received DLI) while 5 patients had chronic GvHD (2 had previous acute GvHD, 2 had previous chronic GvHD, 1 received DLI). No patient died because of treatment.

Conclusions: AZA +/- DLI is a feasible salvage therapy in relapsed AML after HSCT. AZA +/- DLI was rarely curative in morphological relapse - independently by blast counts - while long-term remissions were achieved in patients treated for MRD+ after transplant.

Disclosure: Nothing to declare.

P036 The Results of AML Relapse after Allogeneic Transplantation Treatment, Single Centre Approach Evaluation

Markéta Šťastná Marková, Veronika Válková, Antonín Vítek, Ludmila Nováková, Barbora Čemusová, Michal Kolar, Jan Vydra, Petr Cetkovský

Institute of Hematology and Blood Transfusion, Praha, Czech Republic

Background: Although allogeneic transplantation brings a substantial survival benefit in AML, post-transplant relapse remains one of the major events leading to treatment failure. Together with non-existing definite approach guidelines it causes difficulties in further treatment decision.

Methods: A retrospective survival evaluation of relapsed AML (n=148) patients after allogeneic transplantation between the years 1990 and 2019 was done. The decision of relapse treatment was performed individually with the respect to biological parameters of the disease, patient´s physical status and will. For the evaluation purpose the whole cohort was divided to 3 groups -1) no chemotherapy treatment except of immunosuppression tapering and DLI administration (n=44), 2) “low intensity “ treatment including low dose ARA-C, 5-azacytidine with immunosuppression modification and with or without DLI administration (n=36) and 3) “high intensity” treatment including intensive regimens with high dose ARA-C and anthracyclines preferentially with DLI or second transplant (n=68).

Results: The overall survival in 1, 2 and 5 years was 32%, 20% and 16%. There was an expected significant difference between not treated group (2%, 1%, and 1%) and treated group with no significant further difference between low intensity and high intensity groups (48%, 29% and 16% in high intensity group and 31%, 21% and 16% in low intensity group). Patients who relapsed earlier from transplant did worse in the first two years, but the difference disappeared in surviving patients after 24 months of relapse treatment. Not surprisingly patients who had achieved complete remission had significant OS advantage (71% vs 6% in 1 year and 52% vs 1% in 2 years). There was no survival advantage in treated patients without remission achievement to untreated patients at all, though among untreated patients there was one (1/36) fully responding to immunosuppression tapering. 34% of patients with remission achievement relapsed again. Treatment toxicity related death was in 21%. Another major contributor to death was GVHD.

Conclusions: The outcome of AML patients relapsing after allogeneic transplantation is very poor despite various treatment approaches. The survival benefit was seen in patients who achieved further remission, though the subsequent relapses were frequent. Treatment toxicity was rather high in this group of patients. The emphasis on prophylactic and preemptive treatment together with tight minimal residual disease monitoring should be carried out, and the introduction novel drugs (e.g. venetoclax, gilteritinib etc.) should be evaluated.

Disclosure: Nothing to declare.

P037 Allogeneic Hematopoietic Stem Cell Transplantation for Relapsed or Refractory Acute Myeloid Leukemia: A Single Center Analysis

Paul Deschamps, Claude-Éric Bulabois, Martin Carré, Anne Thiebaut-Bertrand, Jean-Yves Cahn

CHU de Grenoble, La Tronche, France

Background: Approximately 60-70% of adult patients with newly diagnosed acute myeloid leukemia (AML) will achieve a complete remission after induction regimen. However resistant disease or relapse (R/R) remain a significant cause of treatment failure and a major unfavorable prognostic factor. Role and timing of allogeneic hematopoietic stem cell transplantation (HSCT) remains a matter of debate for these patients with R/R AML, as well as their transplant outcome. For these reasons, we have retrospectively analyzed the outcome of adult patients who underwent HSCT for R/R AML in our center at Grenoble University Hospital from 2007 to 2017.

Methods: Adults who had received HSCT in our center between 01/01/2007 and 12/31/2017 for R/R AML, at time of transplantation, were included. Progression-free survival (PFS) was the primary end point, while secondary endpoints assessed overall survival (OS), graft-versus-host disease (GVHD) relapse-free survival (GRFS), and cumulative incidences of GVHD, relapse and non-relapse mortality (NRM).

Results: This retrospective study reports data from 56 patients receiving HSCT for de novo or secondary R/R AML. The median age at transplantation was 56 years (range, 20-69 years). Median of marrow blasts was 13% (range, 5,5-78%). Half of the cohort underwent a myeloablative conditioning regimen, while 29% of the patients received a sequential regimen approach. Median follow-up was 52 months for surviving patients (range, 24-132 months), and the PFS at 1 year was 21,4% (95% Confidence Interval [CI], 11,9-32,9%), with a median of 98 days (95% CI, 64-149 days). Overall survival was 25% (95% CI, 14,6-36,8%) at 1 year, GRFS was 10,7% at 1 year (95% CI, 4,4-20,4%). Cumulative incidence of acute GVHD II-IV reached 47,8% including 13,6% of grade III-IV at 1 year, while 28,6% of patients were reported for chronic GVHD. Twenty four per cent of patients had a refractory disease at first assessment after HSCT. Relapse incidence was 62,7% (95% CI, 49,1-76,3%) at 1 year and progression of the disease was responsible for 53% of the whole cohort mortality. 88,5% of relapses occurred within the 6 first months following HSCT, and none appeared after the 8th month. NRM at 1 year was 32% (95% CI, 9,9-51,5%).

Conclusions: This study confirms the role of HSCT in R/R AML patients as the best curative approach available today, with similar outcome rates than previously published. No specific subgroup of patients was identified in terms of better outcome. However, the high incidence of early post-transplantation relapse reveals the persistent need to improve the procedure. The key points reported in larger trials are early donor identification, easier with the availability of haplo-donors, use of sequential conditioning regimen, early tapering of immunosuppression and post-transplantation maintenance, such as targeted therapies, hypomethylating agents, donor lymphocytes infusions or other forms of immunotherapies.

In conclusion allogeneic HSCT remains feasible in this poor prognosis subgroup of AML and a multicentric program is underway in Auvergne-Rhone-Alpes region, France, based on the harmonization of HSCT practices in this very high-risk AML patients.

Disclosure: No disclosure to declare.

P038 The Optimal Time for Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Acute Myeloid Leukemia

Sergey Bondarenko, Ivan Moiseev, Elena Morozova, Olga Pirogova, Elena Darskaya, Anna Smirnova, Nikolai Tsvetkov, Anastasiya Beynarovich, Irina Samorodova, Tatyana Gindina, Elena Babenko, Ildar Barkhatov, Alexander Alyanskiy, Alexander Kulagin, Boris Afanasyev

First Pavlov State Medical University of St. Petersburg

Background: AML is the most common indication for alloHSCT. The EBMT manuscripts estimate the intermediate-risk ELN2017 patients as candidates for alloHSCT in CR1 from MSD. AlloHSCT from MUD is still a clinical option for this prognostic group. However, the outcome of relapsed AML remains poor, both due to low incidence of achieving a CR2 and higher NRM.

Methods: The study included 298pts for the period 2005-18, median(m) age was 36(18-70)years. The m follow-up was 24(13-168)months. Disease status: CR1 - 234(78%)pts, CR2 - 64(22%)pts. The favorable risk group(fav) included 50(17%)pts, the intermediate(int) - 200(67%)pts, and the unfavorable(unfav) - 48(16%)pts. AlloHSCT underwent 242pts, 178(74%)pts in CR1, according to ELN2017 fav - 21(12%)pts, int - 121(68%)pts and unfav - 36(20%)pts; in CR2 - 64(26%)pts, which were fav - 16(25%)pts, int - 36(56%)pts and unfav - 12(19%)pts. In int group alloHSCT was performed from MSD in 36pts and from MUD - 85pts. Chemotherapy (CT) received 56pts in the CR1 - 13(23%)pts in fav and 43(77%)pts in int ELN2017. Since 2013 PTCy has been used for the prevention of GVHD in alloHSCT and, since 2016 MAC consisted of fludarabine and busulfan14mg/kg.

Results: OS and RFS in fav were: after CT - 78%(95%CI57-99) and 72%(95%CI53-99), after allotHSCT in CR1 - 76%(95%CI59-95) and 71%(95%CI51-91), in CR2 - 86%(95%CI73-99) and 71%(95%CI48-94), p=.7 and p=.9. Relapse rate(RR) and NRM were 28%(95%CI6-56) and 10%(95%CI1-39), 24%(95%CI8-44) and 5%(95%CI1-20), 22%(95%CI5-48) and 13%(95%CI2-35), p =.6.

In int OS and RFS were: after CT - 42%(95%CI17-67) and 34%(95%CI15-53), after alloHSCT in CR1 - 77%(95%CI70-84) and 72%(95%CI65-79), in CR2 - 46%(95%CI27-65) and 45%(95%CI31-59), p=.02 and p=.03. RR and NRM - 60%(95%CI38-77) and 6%(95%CI6-19), 16%(95%CI10-25) and 12%(95%CI7-18), 26%(95%CI11-43) and 29%(95%CI15-45), p=.09 and p=.06.

After alloHSCT in unfav OS and RFS in CR1 were 43%(95%CI26-60) and 34%(95%CI17-51), in CR2 - 31%(95%CI4-58) and 30%(95%CI3-57), p=.4. RR and NRM were 60%(95%CI40-75) and 6%(95%CI1-17), 52%(95%CI18-77) and 18%(95%CI2-47), p=.8 and p=.2.

In int the year of alloHSCT was evaluated 2005-12 vs 2013-18. In CR1 the OS, RFS, RR and NRM were 64%(95%CI51-77) vs 85%(95%CI78-92), p=.01, 62%(95%CI48-76) vs 76%(95%CI64-88), p=.05, 20%(95%CI10-33) vs 16%(95%CI7-29) and 18%(95%CI8-30) vs 8%(95%CI3-16). In CR2 OS, RFS, RR and NRM were 30%(95%CI8-52) vs 65%(95%CI44-86), p=.3, 29%(95%CI7-51) vs 64%(95%CI42-86), p=.2, 34%(95%CI13-57) vs 12%(95%CI2-32) and 33%(95%CI13-55) vs 23%(95%CI7-45). In case of MSD 2005-12 vs 2013-18 in CR1 OS, RFS, RR and NRM were 58%(95%CI32-83) vs 78%(95%CI60-96), p=.2, 54%(95%CI29-79) vs 59%(95%CI34-84), p=.5, 32%(95%CI11-55) vs 36%(95%CI12-61) and 14% (95%CI2-36) vs 5% (95%CI1-21). After MUD alloHSCT 2005-12 vs 2013-18 in CR1 OS, RFS, RR and NRM were 67%(95%CI51-83) vs 87%(95%CI79-95), p=.07, 67%(95%CI50-84) vs 81%(95%CI67-95), p=.07, 13%(95%CI4-28) vs 10%(95%CI2-26) and 20%(95%CI8-36) vs 9%(95%CI3-18).

Conclusions: AlloHSCT should be delayed to CR2 for patients in the favorable risk group. In the unfavorable group, alloHSCT is indicated in CR1. Given the improvement of transplantation methods for patients of the intermediate group, alloHSCT is recommended in CR1. The outcome of alloHSCT from matched unrelated donor comparable with matched sibling donor. Patients with intermediate ELN risk AML should perform alloHSCT in CR1 despite of donor type (MSD or MUD).

Disclosure: Nothing to declare.

P039 Impact of ABO Mismatch Allogeneic Transplant in Acute Myeloid Leukemia -A Single Centre Experience

Fahad Shaikh, Ganapathi Bhat, Suresh Advani, Samir shah, Reetu Jain

Jaslok Hospital and Research Center, Mumbai, India

Background: Post remission therapy in patients with acute myeloid leukemia (AML) consist of giving maintenance chemotherapy or allogeneic hematopoietic stem cell transplantation (AlloHSCT) in high risk patients as a curative therapeutic option. Conflicting results have been reported on the impact of ABO mismatch on various transplant outcomes such as neutrophil and platelet engraftment, acute and chronic graft versus host disease (GvHD), non-relapse mortality and overall survival.

Methods: We analyzed data of 58 AML (Acute Myeloid Leukemia) patients who had undergone Allo HSCT, between 2005 to 2019, at our Centre. In this study, we evaluated the demographic and clinical characteristics of patients, the effect of ABO mismatch and graft source on HSCT outcomes, such as engraftment and graft versus host disease (GvHD)

Results: Out of 58 patients, 30 (51%) were males, 28 patients were female. The median age was 31 years (range 3- 60) years. PBSC was the major source of graft, and matched sibling were the predominant donor type (97.1%). There were 26 patients with gender mismatch (44.8%). Among the recipients, ABO group mismatch was seen in 15 patients (25.8%), of which 12 cases were major blood group mismatch. Majority of patients received Bu-Cy as conditioning regimen (65.5%). The mean time to neutrophil engraftment was 14.6 days (SD 3.08) and platelet engraftment was 15.8 days (SD 4.69), which were similar in all patients irrespective of ABO match/mismatch status. (p=0.04 and p=0.05 respectively). 75.5% patients developed febrile neutropenia, of which 15% had documented infection with an identifiable microorganism. 13 cases (22.4%) developed acute GvHD, while 4 cases had VOD. 3 patients had transplant related mortality. Patients with fully matched sibling donor had statistical significant association with improved survival outcome (p 0.017). Both major and minor blood group mismatch were associated with increased mortality (p=0.05). On comparing different variables in terms of standard deviation using unpaired t test, age at transplant was the only variable with significant association with survival outcome (p.0.003).

Conclusions: Our experience with ABO mismatch is encouraging with good tolerability and disease control even in the advanced stage heavily pre-treated patients. More aggressive strategies including second transplants and novel agents are needed in these patients on relapse.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (7)

[overall survival]

Disclosure: No conflict of interest. This study was not funded

P040 Donor Source Impacts on Long Term Survival following Reduced Intensity Allogeneic Stem Cell Transplant in AML Patients Aged 60 and Above

William Hayhurst, Asterios Giotas, Chloe Anthias, Sandra Easdale, David Taussig, Mike Potter, Mark Ethell, Joy Brennan, Maria Mulligan, Kim Davis, Emma Thistlethwayte, Emma Nicholson

Royal Marsden Hospital, London, United Kingdom

Background: Outcomes in elderly AML remain poor due to high risk of relapse, higher incidence of adverse cytogenetics and of chemotherapy resistance. The advent of reduced intensity conditioning (RIC) regimens has led to increasing use of allogeneic transplant in patients over the age of 60. This can lead to durable disease free survival in this age group and improved outcomes compared to that achieved with chemotherapy alone

Methods: This retrospective study analysed outcomes of 100 consecutive patients over the age of 60 years old undergoing RIC SCT for AML between June 2006 and June 2018. Patients were conditioned with Fludarabine/Melphalan/Alemtuzumab (n=94) or Fludarabine/Cyclophosphamide/2GyTBI (n=6). Data was collected from Electronic patient records. Probability of Overall Survival (OS), Progression Free Survival (PFS) were calculated by Kaplan Meier method and log rank test performed. Cumulative Incidence (CI) of relapse risk (RR), non-relapse mortality (NRM) and GVHD was calculated using competing risk analysis

Results: 100 patients were included in the study with a median age of 65 years (range 60-1 - 71.8). 77% had De Novo AML, 13% had a preceding diagnosis of MDS or MPD, 10% had therapy related AML. 79% of the patients were transplanted in CR1 and 21% were transplanted in CR2. 34 patients relapsed at a median of 0.96 years post transplant (range 0.11-5.37). 53% of patients had a matched Unrelated Donor (MUD) SCT, 23% sibling donor, 18% Mismatched unrelated donor (MMUD) and 6% umbilical cord blood (UCB) donor. 39% of patients had adverse prognostic markers at diagnosis as per ELN 2017 guidelines.

2 year OS was 41% and 2 year PFS was 36%. RR at 2 years was 25% and 2 year NRM was 38%. CI of Grade 2-4 acute GVHD at Day 100 was 15% (9-23) and 2 year CI of chronic GVHD was 30%. 2 year OS for patients with sibling, MUD, MMUD and cord donors was 61%, 40%, 67% and 22% respectively and 2 year PFS for patients with sibling, MUD, MMUD and cord donors was 56%, 35%, 67% and 17% respectively. OS was significantly reduced in those with MMUD donors compared to sibling (p=0.009%) and MUD donors (p=0.04%) due to higher NRM. Age at transplant (< 65 years versus >/=65 years), transplant in CR1 versus CR2 and adverse versus non adverse risk group had no significant impact on OS or PFS.

Conclusions: T cell depleted RIC allogeneic HSCT can lead to durable disease free remissions in older patients with AML including patients with adverse risk disease or therapy related or secondary AML. Patients with MMUD had inferior OS and PFS compared to those with a sibling or MUD donor in this age group and the decision to perform a mismatched unrelated donor transplant in this age group should be carefully assessed. Whilst numbers of UCB were small, the of use of alternative donors rather than MMUD in this age group should be considered and warrants further evaluation in randomised setting

Disclosure: Nothing to declare.

P041 Extra-medullary Recurrence of Acute Myeloid Leukemia as Myeloid Sarcoma after Allogeneic Stem Cell Transplantation: A Case Series

Jochen Frietsch1, Friederike Hunstig1,2, Sebastian Scholl1, Andreas Hochhaus1, Inken Hilgendorf1

1Universitätsklinikum Jena, Jena, Germany, 2Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany

Background: Myeloid sarcoma (MS) as a solid extra-medullary manifestation of acute myeloid leukemia (AML) is a rare presentation of relapse after allogeneic hematopoietic stem cell transplantation (HSCT). It may occur as an isolated extra-medullary relapse, multilocular or in association with a medullary relapse.

Methods: All patients aged 18 years or older who have received HSCT for AML at our center since 2002 (n = 327) were screened for onset of MS after HSCT. Of those, 12 patients (3.7%) suffered from MS as extra-medullary relapse after HSCT and were included in this study.

Results: We identified 12 patients (median age 53 years) with MS. They all received reduced intensity conditioning (RIC). 58.3% (7/12) received HSCT from a matched-unrelated, 33.3% (4/12) from a matched-related and 8.3% (1/12) from a mismatched-related donor. The median onset of MS was 490.5 days after HSCT (range: 134 and 1276 days). The regions and organs affected varied from very typical tissues such as skin, bone or lymph node up to extremely rare presentations of MS affecting the pituitary gland, breast tissue, the thoracic wall or the paranasal sinuses. Eight (66.7%) patients developed MS despite a history of graft-versus host-disease (GvHD).

Concerning the treatment, various therapy options were considered. The most frequently applied treatment options were intrathecal triple therapy, cytarabine and azacytidine. None of the patients received another HSCT. Irradiation was implemented where possible. Although MS is associated with a poor prognosis, three patients (3/12) survived more than two years and one more than 11 years after diagnosis of MS. The median overall survival since diagnosis of MS was 255.5 days (Kaplan-Meier).

Conclusions: These observations demonstrate the limitations of graft-versus-tumor effects after HSCT, since extra-medullary relapse did occur in the presence of GvHD. The results may also indicate that reduced intensity conditioning protocols are associated with a higher rate of extra-medullary relapse.

Single isolated manifestations are more frequently treated successfully compared to multilocular manifestations of MS. This is in part due to fewer issues regarding accessibility by local therapies such as irradiation or intrathecal therapy (in cases of involvement of the central nervous system). Altogether occurrence of MS after HSCT is associated with a poor prognosis as curative concepts including intensive chemotherapy and another HSCT are often not viable.

Disclosure: The authors do not declare. any conflicts of interest.

P042 Allogeneic Stem Cell Transplants in Acute Myeloid Leukaemia; A Single Centre Experience

Tomas Kupsa1,2, Jan Vanek2, Benjamin Visek1, Miriam Lanska1, Alzbeta Zavrelova1, Ladislav Jebavy1,2, Jakub Radocha1, Jan M Horacek1,2, Pavel Zak1

1Charles University Prague, Hradec Kralove, Czech Republic, 2University of Defence, Hradec Kralove, Czech Republic

Background: Allogeneic stem cell transplant remains the best consolidation therapy in intermediate and high-risk AML patients with a suitable donor. We conducted a retrospective analysis to identify those who may benefit from further intensification of therapy.

Methods: Eighty patients, aged 53.5 ± 12.6 years, diagnosed in period 2010-2016 were studied. All were treated with a curative approach with “3+7” induction therapy, followed by consolidation only of allogeneic stem cell transplantation. All living patients have been observed for at least two years. The FLT3 inhibitors were not used in this cohort.

Results: 55 patients (69%) achieved complete remission (CR) by induction therapy. 57 patients (71%) were allografted. Hematologic relapse (P < 0.001), high-risk cytogenetics (P = 0.001) and age (P = 0.033) influenced overall survival (OS). Patients relapse-free for at least two years (irrespective of consolidation by chemotherapy only or allografted) had low risk of relapse and longer OS (P < 0.001). Allografted patients were younger (P = 0.009) and had improved OS (P = 0.010). Patients aged ≥ 65 years had lower probability of prolonged remission and inferior outcome. Primary induction failure (PIF) in low- and intermediate risk AML (n = 8/47, 17%) was not associated with inferior OS. In high-risk AML and PIF (n = 14/33, 42%) the median OS was 6.7 months in the whole cohort, respectively 12 months in 8 allografted individuals.

Conclusions: In patients with low- and intermediate risk AML and PIF the allogeneic stem cell transplant may overcome the resistance to induction therapy. A substantial proportion of PIF patients have high-risk AML. The efficacy of allogeneic stem cell transplant is limited in this cohort and the overall survival is poor. These patients may most benefit from innovative treatment approaches.

The work was supported by program PROGRES Q40/08, and by DZRO 1011 (FMHS).The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (8)

[PIF in high-risk AML]

Clinical Trial Registry: Not applicable.

Disclosure: Nothing to declare.

P043 Allogeneic Hematopoietic Cell Transplantation for Patients with Acute Myeloid Leukemia not Responding to First Induction Therapy

Annalisa Natale1, Stefano Angelini1, Mauro Di Ianni1, Gabriele Papalinetti1, Doriana Vaddinelli1, Paolo Di Bartolomeo1, Giuseppe Calabrese2, Stella Santarone1

1Unità di Terapia Intensiva Ematologica per il Trapianto Emopoietico, Ospedale Civile, Pescara, Italy, 2Laboratorio Genetica Molecolare Onco-Ematologica, Ospedale Civile, Pescara, Italy

Background: Patients with acute myeloid leukemia (AML) who did not achieve remission after first induction chemotherapy have a dismal prognosis. Prior reports have shown that these patients could be rescued with allogeneic hematopoietic cell transplantation (HCT). The aim of this retrospective study was to determine the clinical outcome of 34 AML patients who failed first induction chemotherapy and were treated with HCT (n=40) in our center between June 1995 and April 2019.

Methods: 34 patients with AML who did not achieve complete remission (CR) after first induction chemotherapy with “7+3” regimen (cytarabine associated to either daunorubicin or idarubicin) were enrolled in this study. As second induction chemotherapy, most patients received high dose cytarabine-based regimen. The median number of chemotherapy lines before transplantation was 2 (range, 2-3). The median time from diagnosis to first CR was 106 days (range, 63-225). At time of HCT, 30 patients were in CR1, 2 in CR2 and 2 in partial remission (marrow blasts 6-10%). Table 1 shows some characteristics of patient population at time of first transplant.

Results: Full engraftment of donor cells was evident in 31 evaluable patients (91%). 2 patients died before engraftment and 1 patient showed primary graft failure. The median time to reach >0.5 x109/L neutrophils was 23 days (range, 13-35). The CI of either acute (grade II-IV) or chronic (limited + extensive) GvHD was 32% and 21% respectively. Leukemia relapse occurred in 13 patients at a median of 411 days (range, 67-1824) after transplant for a CI of 42%. Of them, 5 died for leukemia, 6 underwent a second transplant after achieving second CR, 1 is waiting for second HCT and 1 is leukemia-free after sorafenib therapy. Among 6 patients who received a second transplant, 2 are living and cured, 2 died for infections, 1 died for VOD and 1 died for leukemia relapse. Nine patients died for transplant-related causes at a median of 53 days (range, 8-740) after transplant. Causes of death were infection in 5, acute GvHD in 2, and heart failure in 2. The 3-year-CI of transplant-related mortality was 27%. As of November 2019, 16 patients are living and doing well after a median follow-up of 116 months (range, 7-264). Of them, 15 (44%) are cured and 1 is waiting for second transplant. The 5-yr Kaplan-Meyer overall survival and disease-free survival were 47% and 29% respectively.

Conclusions: This study demonstrates that allogeneic HCT may produce durable remission and cure in patients with AML who failed first induction chemotherapy.

N. of patients/ transplants34/40
Gender, male/ female20/14
Median age, years (range)44 (5-66)
2017 ELN risk: favorable/intermediate/adverse/not determined2/17/6/9
Donors: HLA id sibling/unrelated/haploidentical12/11/11
Stem cell source: BM/PBSC/CB23/10/1
Conditioning: MAC/RIC27/7
Conditioning: TBI/Busulfan/Melphalan/Treosulfan/Thiotepa3/27/2/1/1
GvHD prophylaxis: CSA/CSA+MTX/T-reg2/31/1

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[Table 1]

Disclosure: Nothing to declare.

Aplastic anaemia

P044 Salvage Allogeneic Hematopoietic Stem Cell Transplantation for Severe Aplastic Anemia Patients with Refractory Active Infection: A Prospective Multicenter Clinical Study in China

Xia Qin1, Xiangfeng Tang2, Yiping Zhu3, Rongmu Luo4, Ting Yang5, Zimin Sun6, Shaoyan Hu7, Yuan Sun8, Shunqing Wang9, Weiping Zhang10, Xianmin Song11, Jiong Hu12, Ke Huang13, Jing Chen1

1Shanghai Children’s Medical Center, National Children’s Medical Center, Shanghai, China, 2The Sixth Medical Center of PLA General Hospital, Beijing, China, 3West China Second University Hospital/West China Women and Children’s Hospital, Chengdu, China, 4BaYi Children’s Hospital, The Seventh Medical Center of PLA General Hospital, Beijing, China, 5Fujian Medical University Union Hospital, Fuzhou, China, 6Anhui Provincial Hospital, University of Science and Technology of China, Hefei, China, 7Children’s Hospital of Soochow University, Soochow, China, 8BeiJing JingDu Children’s Hospital, Beijing, China, 9Guangzhou First People’s Hospital, Guangzhou, China, 10Changhai Hospital, Naval Medical University, Shanghai, China, 11Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, 12Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, China, 13Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China

Background: It is generally recognized that allogeneic hematopoietic stem cell transplantation (allo-HSCT) should not be managed to patients with active infection. However, in patients with severe aplastic anemia (SAA) especially very severe aplastic anemia (VSAA), it is usually difficult to control the infection without neutrophil. Rapid recovery of neutrophil by allo-HSCT might be a salvage treatment to control infection and rescue the patients. To evaluate the efficacy of allo-HSCT for SAA patients with refractory active infection, we designed this multicenter prospective clinical study in China.

Methods: Refractory active infection was defined as persistent fever without response to broad-spectrum antibacterial and antifungal treatment for more than three weeks with or without a definite infected site, or there was a definite infected site with fever less than 3 weeks. The probabilities of overall survival (OS) were calculated using the Kaplan-Meier estimator and compared between two groups using the log-rank test. The cumulative incidences were calculated using competing-risk models and analyzed by the Grey test between groups.

Results: Totally 75 patients were enrolled in this study from April 2014 to July 2018. All patients had persistent fever, including 52 (69.3%) with pneumonia (13 also accompanied with other site infection), 16 (21.3%) with other site infection and another 7 (9.3%) without a definite infected site. 51 (68.0%) patients received HSCT from a haploidentical family donor, 15 (20.0%) from an unrelated donor and only 9 (12.0%) from a sibling donor. For the prompt engraftment, peripheral blood stem cells (PBSCs) were given to all of our patients. Meanwhile, bone marrow was co-transplanted with PBSCs in 40 (53.3%) patients. The median age was 6.3 years (range, 1.0-38 years). Seven (9.3%) patients died of infection before engraftment. Two (2.7%) patients got primary mixed chimerism at day 28, and one developed secondary graft failure. The other patients sustained complete donor chimerism after HSCT. The median time for myeloid engraftment was 13 days (range, 9 to 32). The cumulative incidences (CI) of II-IV acute GVHD and chronic GVHD were 18.7±4.5% and 24.0±5.0% respectively. With a median follow-up of 730 days (range, 2 to 1568), the probability of OS was 77.2±4.9%. Because 68% of patients underwent haploindetical transplant, we compare the outcomes of patients receiving haploindetical transplant with active infection (n=51) to that of patients receiving haploindetical transplant without active infection (n=73) during the same period. There were no statistic differences in the CI of II-IV acute GVHD (17.6±5.4% vs 19.2±4.6%, p=0.771), CI of chronic GVHD (25.5±6.2% vs 20.5±4.8%, p=0.371), and the probability of OS (78.3±5.8% vs 89.0 ±3.7%, P=0.096) between the two groups. Compare to the other donor, the FFS II-IV, aGVHD and chronic GVHD with haploidental donor HSCT is simila to other donors.

Conclusions: Allo-HSCT is a feasible therapeutic option for SAA patients with refractory active infection. Haploidentical family donor is a good donor if without matched sibling donor. Peripheral blood stem cell may be the better graft source for this salvage HSCT owing to the rapidly engraftment.

Clinical Trial Registry: Clinical Trail registry number: ChiCTR-OCH-14005190

http://www.chictr.org.cn

Disclosure: Nothing to declare.

P045 Incidence and Management of Aplastic Anemia in Spain (IMAS). An Ambispective Study of Biodonostia / Pethema

Carlos Vallejo1, Ana Rosell2, Blanca Xicoy3, Carmen García4, Carmen Albo5, Marta Polo6, Isidro Jarque7

1University Hospital Donostia, Donostia, Spain, 2Hospital Virgen de la Victoria, Málaga, Spain, 3ICO-Hospital Germans Trias i Pujol, Badalona, Spain, 4Hospital General de Alicante, Alicante, Spain, 5Hospital Álvaro Cunqueiro, Vigo, Spain, 6Hospital Clínico San Carlos, Madrid, Spain, 7Hospital La Fe, Valencia, Spain

Background: Aplastic anemia (AA) is a rare, and life-threatening hematological disease. It is known that its incidence and prevalence might vary substantially among different geographic regions, and its presentation has been sometimes linked to environmental exposures. Montané et al reported an incidence of 2.34 per million inhabitants per year in the metropolitan area of Barcelona (Haematologica 2008). In the north of Spain, our group found 2.49 new cases/year (EBMT 2016). In Sweden, an incidence of 2.35 new cases/year has been recently reported (Vaht, Haematologica 2017). Our aim was to know the incidence and epidemiology of AA in a well-defined population.

Methods: In an ambispective study (IMAS), 7 general hospitals from 7 provinces situated in different geographical regions, that take care of a population of around 3.91 million inhabitants, participated in this study. All the patients diagnosed with AA were included. Data bases of the Hematology, Pathology, and Pharmacy Departments were used as a source of information.

Results: During the period 01/01/201031/07/2019, 103 new cases were identified (3-14 cases/year). The incidence of AA was 2.75 per million inhabitants per year. The median age at diagnosis was 56 years old (11-85), and gender was distributed almost equally between females and males. More than half of the cases were severe or very severe, and 9 out of 10 of the patients had transfusion needs. The most frequently employed approach at first line was immunosuppressive therapy with ATG/cyclosporine A (CsA). HSCT was a very infrequent 1st line therapy. At 1 year, two-thirds of the patients were in response (partial or complete). With a median follow-up of 6 years, threequarters of the patients were alive. See table.

N = 103
Period01/01/2010-31/07/2019
Age (years) (median; range)56 (11-85)
Gender (female/male)52.8% / 47.3%
Severity of the disease (very severe and severe/moderate)57.3% / 42.7%
Transfusion needs (yes/no)90.3% / 9.7%
First line treatmentATG/CsA: 52.4%; Allo-HSCT: 1.9%; Others: 45.7%
RR at day + 9050.6% (45.4% PR / 5.2% CR)
RR at day + 18053.3% (44.0% PR / 9.3% CR)
RR at day + 36561.3% (46.8% PR / 14.5% CR)
Survival at last visit75.3%
Follow-up (months) (median; range)60 (5-115)

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[Table. Description of the series]

Conclusions: 1) Worldwide, there are few studies focus on the epidemiology and management of AA patients. Particularly, this is the first national study of these characteristics ever performed in Spain; 2) We found an incidence of AA of 2.75 new cases/year; 3) No differences in gender were found; 4) ATG/CsA was the most frequently employed first-line therapy; 5) Long term response rate we found are similar to those shown in previous international reports of AA patients, and clearly show that there is an important room for improvement with new therapeutic approaches.

Disclosure: Nothing to declare.

P046 Allogeneic Stem Cell Transplantation from Alternative Donors for Children with Aplastic Anemia

Atsushi Narita, Hideki Muramatsu, Masayuki Imaya, Ayako Yamamori, Taro Yoshida, Manabu Wakamatsu, Shunsuke Miwata, Koutaro Narita, Hironobu Kitazawa, Rieko Taniguchi, Motoharu Hamada, Daisuke Ichikawa, Eri Nishikawa, Nozomu Kawashima, Yusuke Okuno, Nobuhiro Nishio, Seiji Kojima, Yoshiyuki Takahashi

Nagoya University, Nagoya, Japan

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for children with severe aplastic anemia (AA). With the improvement in HLA typing resolution and advancement of supportive care for graft-versus-host disease (GVHD), various donor options are available for patients without HLA-matched sibling donors, such as unrelated donors, HLA-mismatched family (haploidentical) donors, and cord blood (CB). This retrospective study aimed to evaluate the HSCT outcomes from these donors.

Methods: Treatment outcomes of 65 children with AA (aged < 20 years) who underwent HSCT between 1991 and 2018 in our institute were analyzed. Unrelated donors were matched to patients at the allele level of HLA-A, HLA-B, HLA-C, and DRB1. Patients were divided into three groups: serologically matched or one-locus mismatched related donors (MRD/1MMRD, n = 37), 8/8-matched unrelated donors (MUD, n = 9), and alternative donors (AD, n = 19). AD was further divided into 7/8-matched unrelated donors (7/8MMUD, n = 9), serologically 2-3 mismatched related donors (Haplo, n = 6), and CB (n = 4). Treatment failure was defined as death from all causes, graft failure, and second malignancy.

Results: The median age at HSCT was 11.2 (range, 1.3-18.8) years. The median follow-up period was 69 (range, 1-196) months. Differences were found in the median follow-up according to the donor source, which was longer in MRD/1MMRD and AD, 93 and 45 months, respectively, and shorter in MUD, 18 months (P < 0.001). The median time from diagnosis to HSCT was 9 (range, 0-135), 11 (2-78), and 11 (0-69) months for MRD/1MMRD, MUD, and AD groups, respectively (P = 0.627). Neutrophil engraftment was achieved after HSCT in all patients. The median day of neutrophil recovery was day+18 (range, +11 to +36). Two patients experienced second graft failure, and all of them were in the AD group (Haplo, n = 1; 7/8MMUD, n = 1). Cumulative incidences of grade II-IV acute GVHD were 5% (95% confidence interval [CI], 0%-12%), 0%, and 21% (95% CI, 0%-37%) for MRD/1MMRD, MUD, and AD, respectively (P = 0.092). The 3-year cumulative incidences of chronic GVHD were 8% (95% CI, 0%-17%), 30% (95% CI, 0%-58%), and 16% (95% CI, 0%-32%) for MRD/1MMRD, MUD, and AD, respectively (P = 0.241). The 5-year overall survival was not significantly different among the three groups (MRD/1MMRD, 97% [95% CI, 82%-100%]; MUD, 88% [95% CI, 39%-98%]; AD, 100%; P = 0.266). The cause of death was infections without graft failure in two patients (MRD/1MMRD, n = 1; MUD, n = 1). Failure-free survival (FFS) was tended to be lower in the AD group (MRD/1MMRD, 97% [95% CI, 82%-100%]; MUD, 88% [95% CI, 39%-98%]; AD, 79% [95% CI, 53%-92%]; P = 0.082).

Conclusions: The overall survival rate of HSCT from both MUD and AD in children with AA is comparable to those from MRD/1MMRD. However, the algorithm for donor selection should be considered according to FFS. Further study with a larger number of patients is needed to determine the preferable AD.

Disclosure: The authors declare. no conflict of interest.

P047 Outcome of Pediatric Acquired Aplastic Anemia: Single Center Experience

Elaf Al nasser, Ibraheem Abosoudah, Naif Aljohani, Hassan Altrabolsi, Ali Alharbi, Mohamed Bayoumy

King Faisal Specialist Hospital & Research Center, Jeddah, Saudi Arabia

Background: Severe Aplastic Anemia (SAA) is a rare hematological disease characterized by pancytopenia and a hypo cellular bone marrow in the absence of abnormal infiltrates. Allogeneic hematopoietic stem cell transplantation (HSCT) is the current available curative treatment, however for patients who lack matched sibling donor (MSDs), immunosuppressive therapy (IST) is widely accepted as an alternative first-line treatment. Outcome data of children with acquired aplastic anemia (AA) are lacking from our region.

Methods: Laboratory and clinical information of all children < 18 years of age with acquired SAA diagnosed between January 2005 and December 2015 at KFSH&RC were retrospectively collected. Relevant details about treatment given i.e. IST and HSCT, treatment outcome, overall survival (OS) and event free survival (EFS) were also recoded. An events were defined as death, treatment failure, or rejection.

Results: Thirty children were included in the study. Fifteen (50.0%) patients were female and 18 (60.0%) patients underwent matched family donor (MFD) HSCT while the remaining patients received upfront IST. Three-year OS and EFS for children undergoing upfront MFD HSCT was 100%. Out of twelve children treated with IST, three were evaluable for response. Two children died before receiving a rescue transplant. Seven of the patients failed upfront IST and received rescue transplants, of these two children died with infection and rejection. The OS of the patients who received rescue after failed IST was 70% and there EFS was 71%. The overall response to IST was seen in three out of twelve (25%) patients with two patients achieving complete response while one patient had a partial response. The 3-year estimated OS and EFS for children treated with IST was 66.6% and 15% respectively.

Conclusions: We observed an inferior outcome in patients who received immunotherapy in our study comparison to published international literature. This could be explained by higher prevalence of consanguineous marriages in the Saudi population and their genetic background. Alternative transplant modalities should be considered for those who lack matched family donor.

Disclosure: no conflict of interest

P048 Impact of CD34+-Stem Cell Boost on Outcome and Hematological Reconstitution in Patients with Severe Aplastic Anemia after Allogeneic Stem Cell Transplantation - A Retrospective Study

Rashit Bogdanov, Mareike Gocht, Amin Turki, Markus Ditschkowski, Dietrich W. Beelen

University Hospital Essen, Essen, Germany

Background: Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is still the standard treatment for acquired severe aplastic anemia (SAA) in patients younger than 40 years with sibling donors. Sufficient and durable reconstitution of haematopoietic donor stem cells is important for successful allo-HSCT. Poor graft function (PGF) after allo-HSCT is characterized by persistent pancytopenia, immunodeficiency and dependence on blood transfusions, despite of a complete donor chimerism. The probability of developing PGF seems to be increased in the absence of a regulatory bone marrow stromal microenvironment, even in cases where bone marrow is used as a source of stem cells.

Aim: To evaluate in a single-center retrospective analysis the long-term transplant outcome considering haematological recovery and overall survival (OS) in patients (pts) with SAA after allo-HSCT requiring CD34+-selected stem cell boosts.

Methods: The analysis comprises data of 35 pts with aplastic anemia after allo-HSCT from HLA-matched sibling (n=14) or unrelated (n= 21) donors, who underwent allo-HSCT between 2006 and 2018. The median age of the 26 male and 9 female pts was 28 years (range, 17 to 66). A myeloablative conditioning regimen was used in 6 pts, while 29 pts were treated with a reduced intensity immunosuppressive conditioning regimen. Bone marrow (n=20) or peripheral blood stem cells (n=15) with a median of 3.89 x 106 CD34+ cells/kg bodyweight (BW) (range, 1.4 to 14.6) were transplanted. PGF was diagnosed in 16 pts with a median of 46 days (range, 40 to 106) after allo-HSCT by bone marrow biopsy. The stem cell boost was performed using immunomagnetically selected CD34+ stem cells from original donors. The boost stem cell dose was 6.1 x 106 CD34+ cells/kg BW (range, 0.95 to 13.25). Statistical analysis was performed on with SAS 9.4 using the method of Fine and Gray for competing risk cumulative incidences and Kaplan Meier estimates for overall survival.

Results: The rate of complete hematological engraftment was 94% (33 of 35 pts), including 16 pts with CD34+-selected stem cell boosts infusion for poor graft function performed. The median time to recovery was 34 days (range, 16-100) for neutrophils and 62 days (range, 11-175) for platelets. The current 10-year survival rate is 80%. (without boost - 89.5%, with boost - 68,7%, p=0.03). No relapse of SAA developed. Seven (20%) pts died as a result of infectious complications (n=6), hemolytic uremic syndrome (n=1).

Hematological reconstitution in patients with or without CD34+ stem cell boosts - is presented in table 1.

Conclusions: The use of CD34+-selected peripheral blood stem cell boosts from the original donor allows a complete, albeit delayed regeneration of haematopoiesis in the majority of aplastic anemia patients with PGF after allo-HSCT. The leading causes of deaths were severe infectious complications due to prolonged cytopenia after allo-HSCT in this patient subset.

The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (9)

[Table 1. Hematological reconstitution after allo-HSCT in patients with SAA]

Disclosure: Bogdanov: Neovii Biotech, Jazz Pharmaceuticals, MSD.: Other: Travel subsidies. Beelen: Medac GmbH Wedel Germany: Consultancy, Honoraria. Turki: Jazz Pharmaceuticals, CSL Behring, MSD.: Consultancy; Neovii Biotech, all outside the submitted work: Other: Travel subsidies.

P049 Hematopoietic Stem Cell Transplant in Adults with Acquired Severe Aplastic Anemia

Gilbert Wilfred, Sen Mui Tan, Tee-Chuan Ong, SH. Shahnaz Syed Abd Kadir, Kim Wah Ho, Boon Liaw Kian, Jameela Sathar

Ampang Hospital, Ampang, Malaysia

Background: Hematopoietic stem cell transplant (HSCT) provides curative therapy in almost 90% of patients with severe aplastic anemia (SAA). Older age, long duration of disease with consequent heavy exposures to transfusion and active infection at the time of HSCT have a negative influence on outcome, favouring graft failure (GF) and graft versus host disease (GVHD). This study aimed to evaluate outcome of all SAA patient who received hematopoietic stem cell transplantation at a tertiary centre in Malaysia.

Methods: Data was obtained from transplant database and patients’ medical record at Ampang Hospital, Malaysia. Patients with acquired SAA who underwent HSCT between January 1999 until November 2019 were included. Demographics, clinical characteristics and treatment outcomes were collected and analyzed using descriptive statistics.

Results: A total of 84 cases were identified for this study with mean age of 23.7 ± 10.0 years. Fifty-eight percent of the cases were male (n=49). Malay ethnicity were the highest (51.8%) followed by Chinese (24.1%) and Native Sabah (14.4%). Majority were transplanted within 6 months of diagnosis (n=58, 69%) and out of this number, 20% received transplantation within six weeks. Forty-five cases (53.6%) used peripheral blood as stem cell source, 36 cases (42.%) used bone marrow and three cases (3.5%) used both. Most of the patients (60.7%) received non-Fludarabine based, Cy (cyclophosphamide)-ATG (anti thymocyte globulin) as their conditioning regime. Mean engraftment for neutrophil was 14.9 (range 6 - 29) days and 15.1 (range 8 - 35) days for platelet. Patients who underwent peripheral blood stem cell transplant had significant early engraftment for neutrophil (p < 0.01) in comparison to bone marrow. However, this finding is not observed with platelet engraftment. Twenty-nine cases (34.5%) died within 100 days of transplant from treatment-related complications (n=23), disease progression (n=4) and others (n=2). Four of the transplanted patients required second allogeneic transplant due to secondary graft failure, however only one survived.

Conclusions: This study shows that only small percentage of cases were transplanted less than six weeks from diagnosis. Early transplant strategy is necessary to improve outcome among patients with SAA. Further study is required to look into the factors leading to delay in diagnosis and treatment among them.

Disclosure: Nothing to declare.

P050 Hematopoetic Stem Cell Transplant in Fanconi Anemia using Matched Related and Haploidentical Donors- A Single Centre Experience

Ajeitha Loganathan, Pooja Mallya, Prathip Kumar, Shobha Badiger, K S Nataraj, Sharat Damodar, P K Vasundhara, Arun Danewa, Mohammed Salmaan, Mohana Reddy, Sunil Bhat

Mazumdar Shaw Medical Center, Narayana Health City, Bengaluru, India

Background: Hematopoetic stem cell transplant (HSCT) is the only curative option for progressive marrow failure in Fanconi Anemia (FA). There is paucity of data on HSCT for FA from India, especially using haploidentical donors. We report our experience of allogeneic transplants for FA.

Methods: We retrospectively analyzed the records of 13 children who underwent 15 HSCTs from 2014 to 2019.

Results: A total of 13 children underwent 15 HSCTs. The median age was 92 months (27-235). The donors were: Haploidentical donor (n=6), HLA matched siblings (n=5) and HLA matched related donor (n=2). Graft source: Bone Marrow (n=7); PBSC (Peripheral blood stem cells) (n=-8). Among haploidentical transplants, the graft source was T-cell depleted (TCD) PBSC in five and T-Cell replete (TCR) in one. The depletion method was TCR alpha/beta with CD19 + cell depletion using CliniMacs system. Conditioning regimen: Fludarabine/Cyclophosphamide (total dose of 40 mg/kg) and ATG in 14 (along with TBI in one), Treosulphan-Flu-Cy-ATG in one and Fludarabine-Busulfan-ATG in one. GvHD prophylaxis: Cyclosporine & Mycophenolate Mofetil in MSD/MRD HSCTs, Sirolimus in Haploidentical HSCTs with TCD grafts and Post-transplant cyclophosphamide (25mg per kg for 2 days), CSA and MMF in Haploidentical HSCT with TCR graft. The median infused CD34+ cell count was 7.8 × 106/kg (range 3.42-21.5× 106/kg). Of the 13 patients who underwent transplant, 10 engrafted with a median neutrophil and platelet engraftment at day 11 and 12 respectively. Three did not engraft (2-Haplo with TCD PBSC, 1-MRD with Marrow) -of which two engrafted after second transplant, one child had donor specific antibodies and expired secondary to infection. All the four who had acute GvHD received TCR stem cells (3-marrow, 1-TCR PBSC from haploidentical donor). Four patients had chronic GvHD (all were matched sibling/related, 3-Marrow, 1-PBSC) of whom one expired from severe bronchiolitis obliterans and the rest are alive with moderate skin GvHD. Interestingly, none of the patients who received TCD PBSC developed either acute/chronic GvHD. All alive patients developed full donor chimerism and are disease free. One achieved full donor chimerism after donor lymphocyte infusions for mixed chimerism. Day 100 survival rate was 76.9%. (10/13). OS: For entire cohort - 69.2 %, for haploidentical HSCT cohort -66.7% (4/6) at a median follow up of 211 days.

Mean follow up (days)211 (30-570)
Neutrophil engraftment (in days)11 (9-13)
Platelet engraftment (in days)12 (8-18)
Acute GvHD Grade III-IV4/13 (30.7%) 3/13
Chronic GvHD4/10 (3-alive, 1-expired)
Primary graft failure3/15 transplants, 2 underwent retransplant and alive, 1 expired
Expired4
Cause of deathRejection/Infection-2, GVHD-2
Chimerism11/11 full donor chimerism, One achieved after four DLI
OS69.2%

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[Allogenic transplant outcomes in Fanconi Anemia (N=13, Number of transplants=15)]

Conclusions: HSCT for FA has good outcomes with reduced intensity conditioning regimens. Haploidentical donors are alternatives in the absence of matched donors with reasonably good outcomes and minimal GVHD rates using TCD stem cell source.

Disclosure: Nothing to declare.

P051 Hematopoietic Stem Cell Transplantation for Pediatric Severe Aplastic Anemia: Results of a Single Center

Gulen Tuysuz Kintrup, Hilal Akbas, Funda Tayfun Kupesiz, Ayse Nur Akinel, Cigdem Sivrice, Serife Kaya, Elif Guler, Alphan Kupesiz

Akdeniz University, Antalya, Turkey

Background: Aplastic anemia (AA) is a life-threatening form of bone marrow failure characterized by pancytopenia and hypo cellular marrow. The pathogenesis of the disease is thought to involve autoimmune process and it is associated with very high mortality if left untreated. Allogenic hematopoietic stem cell transplantation from a HLA-MRD is the preferred treatment in children and young adults. But when MRD is not available immunosuppressive therapy with CsA and ATGAM or transplantation from an alternative donor are the therapeutic options.

Methods: We retrospectively analyzed the data of AA patients who underwent HSCT at Pediatric Stem Cell Transplantation Unit of Akdeniz University Hospital from January 2000 to December 2017.

Results: A total of 31 HSCT was conducted over 28 patients during this period. There were 19 boys and 9 girls with a median age of 10 years (range: 3.4-19.8) at transplantation. Eighteen patients have previously received immunosuppressive agents but were unresponsive to the treatment. Ten patients were receiving regular blood products before transplantation. The source of HSCT was PBSC in 16 and BM in the rest 15 transplantations. Patients received HSCT as graft from a matched unrelated donor (n:15), from a matched sibling donor (n:10), from a matched family donor (n:5), and from a haploidentical donor (n:1). All patients received FLU or CY based reduced intensity conditioning regimens and GVHD prophylaxis comprised a calcineurin inhibitor plus methotraxate in 90% of patients. The median infused CD34+ cell dose was 4.9 ×106/kg (range:1.2-18.2×106/kg). Within a median follow up of 55 months (range: 2-206) after transplantation, 5-year overall survival was 78% in the total group and there was no statistical significant difference between the MRD and MUD groups (92% vs. 53% p=0.13). Grade III-IV aGVHD occurred after 3 of the transplantations (10%). Six patients died at a median of 9 months (range: 2-88) after transplantation.

Conclusions: Our results show that HSCT for AA patients has promising results and transplantation from unrelated donors are approaching those of MRD transplants. Application of immunosuppressive drugs, treatment rabbit ATG instead of ATGAM in previous years, and delay of transplantation waiting for appropriate donor might be the reasons for poor survival in MRD group.

Disclosure: Nothing to declare.

P052 Immunosupressive Therapy in Peadiatric Aplastic Anemia, Single Centre Experience

Wafaa Ezzat Ibrahim mohamed Abou Sayed Ahmed, Safa Matboly

Ain Shams University, Cairo, Egypt

Background: Aplastic anemia (AA) is life threatening disorder in pediatric age group with increasing incidence nowadays, with hematopoietic stem cell transplant being the 1st line therapy; immunosuppressive therapy (IST) is the alternative therapy and is the most commonly used modality of treatment especially. in the developing countries

Methods: We aimed to assess the outcome of IST in children with AA. Data for 25 children treated with IST from January 2014 to January 2019 (5 years) were retrieved from clinic records. IST included rabbit anti thymocyte globulin (ATG) along with cyclosporine A and another group were treated by sand immune alone

Results: Patient characteristics include median age (9) with 73 %male and 26.1 %female. with median interval between diagnosis and start of IST(0.5 -1) and around 30.4 % with hepatitis A associated aplastic anemia. Complete response, partial response and nonresponse was seen in 4 (37.5) (0%) and 1(12.5%) patients, respectively in patients received ATG and sandimune. while in patients received sandimune alone complete response and no response was seen in 7(46.7Z%) and 8 (53.3%) respectively. The median time to best response in the whole cohort was 12 months. There was no difference in outcome related to severity of AA, or higher ALC. There was a significantly better rate of response (p value: .03) in both groups of patients with higher Hb level, HCT, and PLT level before start of IST. An overall response rate in both groups around of 39.5% reported a 5-year OS of 50% with 16% of patients with complete response with HAAA. A delayed time to complete response with prolonged requirement of cyclosporine therapy was detected

Conclusions: In a developing country setting, IST with ATG and cyclosporine seems to be an alternative treatment for aplastic anemia in children lacking MRD.

Clinical Trial Registry: not applicable

Disclosure: Nothing to declare.

P053 Cyclosporine, Danazol and Romiplostim in Severe Aplastic Anemia in Prettansplant Period: Retrospective Analysis of Five Cases

Nilesh Wasekar, Girish Badarkhe, Sudarshan Pandit, Raj Nagarkar

HCG Manavata Hospital Nashik, Nashik, India

Background: Treatment of Aplastic anemia mainly consist of ATG+CSA or Hematopoietic stem cell transplantation. Due to financial constraints majority of patients cannot opt for these available treatment options. The patients who arrange the cost of HSCT, needs supportive care until the definitive treatment (transplant or ATG) is done. The cost of SDP and PCV and antibiotics for infection is a major hurdle to arrange the funds for BMT. To reduce that, we have used combination of CSA, Danazol and Romiplastim as a bridge to BMT in our five patients of Aplastic anemia.

Methods: A retrospective study in a cohort of patients with AA. The study was conducted from January 2018 to December 2019. Romiplostim (5ug/kg) SC once a week was used for 4-8 weeks. Cyclosporine 5mg/kg per day was used to keep level between 150-200. Danazol was used 100 mg TDS, dose was increased upto 600 mg/day after monitoring liver function test.

Results: Five patients with a mean age of 47 (18-83) years were included in the study. Four patients achieved some form of remission (partial/complete), one patient died, one patient is in complete remission, and one underwent HSCT successfully. Two patients are in partial remission waiting for the HSCT.

Conclusions: Improved response rates with triple therapy was observed in patients with severe AA. The triple therapy can be used as a bridge for definitive treatment in Aplastic Anemia.

Disclosure: None

Autoimmune diseases

P054 The long-term Safety and Efficacy of Autologous Haematopoietic Stem Cell Transplantation for relapsing-remitting Multiple Sclerosis Indirectly Compared to Alemtuzumab: A Systematic Review

Owain Greaves1, Amit Patel1,2

1University of Liverpool, Liverpool, United Kingdom, 2The Christie NHS Foundation Trust, Manchester, United Kingdom

Background: Multiple Sclerosis (MS) is a chronic, progressive, central neurological disease mediated by autoimmunity. Despite availability of anti-inflammatory drugs such as alemtuzumab, disease progression still occurs with minimal initial reversal of symptoms. Autologous haematopoietic stem cell transplantations (aHSCT) for treatment of MS has seen more dramatic reversal in symptoms but have not been previously directly compared to alemtuzumab.

Methods: Systemic review of cohort studies and randomised control trials (RCTs) of Relapsing Remitting MS (RRMS) patients treated with alemtuzumab or aHSCT.

Results: aHSCT.

A total of 144 studies met the search criteria. After application of eligibility criteria and removal of duplicate data, six studies including 277 patients with RRMS, who failed initial DMTs, were included in the review. All patients were initially alemtuzumab naïve. Mean baseline EDSS was 1.5-6.3. Three studies used myelo- and lympho-ablative BEAM-ATG conditioning; the others used lympho-ablative cyclophosphamide (50mg/kg/day for 3-5 days) with ATG (or alemtuzumab in a minority of patients). Both rabbit and horse ATG were used with dosing between 2.5-10mg/kg/day for 2 days or 0.5-1.5mg/kg/day for 5 days.

The available data showed a mean EDSS reduction from a baseline of 3.89 (3sf) to 2.96 at five-year follow-up.

Studies with lower pre-aHSCT EDSS experienced the greatest reduction in EDSS. Event-free survival (EFS) to five years was variable between studies ranging from 0% if high pre-aHSCT EDSS, to 85% if low EDSS pre-aHSCT. Studies with the lowest initial EDSS experienced higher progression-free survival (PFS) to five years, around 90%.

All-cause mortality across the studies was 2.6%; treatment related mortality (TRM) was 0.7%.

The percentage of patients retained in the studies after five years stood at only 28.9% compared to the alemtuzumab arm where retention stood at 83.0% (p< 0.001). Comparison of EDSS at five-year follow-up between the two study arms may therefore be misleading due to survivorship bias in the aHSCT arm.

Alemtuzumab.

A total of 39 studies met the search criteria. After application of eligibility criteria and removal of duplicate data, three studies included 759 patients treated with alemtuzumab: CAM MS223, CARE-MSII, and CARE-MSI, were used in the study. Both CAM MS223 and CARE-MSI included treatment naïve patients; CARE-MSII (357 patients) included previously DMT exposed patients.

Mean EDSS pre-alemtuzumab was 1.9-2.7; only 6 patients had an EDSS >5.0. Peak post-alemtuzumab EDSS reduction occurred at 2 years with the CAM MS223 study; the best mean EDSS reduction was 0.3. The improvements at two years were negated by five years.

Mean EDSS across the studies progressed from a baseline of 2.31 (3sf) to 2.34 at five-year follow-up representing a mean increase of 0.03.

All-cause mortality across studies was 0.5%; TRM was 0.1%.

Conclusions: While it is imperfect to indirectly compare treatments from different studies, EDSS outcome patterns between aHSCT and alemtuzumab differed remarkably. aHSCT, in contrast to alemtuzumab, was associated with the largest magnitude of fall in EDSS that was sustained in the long-term to five years. A direct comparison of aHSCT with alemtuzumab in a RCT seems warranted to confirm these observations of long-term benefit with aHSCT.

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[Mean change in EDSS post-HSCT or alemtuzumab]

Disclosure: Nothing to declare.

P055 Reconstitution of Natural or vaccination-driven Immunity after aHSCT in Multiple Sclerosis

Chiara Innocenti, Elio Ingenito, Maria Pia Amato, Alessandro Barilaro, Gaetano Bianchini, Teresa Capobianco, Maria Antonia Calia, Romina Ceschini, Arianna Fani, Marta Giannini, Antonella Gozzini, Stefano Guidi, Alice Mariottini, Luca Massacesi, Francesca Materozzi, Chiara Nozzoli, Anna Maria Repice, Gian Maria Rossolini, Serena Urbani, Riccardo Saccardi

Careggi University Hospital, Florence, Italy

Background: In the last 20 years, high dose chemotherapy with autologous hematopoietic stem cell transplantation (aHSCT) has emerged as an effective and safe treatment for aggressive forms of multiple sclerosis (MS). Nevertheless, no data have been published about reconstitution of either natural or vaccination-driven immunity after aHSCT and the consequent indication to re-vaccinate patients. We report an updated analysis of antigen-specific immune recovery in a series of MS patients after aHSCT, having increased the subset of patients included in the study.

Methods: Blood samples from 32 MS patients who underwent aHSCT in our Center between 2006 and 2017 were analyzed. Each patient underwent mobilization with cyclophosphamide (CTX) 4gr/sqm + GCS- F and was conditioned with BEAM/ATG regimen. Antibody titres for varicella-zoster, measles, rubella, and hepatitis B viruses were analysed before mobilization (baseline) and at 6 months, 1 year and then yearly after aHSCT. Chemiluminescent Microparticle Immunoassays (CMIA) were performed to determine Rubella and hepatitis B surface antigen antibodies (anti-HBsAg). Chemiluminescent Immunoassays (CLIA) were performed to assess Varicella Zoster and Measles. All patients received prophylaxis with acyclovir and Thrimethoprim-Sulphametoxazole for six months after aHSCT. Patients did not receive any re-vaccinations in the follow-up period.

Results: All patients showed a complete and sustained engraftment: median (range) time to PMN≥0.5x109/L and platelets≥20x109/L were 12(9-15) and 11(7-14) days, respectively. Patients showed also a complete return to a normal lymphocyte subset counts within two years from transplant. No case of measles, rubella, or chickenpox occurred after transplant, with a median follow-up of 40 (17-124) months. Table 1 reports the number of patients with positive or negative antibodies titres at baseline, 6 months and 2 years after aHSCT, respectively. A loss of serum protective immunity was observed in a variable rate of patients with all the tested agents: 14% in measles, 16% in rubella, 20% in hepatitis B, and 7% in Varicella Zoster.

Conclusions: Re-vaccination in patients who underwent an autologous HSCT for a severe autoimmune disease is a common practice in many centers and is also recommended in the EBMT guidelines. However, some concerns about this practice were raised for the putative role of vaccinations as an autoimmunity trigger. In the literature there is no study on the loss of protective antibody titer in either natural or vaccination-driven immunity with regards to patients transplanted for autoimmune diseases. In our series a high variability in antibodies titers at baseline was shown. The larger subset analysed confirms that most patients showing a protective titre against the tested agents, show a trend to maintaining it. A possible approach might be to revaccinate the patients with unprotective titre at 2 years after HSCT, taking into account the individual risk of being exposed to the infection; a larger series of data is necessary to provide conclusive evidences on this topic.

Disclosure: No disclosures

P056 High-dose Immunodepletion with Autologous Stem Cell Rescue for Treatment of Aggressive Multiple Sclerosis

Antonia Mueller, Ilijas Jelcic, Panos Stathopoulos, Nathan Wolfensberger, Katharina Ritter, Urs Schanz, Roland Martin

University Hospital Zurich, Zurich, Switzerland

Background: Multiple sclerosis (MS) is the most common chronic inflammatory demyelinating disease of the CNS and the leading cause of non-traumatic neurological disability of young adults. Inflammatory forms of MS respond to immunomodulation with disease modifying treatments (DMTs), but some subgroups of patients continue to have clinical and/or MRI disease activity despite DMTs. There is increasing evidence, including randomized controlled trials, that demonstrates robust clinical efficacy of high-dose chemotherapy (HDCTx) with autologous stem cell rescue (ASCT) in patients with highly active MS.

Methods: In 07/2018 the Swiss Federal Office of Public Health approved the treatment of MS patients with HDCTx+ASCT at our single center (University Hospital Zurich). To be eligible for reimbursement (i) patients must have inflammatory breakthrough activity of MS despite highly effective DMT; (ii) the indication needs to be confirmed by our interdisciplinary hemato-neuroimmunological board; (iii) patients are required to participate in a registry study for 5 years post-ASCT. Patients are mobilized with 2 days of cyclophosphamide 2g/m2 and Filgrastim. HDCTx comprises BEAM (BCNU, etoposide, cytarabine, melphalan) and ATG 3.75 mg/kg on d+1 and +2 post stem cell infusion.

Results: So far 20 patients (10 females, 10 males) with a mean age of 40.6 years (+7.5y) and disease duration of 8.4 years (+4.4y) were enrolled into the registry. On the “Expanded Disability Status Scale” (EDSS) patients had a mean score of 5.0 (+1.2). 6/20 (30%) patients had relapsing remitting MS (RRMS), 7/20 (35%) had secondary progressive (SPMS) and primary progressive (PPMS) disease, respectively. The indication for HDCTx+ASCT was clinical progression in 14/20 patients (70%), clinical disease activity in the form of relapses in 5 (25%), and/or radiological activity (new or contrast-enhancing lesions) in 7 patients (35%). Last treatments prior to ASCT were fingolimod (15%), rituximab (40%), ocrelizumab (30%), or natalizumab (15%).

Overall, treatment was tolerated well, although the majority of patients developed adverse events (AE). Most common AEs were oral mucositis/pharyngitis and/or enteritis in 18/20 patients. Upper airway and urinary tract infections were each observed in 4 patients, respectively. CMV reactivations occurred in 4/20 patients and were severe in 2 (including CMV enteritis and hospitalization for intravenous antiviral therapy). HSV reactivations (n=2) and BK cystitis (n=2) were also observed. A total of 9 serious AEs were recorded (CMV n=2; hemorrhagic cystitis, gastroenteritis with ileus, laryngitis, cervical abscess (post mobilization, prior to ASCT), pulmonary embolus (several months post ASCT), gastrointestinal bleeding, manic episode). Six patients experienced transient neurological deterioration. Other AEs were hypotension (n=3), cholecystolithiasis (n=1), and epistaxis (n=1). With the limitation of short follow-up, a substantial proportion of patients reported improvements of neurological functions and less fatigue, however, longer observation periods are needed to evaluate the potential benefits of this intensive treatment.

Conclusions: Here, we report on the establishment of a national registry program for MS patients undergoing ASCT. The fast recruitment indicates an unmet need for a subgroup of young patients with aggressive, conventional DMT-refractory MS. The safety profile is acceptable from a transplanter’s perspective - however, bacterial and viral infections are common and require particular attention and prophylactic care.

Clinical Trial Registry: BASEC-number: 2018-01854 (Data and Biomaterial Collection for the Evaluation of Autologous Hematopoietic Stem Cell Transplantation in Relapsing Remitting and Progressive Multiple Sclerosis Patients (Registry))

Disclosure: Nothing to declare.

P057 Hematopoietic Stem Cell Transplantation does not Change the Expression of Endothelial Markers in Skin Biopsies of Systemic Sclerosis Patients

Maynara Santana, Djulio Zanin, Deisy Silva, Marianna Vasconcelos, Daniela Moraes, Juliana Dias, Vanessa Leopoldo, Marília Oliveria, Álvaro Henrique-Neto, Kelen Farias, Leandra Ramalho, Maria Carolina Oliveira

University of São Paulo, Ribeirão Preto, Brazil

Background: Systemic sclerosis (SSc) is an autoimmune disease characterized by vascular damage, deregulation of the immune system and fibrosis of the skin and internal organs. The injury and apoptosis of microvascular endothelial cells are indicated as initial events of the disease, leading to physiological changes in the endothelium and vasculopathy. Autologous Hematopoietic Stem Cell Transplantation (AHSCT) promotes resetting of the immune system and has emerged as a treatment option for patients with severe and progressive SSc. Although AHSCT leads to clinical improvement, the mechanistic effects are still not completely understood. In this study, we aimed to investigate if AHSCT modifies the expression of endothelial markers in skin biopsies.

Methods: Samples of skin from the forearms of 27 SSc patients were evaluated by immunohistochemistry (IHC) before and at 6 and 12 months after AHSCT. Biopsies were marked with anti-CD31, -VEGF, -VEGFR2, -ANGIOPOIETIN 1, -ANGIOPOIETIN 2, -TIE, -ENDOTHELIN-1, -CD105 and -VE-CADHERIN antibodies and stained with Hematoxylin and Eosin (HE) and Picrosirius Red. The images were analyzed by ImageJ software

Results: Most participants were female (78%) with a mean (standard deviation, SD) age of 36 (9.4) years. The mean (SD) time between diagnosis of disease and transplantation was 3.2 (3.1) years. Clinical evaluation of fibrosis assessed by Rodnan´s score improved at 6 and 12 months compared to baseline (p< 0.0001). Histological analysis of fibrosis evaluated by HE and picrosirius red showed reduction of skin thickness (p< 0.0001) and collagen density (p=0.0193) after AHSCT.

The only endothelial marker that decreased after AHSCT was ANG1 (p=0.0001). All the other evaluated markers did not change (p>0.05) after AHSCT, when compared to baseline. Except for ANG1, our results indicate that ASHCT does not modify the expression of endothelial markers, anti-CD31, -VEGF, -VEGFR2, -ANGIOPOIETIN 1, -ANGIOPOIETIN 2, -TIE, -ENDOTHELIN-1, -CD105 and -VE-CADHERIN.

Conclusions: Our study shows that AHSCT therapy is able to improve fibrosis by reducing skin thickness and collagen fiber density, as assessed by Rodnan’s score and by histopathological analysis, respectively. However, no changes in markers of endothelial damage were detected, except for ANG1, which is related to vessel stabilization. Our data suggest that AHSCT may affect disease pathogenesis differently, concerning fibrosis and vasculopathy. Our results suggest that AHSCT does not improve SSc-associated endothelial damage, indicating that additional therapies may be warranted to more effectively treat the endothelial injury. The decrease in Rodnan´s score may be more associated with improvement of fibrosis than to a beneficial effect on the microvascular compartment.

Disclosure: Nothing to declare.

P058 Autologous Stem Cell Transplantation for Non Hematological Diseases. The Dutch Experience of MS Patients going Abroad

Ellen P.A. Kramer1, Bram Platel2, Frederike J.A.E Ambagtsheer3, Gerald G.J.D Hengstman4, Otto O Visser5

1Amsterdam UMC, Location VUmc, Amsterdam, Netherlands, 2Not Applicable, Manilla, Philippines, 3Erasmus MC, Rotterdam, Netherlands, 4Catharina Ziekenhuis, Eindhoven, Netherlands, 5Isala Ziekenhuis, Zwolle, Netherlands

Background: In the Netherlands, an unknown number of patients go abroad to fee for service clinics for stem cell transplantation for non-hematological diseases. In this IRB approved study, we gather information about patients that went abroad and how it affected their health care.

Methods: Patients going abroad for stem cell transplantation on their own initiative for any kind of disease were recruited through (social) media like Facebook communities and newspapers.

Patients were invited to contact the research team. To participants giving informed consent, a questionnaire was sent.

The survey consisted of 3 parts: one set of questions regarding the stem cell transplantation abroad. Additionally, two validated patient-reported outcomes were included: the EORTC30 and NeuroQoL54.

Results: To date out of 51 participating patients, 30 finished the survey. 91,4% underwent a stem cell transplantation for multiple sclerosis (MS), 2,9% for Lyme’s disease and 8,7% for other reasons

For the preliminary results presented here, we report on the first part of the questionnaire for 24 patients that had filled out the survey (before Dec. 2019) and received aHSCT treatment for MS.

A total of 24 people were included in this preliminary analysis (12 [50%] women; mean age, 46 [SD, 9.7]), 7 relapsing-remitting MS (RRMS, 7 secondary progressive MS (SPMS), 10 primary progressive MS (PPMS), (mean disease duration, 8 years [SD, 6.1], [Range 0-23]).

Most people were treated in Russia 10 [42%], Mexico 8 [33%], India 3 [13%]. The other three were treated elsewhere.

All except for one patient chose for their center based on “own research” or “success stories from other patients”. None of the patients were referred by their physician. In three cases, the participants were advised in their decision for a specific clinic by their neurologist.

None of the participants was treated as part of an RCT.

Thirteen participants arranged for follow-up visits with a hematologist, three were advised so by their neurologist. Five arranged these check-ups after their return. Six have not had any follow-up by GP or hematologist.

Sixteen participants did not feel supported by their treating physician in their decision.

The average cost was € 55000 [Range 27000-110000. Sixteen participants [67%] financed through crowdfunding. Others paid with their own means. In none of the cases, the health insurance contributed to financing the treatment. Aftercare was paid for by health insurance in 21 [87%] participants.

Conclusions: The decision to go abroad for HSCT for not supported indications is usually made by the patient, regardless of the advice of the treating physician. Many patients go abroad for SPMS and PPMS, whereas highly active RRMS is the only evidence-based indication. As a result, patients undergo high-risk treatment for non-evidence based indications (like progressive MS). Patients are easily lost to follow up, as they often arrange aftercare on their own. Central registration of people going abroad for this high-risk treatment could contribute to better safety with the ultimate goal to organize reimbursement for selected cases and attention to aftercare.

Clinical Trial Registry: Not applicable

Disclosure: nothing to declare.

P059 Analysis of Cost and Charges for non-myeloablative Hematopoietic Stem Cell Transplantation for Relapsing Remitting Multiple Sclerosis in the United States

Richard Burt, Kathleen Quigley, Indira Arnautovic, Xiaoqiang Han

Northwestern University, Chicago, IL, United States

Background: Multiple sclerosis (MS) afflicts 2.5 million people worldwide (400,000 in the United States), and is a chronic disease, second only to congestive heart failure in cost of health care for a chronic illness. Lifetime direct costs per patients are greater than 4 million dollars and disease modifying therapy (DMT) is approximately 75% of the direct costs. DMT cost $80,000.00 per year (with a few costing more). We reported that after hematopoietic stem cell transplantation (HSCT) for frequently relapsing MS, only 16% relapsed and needed to restart DMT after 5 years. We now evaluated cost/ charges for HSCT on 42 consecutive patients treated with a non-myeloablative cyclophosphamide (200 mg /kg) and rabbit antithymocyte (ATG) (6.0 mg/kg) regimen.

Methods: Peripheral blood stem cells were collected 10 days after intravenous cyclophosphamide (2 g/m2) and 5 to 10 µg/kg per day of subcutaneous filgrastim beginning 5 days after cyclophosphamide. The immune ablative regimen was intravenous cyclophosphamide, 50 mg/kg per day on days −5 to day −2 before stem cell infusion (day 0) and rabbit antithymocyte globulin, 0.5 mg/kg on day −5, 1.0 mg/kg on day −4, and 1.5 mg/kg on days −3, −2, and −1. Methylprednisolone (1000 mg) was infused 30 minutes prior to rabbit antithymocyte globulin infusion.

Charges included all tests including blood draws, MRI imaging, echocardiograms, electrocardiograms, and chest radiograph, and all treatments and interventions including pre-HSCT evaluation, hematopoietic stem cell mobilization and cryopreservation, inpatient transplant admission charges, and all medications, nursing care, and room charges. The only charges not captured were physician history and physical and physician progress notes. Analysis was separated into direct costs (costs directly related to patient care (e.g. medications, laboratory tests, transfusions, nursing care), indirect costs (cost necessary to operate a hospital but not directly related to patient care e.g. managers, supervisors, medical records, accounting, information systems, marketing, legal, malpractice insurance, building maintenance and depreciation, house-keeping), total cost (sum of direct and indirect), net revenue collected, and net income (profit).

Results: Mean direct costs were $42,295 (range $33, 887 to $57,704), mean indirect costs were $42,888 (range $33,653 to $62,555), and mean total costs were $85,184 (range ($70,635 to $120,260). Mean revenue collected was $95,268 (range $16,544 to $173,204) and mean net income (profit) per patient was $10,084.

Conclusions: The mean costs and charges of HSCT using this non-myeloablative regimen are equivalent to DMT charges for one year (approximately $80,000) but comparable DMT charges do not include physician, laboratory, imaging, or hospitalization fees, if any. Since after a one-time treatment with a non-myeloablative HSCT regimen, the majority of patients remain treatment-free beyond 5 years, non-myeloablative HSCT with a cyclophosphamide ATG regimen appears to be cost effective.

Clinical Trial Registry: None

Disclosure: Nothing to declare.

P060 Autologous Stem Cell Transplantation in Behçet´s Disease: A Retrospective Study

Mathieu Puyade1,2,3, Amit Patel4, Yeong Ler Lim5, Norbert Blank6, Manuela Badoglio7, Francesca Gualandi8, David Ma9,10,11, Natalia Maximova12, Tobias Alexander13, John Snowden14

1CHU de Poitiers, Poitiers, France, 2CHU de Poitiers, Poitiers, France, 3MATHEC, Hôpital Saint Louis, Paris, France, 4The Christie NHS Foundation Trust, Manchester, United Kingdom, 5University of Liverpool, Liverpool, United Kingdom, 6Heidelberg Hospital, Heidelberg, Germany, 7EBMT ADWP Office, Paris, France, 8IRCCS Ospedale Policlinico San Martino, Genova, Italy, 9St Vincents Hospital, Sydney, New South Wales, Sydney, Australia, 10University of New South Wales, Sydney, Australia, 11St Vincent’s Hospital, Darlinghurst, Sydney, Australia, 12IRCCS Burlo Garofolo, Trieste, Italy., Trieste, Italy, 13Charité - University Medicine Berlin, Berlin, Germany, 14Sheffield Teaching Hospitals NHS Foundation, Sheffield, United Kingdom

Background: Behcet´s disease (BD) is a rare autoimmune disease mostly presenting with recurrent oral and genital aphthous ulcers, and uveitis. Other common symptoms include gastrointestinal, vascular, neurological and articular manifestations1. Treatment is based on chronic immunosuppression with conventional disease modifying or targeted biologic drugs2, although some refractory patients have been treated by autologous hematopoietic stem cell transplantation (AHSCT)3. This study aims to evaluate the outcome of AHSCT in adult patients with BD.

Methods: Adults who received AHSCT primarily for BD (according to International Classification Criteria) were identified retrospectively within the EBMT registry. Treating physicians were surveyed to produce a retrospective evaluation of outcomes. Complete Remission (CR) was defined as no evidence of disease activity and Partial Remission (PR) was defined as any documented clinical and/or laboratory response in patients that is less than CR.

Results: We retrospectively collected the data from 8 out of 9 cases reported to the EBMT registry and extracted data of 2 further patients from published literature4. Four were female, median age at onset of BD was 24 years (range 9-50). Median age at AHSCT was 32 years (27-51). Patients had received median 4 (2-12) prior lines of therapy: 89 % of the patients were treated with corticosteroids, and 50 % received either methotrexate, antiTNFa or cyclophosphamide. All had active disease before mobilization, which was performed with cyclophosphamide and G-CSF in 9 patients and G-CSF alone in 1 patient. Conditioning regimen was Melphalan 200mg/m² in 5 patients, BEAM in 3 patients, and Cyclophosphamide 200mg/kg plus antithymocyte-globulin (ATG) in 2 patients. Median follow-up was 48 months (range 6-120 months). No TRM was reported, three patients had infectious complications and a single patient had paroxysmal atrial fibrillation, line-associated deep venous thrombosis and depression. At 6 months, 6 patients were in PR with corticosteroid maintenance and 3 in CR without any further treatment. There was one relapse with pan-uveitis. One patient failed to respond to AHSCT and proceeded to rescue with allogeneic HSCT, but died five years post-transplant from chronic GvHD and CMV infection. Otherwise, no late complications in patients treated with AHSCT were reported.

Conclusions: AHSCT is feasible and safe in multi-refractory patients with BD. Although treatment-free CR was achieved in only 3 of 10 patients analyzed, AHSCT has the potential to stabilize BD in patients who fail to respond to conventional therapies. Further evidence, ideally from prospective studies, are warranted to determine whether AHSCT should be considered a standard of care in treatment-resistant BD.

Disclosure: No disclosure

P061 Safety and Tolerability of Autologous Hematopoietic Stem Cell Transplant in Multiple Sclerosis: A Single Center Experience

Pawan Kumar Singh, Isha Gambhir, Ragesh Radhakrishnan Nair, Rohan Halder, Zahier Ahmad Shekib, Manish Mahajan, Sumit Singh

Artemis Hospital, Gurugram, India

Background: Multiple Sclerosis (MS) is an autoimmune disease in which there is both B and T cell mediated destruction of the nervous system. Historically it was observed that Autologous Hematopoietic Stem Cell Transplant (HSCT) is safe and effective in achieving long term Disease Modifying Therapy (DMT) free survival. Initially myeloablative conditioning with BEAM-ATG (BICNU, Etoposide, Ara-C, Melphalan - Anti Thymocyte Globulin) was used, but the mortality rates were high, so the non-myeloablative conditioning with Cyclophosphamide-ATG (Cy-ATG) was used, showing almost same outcome and with low mortality rates.

Methods: Seventy one consecutive patients of MS who underwent AHSCT were prospectively enrolled at a single center tertiary hospital.

Results: A total of 71 patients were of MS with median age 48 years (range 25-67 years) and a total of 65 patients underwent AHSCT out of which 36 (51%) males were included. Six patients were rejected due to various reasons. The diagnosis of MS was confirmed by clinical evaluation, MRI, VEP and BERA. Of these, 36(51%) were SPMS, 22 (31%) were RRMS and 13(18%) were PPMS with a median EDSS score of 5 (range 1 - 8.5). the median time from diagnosis to AHSCT was 11 years (range 0 - 37 years). In majority of these patients; 53(81%) stem cell mobilization was done with G-CSF and in remaining either Cyclophosphamide + G-CSF 11(17%) or G-CSF + Plerixafor 2(3%) was used. Regimen related toxicity was seen in 9 patients in the form of anaphylaxis (5), hemorrhagic cystitis (3) and AKI (1). The median CD34 dose was 7.17 (range 2.82 - 13.84). The median time to neutrophil engraftment was 9 days (range 6 - 12 days) and platelet engraftment was 12 days (range 9 - 18 days). The median number of blood components transfused included RBC 2 units (range 0 - 7), RDPs [14 units (range 0 - 38) and SDPs 1 units (range 0 - 8). There was a significant improvement in the EDSS score [mean 5.07 SD 1.77 to mean 4.73 SD 2.09; p value < 0.001] till the discharge. There was only one death. Thirteen (20%) patients had transient worsening of MS related symptoms post-AHSCT which resolved completely before discharge. The most common type of infection was urinary (50%).

Conclusions: HSCT is a safe and effective treatment option in improving disability scores in patients of MS with refractoriness to DMTs. Our study showed that HSCT is well tolerated treatment option in MS with acceptable mortality of 1-2 %. However, long term follow up is needed to look for the response.

Disclosure: Nothing to declare.

P062 Outcome of Autologous Hematopoietic Stem Cell Transplantation for Refractory Takayasu Arteritis, A Retrospective Survey from the Autoimmune Diseases Working Party (ADWP) of the Ebmt

Charlotte Laurent1, Zora Marjanovic2, Laure Ricard2, Joerg Henes3, Remy Dulery2, Manuela Badoglio2, Dominique Farge4, John Snowden5, Dania Moraes6, Juliana Dias6, Mohamad Mohty2, Michael Soussan7, Renate Arnold8, Olivier Fain1, Tobias Alexander8, Maria Carolina Oliveira6, Arsene Mekinian2

1Saint Antoine Hospital, INSERM UMR 938, Sorbonne University, Paris, France, 2Saint Antoine Hospital, Paris, France, 3University Hospital Tuebingen, Tuebingen, Germany, 4Hôpital Saint-Louis, Paris, France, 5Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom, 6University of São Paulo, Ribeirão Preto, Brazil, 7AP-HP, Hôpital Avicenne, Paris 13 University Bobigny, France, 8Charité - Universtiy Medicine Berlin, Berlin, Germany,

Background: Takayasu arteritis (TAK) is a chronic granulomatous large-vessel vasculitis, commonly affecting young women, characterized by arterial thickening and fibrosis leading to stenosis and vascular occlusions. More than 10% of patients are refractory to conventional immunosuppressive disease-modifying drug (DMARD) therapy and are at high risk for vascular complications. Autologous hematopoietic stem cell transplantation (AHSCT) has emerged as a promising treatment option in severely affected and refractory patients with various autoimmune diseases. Several case-reports and small case series demonstrated the potential efficacy and safety of AHSCT for systemic vasculitis, particularly ANCA-positive vasculitis and Behçet’s disease. This study, approved by the ADWP, aims to evaluate the use and outcome of AHSCT in adult TAK patients.

Methods: This is a retrospective survey of patients reported to the EBMT data management between 1998 and 2018, who received AHSCT primarily for TAK. A specifically designed questionnaire was sent to each referring transplant centre to obtain all relevant clinical and laboratory data. Remission was defined as no evidence of inflammation or worsening of vessel disease.

Results: Data from six adult patients treated with AHSCT between 2003 and 2018 for refractory Takayasu have been identified. Median (range) follow-up was 9.9 (1-14) years. Five patients were female (83%), median age was 25 (9-39) years at diagnosis and 28 (22-41) years at AHSCT. All patients were pretreated with a median of 6 (4-8) lines of therapy, including systemic corticosteroids (in 6 patients), methotrexate (5 patients), cyclophosphamide, mycophenolate mofetil or infliximab (4 patients), tocilizumab or etanercept (2 patients), and other biologic or conventional-synthetic DMARDs. Mobilization was performed with cyclophosphamide 2g/m2 (4 patients) or 4g/m2 (2 patients) in combination with granulocyte-colony stimulating factor (G-CSF). The graft was CD34 positive selected in 2 cases. Conditioning included cyclophosphamide 200 mg/kg in 5 patients, and cyclophosphamide 120 mg/kg plus fludarabine 90 mg/m2 in one patient. All patients received rabbit anti-thymocyte globulin. After AHSCT, 4 patients received G-CSF during a median of 5 (5-6) days. A median of 3.9 (2-4.20) x 10˟6 CD34+cells /per kilogram were reinfused. Engraftment, defined as neutrophils ³0.5 x10^9/L and platelet ³20 x10^9/L were detected at a median of 8 (5-13) and 8 (5-11) days, respectively. All patients had active disease before AHSCT. At six months post-transplantation, remission was obtained in all cases, which persisted at 12 months in 5 cases. Four patients reactivated TAK at a median time of 27 (7-52) months after AHSCT, and 3 resumed disease-modifying therapy. During follow-up none of the patients developed secondary malignancy and one patient had a miscarriage. At last follow-up, all patients were alive, 2 patients were in remission (off-therapy), 2 patients improved compared to baseline, and 2 patients were in complete and partial remission, respectively, under immunosuppressive treatment.

Conclusions: This small retrospective series demonstrates that AHSCT has the potential to provide significant clinical responses in TAK patients who had been unresponsive to previous immunosuppressive therapy, with an acceptable safety profile. Therefore, AHSCT may be considered as a ‘clinical option’ for patients with severe, treatment-resistant and poor-prognosis TAK, ideally before the development of compromised vital organ function.

Clinical Trial Registry: na

Disclosure: JAS declare.s speaker fees at educational events supported by Sanofi, Janssen, Jazz, Mallinckrodt and Gilead

P063 The use of Autologous Haemopoetic Stem Cell Transplantation (aHSCT) in Multiple Sclerosis after Alemtuzumab Treatment Failure: A Case Series

Simon Bell1, Helen Jessop2, Andrew Chantry2, Basil Sharrack1,2, John Snowden2

1University of Sheffield, Sheffield, United Kingdom, 2Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom

Background: Disease modifying therapies (DMT) for RRMS have been the mainstay of treatment for 20 years. Alemtuzumab is one of the most highly efficacious DMT for RRMS. However some patients continue to experience disease activity despite adequate Alemtuzumab therapy. AHSCT has been used with increasing frequency over the last decade to treat very active RRMS despite the use of DMTs. However efficacy and timing of delivering treatment in patients who failed Alemtuzumab remains unclear. Here we report a case series of patients with RRMS who received AHSCT after failing to respond to Alemtuzumab treatment.

Methods: A case series of all patients who received AHSCT for RRMS after failing to respond to a full course of Alemtuzumab was compiled. Details of 4 cases were collected from a national referral centre in the north of England. Clinical details, MRI changes, efficacy and safety data related to the use of Alemtuzumab and AHSCT were recorded. AHSCT was performed using a standard Cyclophosphamide / ATG mobilization and conditioning regime.

Results: All patients experienced clinical and radiological evidence of disease activity and progression whilst on Alemtuzumab. The mean treatment period with Alemtuzumab was 27 months (SD 23.2 months). Mean treatment courses was 2.5. Mean follow up after AHSCT was 48.5 months (SD 32.7). No patient experienced further relapses or MRI disease activity following AHSCT. EDSS scores improved in all patients following AHSCT (mean 1.12 points, SD 0.62). Patients experienced routine grade 1-3 complications during transplantation period. No autoimmune complications were recorded.

Conclusions: Our data suggests that AHSCT use is effective and safe in patients who failed to respond to Alemtuzumab.

Clinical Trial Registry: No Applicable

Disclosure: John Snowden declare.s speaker fees at educational events supported by Sanofi, Janssen, Jazz, Mallinckrodt and Gilead.

P064 Autologous Hematopoietic Stem Cell Transplantation for Treatment of Systemic Sclerosis, an Option for Refractory Patients

Claudia Sossa1,2, Javier Figueroa3, Juan Manuel Herrera4, Angela M Peña1, Luis A Salazar1, Manuel Rosales1, Enrique Pedraza3, Elena Mora3, Xueyi Chen2, Maria Luna-Gonzalez2, Jose Patricio Lopez-Lopez1

1FOSCAL, Bucaramanga, Colombia, 2Universidad Autónoma de Bucaramanga, Bucaramanga, Colombia, 3Clínica de Marly, Bogotá, Colombia, 4Centro Médico Imbanaco, Cali, Colombia

Background: Autologous hematopoietic stem cell transplantation (aHSCT) is a promising therapeutic modality for severe autoimmune diseases, especially as a treatment option for systemic sclerosis (SS). The aim of this study was to describe clinical experience in the use of aHSCT for SS in three centers in Colombia.

Methods: We conducted an observational study of adult patients diagnosed with SS and treated with aHSCT at centers from three different cities of Colombia from 2010 to 2019. Patients with SS were autografted in the centers with peripheral blood stem cells. The autografts were performed after conditioning with cyclophosphamide and BEAM chemotherapy. Laboratory results and complications after aHSCT were evaluated. Patients were follow-up to 3 years.

Results: Information from 13 patients were collected from the three centers. Median age was 44 years (27-53). We included 11 females (85%) and 2 males (15%). As a first-line treatment, 11 patients (84,6%) were treated with steroids. Median dose for cyclophosphamide at mobilization was 2,3 mg/m2 (2-3,5 mg/m2). About conditioning treatment, cyclophosphamide was performed in 12 patients (92,3%), while BEAM chemotherapy was performed in 1 patient (7,7%). The total number of viable CD34+ infused cells ranged between 3,1-25,57x106 (average 8,1). Patients recovered ≥0.5x109/L absolute granulocytes by day 14 (8-43 days), and platelet values were also ≥20x109/L by day 14 (6-43 days). Febrile neutropenia presented in 4 patients (30,7%), mucositis in 2 patients (15,3%), Pneumocystis jiroveci Pneumonia in 4 patients (30,7%) and 1 patient presented cytomegalovirus reactivation (7,7%). Only 1 patient (7,7%) presented cardiovascular complications and another patient (7,7%) presented endocrine complications. To date, there have been no deaths attributable to the transplant, yielding a 3 years overall survival of 100% and progression-free survival was 92,3% for all the patients.

Conclusions: AHSCT reduces the risk of all-cause mortality and has properties of a disease-modifying antirheumatic treatment in SS patients, leading to a high overall survival time. AHSCT should be proposed for carefully selected patients with refractory SS, therefore, optimal patient selection, pre-transplantation workup and posttransplant management need to be stablished.

Disclosure: Nothing to declare.

P065 A Pilot Feasibility Study of non-myeloablative Allogeneic Hematopoietic Stem Cell Transplantation for Refractory Crohn Disease

Richard Burt, Kathleen Quigley, Indira Arnautovic, Xiaoqiang Han

Northwestern University, Chicago, IL, United States

Background: Autologous hematopoietic stem cell transplantation (HSCT) induces remission of refractory Crohn disease (CD) but approximately 50% and 80% relapse and restart standard therapies at 3 and 5 years, respectively, post HSCT. We, therefore, undertook a pilot study of allogeneic HSCT using either matched sibling donor or umbilical cord blood (UCB), if a matched donor was not available.

Methods: Eligible patients were 18 to 45 years old, had an established diagnosis of Crohn disease, failed corticosteroids, 5-aminosalicylate, and at least two anti-TNF (infliximab, adalimumab, or certolizumab) drugs with a Crohn disease activity index (CDAI) between 250 to 400 or Craig Severity Score (CSS) > 17. Donor preference was given for unmanipulated healthy adult HLA 6 / 6 matched sibling, followed by unrelated 6/6 matched UCB and then unrelated 5/6 matched UCB. When available two UCB units were infused. The conditioning regimen was dose escalated during the protocol’s duration in an attempt to maximize donor engraftment. Conditioning drugs were: 1) cyclophosphamide 200 mg/kg divided as 50 mg /kg on days -5,-4,-3 and -2, 2) fludarabine (75 to 150 mg / m2) divided as 25- 30 mg /m2 /day (between days -7 to -3), and alemtuzumab (60 mg to 90 mg) divided 30 mg day (between days -3 to -1). Cyclosporine (100 mg po bid) or tacrolimus (1.0 mg bid) was initiated on day -2 and continued for 9 months.

Results: Average time of hospital engraftment and hospital discharge was day 13 and 14, respectively, with no difference in mean day of engraftment or discharge between matched sibling versus UCB transplantation. The mean number of red blood cell and platelet transfusions were both 3.4. Neutropenic infections included one case each of diarrhea due to clostridium difficile, and blood cultures positive for Escherichia coli, Enterococcus faecalis, and extended broad spectrum beta-lactamase producing Escherichia coli. Late post discharge events were tacrolimus-induced chronic renal failure mandating renal transplantation in a patient with a history of pre-transplant tacrolimus induced acute renal failure, surgery for colonic stricture without evidence of active Crohn disease that was complicated by bowel perforation and pseudomonas sepsis, and one death 3 months post HSCT from disseminated adenovirus infection. Following the patient’s death enrollment was terminated. There was no acute GVHD and one case of possible limited chronic GVHD.

Despite no evidence of donor engraftment, all patients entered and maintained without treatment a clinical remission (CDAI < 150), MRI imaging remission, endoscopic and histologic remission for the 5 years of study follow-up.

Conclusions: Complete treatment-free 5-year remissions without donor engraftment suggests that the conditioning regimen and nine months of maintenance tacrolimus, not the allogeneic hematopoietic stem cells, were responsible for remission. Alternatively, the infused donor graft may have provided a non-CD3+, non-CD33+ non-hematopoietic type of stem cell such as donor mesenchymal stem cells that in theory could facilitate a durable remission

Clinical Trial Registry: FDA IND 16908, www.clinicaltrials.gov NCT 01288053

Disclosure: Nothing to declare.

CAR-based Cellular Therapy – clinical

P066 National Implementation of the use of Tisagenlecleucel in Paediatric and Young Adult Patients with Acute Lymphoblastic Leukaemia (ALL) in National Health Service England (NHSE)

Caroline Louise Furness1,2, Rachael Hough3, Michelle Cummins4, Gillian Murphy5, Sara Ghorashian6, Persis Amrolia6, Claire Roddie3, Maeve O’Reilly3, Robert Wynn7, Denise Bonney7, David Marks4, Sridhar Chaganti8, Geoff Shenton9, Anna Castleton10, Eleni Tholouli11, Deborah Yallop12, Peter Clark13, John Snowden14

1Royal Marsden Hospital, Sutton, United Kingdom, 2The Institute of Cancer Research,, London, United Kingdom, 3University College London Hospitals, London, United Kingdom, 4University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom, 5Patient Representative, NCCP ALL Panel, United Kingdom, 6Great Ormond Street Hospital, London, United Kingdom, 7Royal Manchester Children’s Hospital, Manchester, United Kingdom, 8Queen Elizabeth Hospital, Birmingham, United Kingdom, 9Newcastle Upon Tyne NHS Foundation Trust, Newcastle upon Tyne, United Kingdom, 10Christie NHS Foundation Trust, Manchester, United Kingdom, 11Manchester University NHS Foundation Trust, Manchester, United Kingdom, 12Kings College Hospital NHS Foundation Trust, London, United Kingdom, 13Cancer Drugs Fund, NHS England, London, United Kingdom, 14Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom

Background: Following European Medicines Agency (EMA) approval of Tisagenlecleucel (KYMRIAH®) for the treatment of relapsed/refractory acute lymphoblastic leukaemia (ALL) in children and young adults in 2018, England established a structured funding programme via the National Health Service England (NHSE) Cancer Drugs Fund.

Methods: NHSE established a national CAR-T clinical panel for ALL (NCCP ALL). The aim of the NCCP ALL was to review cases to confirm eligibility against published criteria in line with the ELIANA study inclusion criteria and ensure prompt national access to Tisagenlecleucel. All CAR-T centres (3 open at NCCP set up and 9 open at 1 year review) were accredited for the Immune Effector Cell Standards in the 7th edition of the JACIE Standards in line with EBMT/JACIE recommendations (Yakoub-Agha et al 2019). The NCCP ALL consisted of representatives from NHSE, CAR-T centres, patient representation and independent ALL clinical experts. We describe panel experience over a one year period.

Results: The NCCP met by weekly teleconference to review cases referred by individual CAR-T centre lead clinicians who endorsed eligibility. Approval for access to Tisagenlecleucel was granted through unanimous panel consensus agreement following review of eligibility criteria (according to disease and CD19+ status, absence of CNS disease, performance status and organ function). Allocation to centre was achieved by review of geography, slot availability and patient preference.

From 19.11.2018-18.11.2019 34 patients were approved (age range 9 months - 21 years, median age 10.5 years). 5 did not proceed to leukapheresis (2 incorrect diagnosis of relapse, 1 received alternative CAR-T clinical trial product, 2 unable to proceed due to disease progression/complications). At time of abstract submission 23/29 (79.3%) patients had undergone CAR-T infusion. 3 patients who underwent leukapheresis were unable to proceed to infusion (1 patient due to emergence of CD19 negative disease, 1 patient due to CNS disease progression, 1 patient received cranial radiotherapy to control CNS disease and suffered frank bone marrow relapse treated with Inotuzumab followed by a failed manufacture). 3 patients await infusion. Mean time from panel approval to leukapheresis was 15 days (range 0-47 days) and mean time from leukapheresis to CAR-T infusion for patients infused was 64 days (range 35 - 92 days) Of 15 patients evaluable beyond 100 days (8 patients yet to reach this time point), 11 have a documented status of ‘alive in MRD negative remission’. This represents 73% patients infused (11/15). Brief toxicity and follow up data will be reported at EBMT 2020 with future planned efficacy analysis.

Conclusions: The establishment of a national panel in England for Tisagenlecleucel approval has allowed prompt, equitable and trackable access to this CAR-T product for ALL. From a worldwide perspective, NHSE is one of the first health services to introduce a national co-ordinated access programme of care and will utilise programme data to assess real world outcomes for patients treated with Tisagenlecleucel.

Disclosure: Nothing to declare.

P067 Real-world Clinical Features of Neurotoxicity Complicating CD19-targeted Chimeric Antigen Receptor (CAR) t-cell Therapy for High Grade Lymphoma and Management Including the off-label use of Anakinra

Shafqat Inam, Sean Apap Mangion, Victoria Potter, Reuben Benjamin, Andrea Kuhnl, Robert Hadden, Robin Sanderson

King’s College Hospital NHS Foundation Trust, London, United Kingdom

Background: Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are the main toxicities complicating CAR T-cell therapy. High dose steroids are the current standard of care, though there remains a clinical need for patients that are refractory to front line treatment. Animal models have supported cytokine targeting therapies that can cross the blood brain barrier such as the IL-1 receptor antagonist anakinra. We report our experience with ICANS in a cohort of patients receiving CD19 CAR T-cells, including the first series of patients treated with anakinra for ICANS.

Methods: Patients with relapsed/refractory B cell non-Hodgkin lymphoma received axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisagen) between Jan 2019 and September 2019. Eligibility was determined independently by a panel of clinical experts from NHS England and data collected prospectively. ICANS was graded according to ASTCT Consensus Grading.

Results: A total of 43 patients received treatment (14 transformed FL, 2 PMBCL and 27 DLBCL): 38 received axi-cel and 5 tisagen. 14 of 43 patients (33%) experienced any grade of neurotoxicity, with 7 of 43 (16%) grade 3 or 4, lower than the rate reported in previous trials and real-world data. The most common clinical features were disorientation or confusion, dyspraxia and expressive dysphasia (n=9). Intensive care admission was required for 8 patients, with 3 requiring intubation.

Neuroimaging was performed in 13 patients: five patients with CT brain, five with CT and MRI brain, and three MRI. The only clear acute change was bilateral hippocampal enhancement for one patient on MRI, subsequently attributed to viral encephalitis. Lumbar puncture was performed in six patients: glucose and cytology was normal, with a mild rise in CSF protein (mean 0.96g/L, range 0.25-0.45g/L). One patient was diagnosed with HHV6 encephalitis. EEG was performed in 12 patients, with almost all (92%) displaying encephalopathic features (generalised rhythmic delta activity) and 2 (17%) with epileptiform foci over the left fronto-temporal region. No periodic discharges or seizures were captured.

High dose steroids (dexamethasone up to 40mg daily) was started for 11 patients for treatment of ICANS; all patients had received tocilizumab for prior or concurrent CRS. Anakinra was administered to five patients concurrently with steroids for ICANS that was high grade or not responsive to initial therapy with dexamethasone. The ICANS grade for these five patients at time of treatment was grade 3 for two patients, and grade 4 for three patients. Anakinra was given as 200mg daily subcutaneously, started at a median of 3 days (range 1 to 5) after the commencement of dexamethasone for ICANS treatment, and median number of 5.4 doses given (range 3 to 8). ICANS resolved in all patients surviving to day 30 (n=13), with persistent neurological features in one patient likely sequelae of viral encephalitis and one treatment related death (sepsis).

Conclusions: We describe the clinical features of ICANS in our real-world cohort of patients receiving standard of care CD19 CAR T-cells, and demonstrate the feasibility of anakinra in combination with dexamethasone for treatment ICANS that is severe or not initially responsive to high dose steroids.

Disclosure: Nothing relevant to declare.

P068

Abstract already published.

P069

Abstract already published.

P070 Association of axi-cel CAR-T Cell Concentration with Treatment Response and Side Effects and Impact of Dexamethasone Treatment on Kinetics

Francis Ayuk1, Anita Badbaran1, Carolina Berger1, Tanja Sonntag1, Kritoffer Riecken1, Maria Geffken1, Dominic Wichmann1, Nicolaus Kröger1, Boris Fehse1

1University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Background: Chimeric-antigen-receptor (CAR-) T cells have demonstrated remarkable efficacy in the treatment of B-cell hematological malignancies, leading to the recent approval of two CD19-CAR-T cell products (Tisagenlecleucel/Kymriah and Axicabtagene ciloleucel/Axi-cel/Yescarta) in the US and Europe. CAR-T cell engraftment and expansion represent crucial parameters for efficacy of treatment. Monitoring of CAR-T cell concentrations has however been limited by the lack of diagnostic assays.

Methods: We performed prospective serial measurements of CAR-T cell levels in blood and body fluids of 18 patients treated with Axi-cel. Informed consent was obtained from all patients and the study approved by the ethics committee. Per protocol, blood samples are collected on days 0, 3, 7, 10, 14, 21, 28, 35, 56, 84, 180 and 365 after CAR-T cell infusion. In case of ICANS and lumbar puncture, cerebrospinal fluid (CSF) is also analyzed for CAR-T cell numbers. Quantification of CAR-T cells was performed using a newly developed digital PCR assay (Fehse et al., EBMT 2020).

Results: We have treated 18 patients with diffuse large B cell lymphoma with Axi-Cel. Sixteen of these patients were evaluable for day 30 response at time of abstract submission. CAR-T cells could be detected in the blood of all 16 patients, expansion and contraction followed the expected kinetics with median peak value of 11.2 CAR-T cells on (median) day 11.5 after infusion. Clinically, we observed only 2 responses (1PR, 1 CR) in 7 patients who had poor expansion of CAR-T cells (defined as peak numbers below and peak time-points above median), while 9 out of 10 patients with comparatively good expansion showed response (5 CR, 4 PR) on day 30. Seven out of 10 patients with good expansion experienced CRS and/or ICANS whereas only 2 of 7 patients with poor expansion had CRS or ICANS. CSF was collected from 3 patients with ICANS. In all 3 cases, high concentrations of CAR-T cells were detected in CSF. Two patients received dexamethasone for the treatment of ICANS. In both cases, treatment with dexamethasone (1 dose and 6 doses of 10mg respectively) led to a drop in the concentration of CAR-T cells, followed by recovery after discontinuation of dexamethasone (Figure 1). Data on more patients and cytopenias will be presented at the meeting.

Conclusions: Despite the relatively small patient number, our data emphasize the importance of monitoring CAR-T concentrations after infusion and indicate an association with response and side effects. CAR-T cell proliferation appears to bounce back after treatment with dexamethasone.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (11)

[Figure 1]

Disclosure: FA has received honorarium from Kite/Gilead for advisory board. NK has received honorarium from Kite/Gilead for advisory board. The dPCR assay used in this work has been made available as an “Expert Design Assay” based on agreement with Bio-Rad. BF, AB, CB, and KR would profit from potential future commercialization of the assay.

P071 Nivolumab as Salvage Therapy in Patients who Failed to Achieve Complete Remission after anti-CD19 CAR T-cell Therapy for DLBCL

Nicolas Gazeau1, David Beauvais1, Salomon Manier1, Marie De Charette de la Contrie1, Micha Srour1, Pauline Varlet1,3, Myriam Labalette1,2, Franck Morschhauser1, Ibrahim Yakoub-Agha1,2

1CHU de Lille, Université de Lille, Lille, France, 2LIRIC, INSERM U995, Lille, France

Background: We report the efficacy and tolerance of nivolumab (Nivo) in patients who did not achieve a complete response (CR) at one month after YescartaTM infusion.

Methods: Thirty-two patients with R/R DLBCL (13 male/19 female) were candidate for YescartaTM and underwent leukapheresis between November 2018 and December 2019 in our center. As of December 15, 2019, 29 were infused, 2 patients are waiting to be infused and one patient never got infused because CAR T-cell production failed twice. Twenty-five patients are evaluable for response at one month post CAR T infusion since one patient died at day 21 of septic shock. Median follow-up was 152 days (range, 39-354 days).

Results: Response rates according to IWC 2014 (Cheson 2014) at one month after CAR T-cell infusion were CR (n=11; 42%), partial response (PR) (n=5, 19%), stable disease (SD) (n=3: 12%), progressive disease (PD) (n=6; 23%). One patient with PR converted to CR two months after CAR T-cell infusion without subsequent treatment. All patients who achieved CR are alive and received no further treatment. All but 4 of the 13 patients who did not achieve CR received salvage therapy with Nivo. The 9 patients (3 PR, 3 SD and 3 PD) received Nivo at the dose of 240 mg/2 weeks. All patients received prophylaxis with valaciclovir and cotrimoxazole. Median time of the onset of Nivo was 60 days (range, 37-144 days) after CAR T-cell infusion. Median number of Nivo injections was 5 (range, 2-9). Two out of the 3 patients with PR achieved CR 60 days after initiation of Nivo. One of them subsequently received allogeneic hematopoietic cell transplantation and one is still receiving Nivo. In this latter patient, circulating CAR T-cells, mainly CD8+, dramatically increased following Nivo administration. One out of the 3 patients with PD experienced PR 60 days after Nivo. The 6 remaining patients with PR, SD and PD progressed after Nivo, of whom 2 died at day 90 and 173 after initiation of Nivo. Table 1 depicts outcomes of all patients who received Nivo. Three patients developed grade 2 bacterial pneumonia and one patient who received subsequent allo-HCT developed grade 1 psoriasis that was probably linked to Nivo. Overall, response to Nivo was recorded as CR (n=2, 22%) and PR (n=1, 11%). Six patients (67%) progressed.

Conclusions: Nivo seemed to be effective and safe in a small number of patients who did not achieve CR after CAR T-cell therapy.

Patients #/sex/age in yearsResponse to CAR T-cell therapy at one monthOnset of Nivo after CAR T-cell infusion (days)Number of injectionsMain side effectsResponse to NivoCurrent NivoTreatment after NivoCurrent status and survival after CAR T-cell therapy (days)
1/M/59PR865psoriasisCRstoppedAllo-HCTAlive 354
2/M/39PR1334-PDstoppedAllo-HCTDied 306
3/F/63SD835-PDstoppedSupportive careAlive 275
4/F/69PR1445pneumoniaCRongoing-Alive 227
5/F/53PD375-PDstoppedIbrutinib lenalidomideAlive 220
6/F/63PD519pneumoniaPRongoing-Alive 179
7/M/55SD602-PDstoppedSupportive careDied 150
8/F/74SD464pneumoniaPDstoppedSupportive careAlive 153
9/F/67PD393-ongoingongoing-Alive 76

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[Table1. Patients’ outcome after Nivo administration]

Disclosure: Nothing to declare.

P072 Surveillance of Minimal Residual Disease (MRD) in Diffuse Large B Cell Lymphoma (DLBCL) by Circulating Tumor Dna (CTDNA) Profiling after Chimeric Antigen Receptor T (CAR-T)

Houli Zhao1,2,3, Yongxian Hu1,2,3, Wei Ding1, Arnon Nagler4, He Huang1,2,3

1The First Affiliated Hospital, Zhejiang University, Hangzhou, China,2Zhejiang Province Engineering Laboratory for Stem Cell and Immunity Therapy, Hangzhou, China, 3Institute of Hematology, Zhejiang University, Hangzhou, China, 4Chaim Sheba Medical Center, Tel Hashomer, Israel, Tel Hashomer, Israel

Background: CAR-T therapy has become an ultimately effective solution for relapse or refractory (r/r) DLBCL. Therefore, after successful CAR-T therapy, patients are carefully monitored by positron emission tomography-computed tomography (PET-CT) instead of other treatment. Besides high cost, risk of ionizing radiation also limit the use of PET-CT in surveillance follow-up DLBCL. CtDNA derives from disrupted tumor cells preserving the characteristic of alteration in tumor genome. With the application of next generation sequencing (NGS), analysis large-scale sample of DNA become cheaper and faster showing great potential prospect in “liquid biopsy” avoiding the risk of failure of biopsy, surveillance of MRD in lymphoma, and observation of lymphoma subclone evolvement with early precise intervention.

Methods: We retrospectively collected clinical data, tumor sample preserved in formalin fixed paraffin-embedded tissue or liquid nitrogen storage and serum preserved in liquid nitrogen storage from the prospective clinical study aiming to evaluate the safety and efficacy of anti-CD19 CAR-T for r/r B cell lymphoma (ChiCTR-OCC-15007008). We profiled genome aberration with NGS in the baseline, relapsed, and progressive tumor sample after CAR-T therapy and ctDNA in baseline serum and reviewing serum in accordance with reviewing PET-CT scan. 8 DLBCL patients received CAR-T therapy between December 2016 and November 2017 were included in this analysis.

Results: The baseline characteristics are listed in table. The median follow-up is 322.5 days. 4 (50%) patients achieved complete response (CR), 1 (12.5%) patient achieved partial response and the rest of 3 (37.5%) patients showed no response 1 month after CAR-T therapy. 3 of 5 patients who achieved response relapsed within 4 months after CAR-T therapy while the rest of 2 patients remain CR for more than 20 and 27 months respectively.(Figure A) Grade 1, 2, and 3 cytokine release syndrome occurred in 2, 1, and 3 patients respectively. 89 and 446 hotspot genes NGS were performed in 1 and 7 patients respectively. Compared to PET-CT scan, the sensitivity and specificity of ctDNA profiling in detecting MRD is 94% and 64% respectively. Among 3 patients who relapsed from CAR-T, positive posttreatment ctDNA detection preceded PET-CT progression in patient 6 by 1.4 months (Figure B). The median number of abnormal genes in baseline tumor tissue is 4 and 15.5 (P=0.012) in the patients remained long-term CR and the patients failed from CAR-T therapy respectively. XPO1 E571K mutation was observed in 3 of 6 patients failed from CAR-T therapy.

Conclusions: CtDNA profiling is a promising new technique for surveillance of MRD in DLBCL after CAR-T therapy. In some cases, ctDNA can predict the disease progression earlier than PET-CT scan. A much number of abnormal genes in baseline particularly XPO1 E571K mutation may be a poor prognostic factor after CAR-T therapy in DLBCL.

Patient No.12345678
Age3527364443603350
Disease stageIVBIVBIVAIVAIIIAIIISBIVAIIA
Prior lines of therapy74335234
Prior ASCTYesNoNoNoYesNoNoNo

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[Baseline characteristics]

The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (12)

[Figure 1A. | Figure 1B. Positive posttreatment ct]

Clinical Trial Registry: ChiCTR-OCC-15007008

http://www.chictr.org.cn/

Disclosure: Nothing to declare.

P073 A digital-pcr Assay for Precise in-vivo Quantification of Adoptively Transferred CD19-car T Cells after Treatment with Axicabtagene Ciloleucel (AXI-CEL)

Boris Fehse, Anita Badbaran, Carolina Berger, Tanja Sonntag, Kristoffer Riecken, Maria Geffken, Nicolaus Kröger, Francis A. Ayuk

University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Background: Adoptive immunotherapy with CD19-specific CAR-T cells has shown excellent efficacy in late-stage relapsed/refractory B-cell cancers leading to the recent approval of two CD19-CAR-T cell products. Being ‘living drugs’, the in-vivo expansion, migration, contraction and persistence of CAR-T cells after infusion are important variables most probably impacting both disease response and treatment toxicity. Remarkably, widely available diagnostic tools to rapidly assess CAR-T-cell ‘drug levels’ in the clinical setting are largely missing. Digital PCR (dPCR) represents an advancement of quantitative PCR and is characterised by excellent sensitivity, specificity, and reproducibility making it an ideal tool for real-time diagnostics of rare events. Here we aimed at developing and evaluating a novel dPCR assay for detection and quantification of Axi-cel CAR-T cells in vivo.

Methods: To establish a CAR-specific dPCR assay, we first cloned and sequenced the complete cDNA of the Axi-cel vector construct. We designed different combinations of primers and dual-labelled hydrolysis probes, each amplicon spanning at least two different regions of the CAR vector. Three combinations of primers (A, B, C) were successfully tested on CAR-T cells, post-infusion PBMC, and negative controls in duplex reactions with the HCK reference (REF) gene; assay C was chosen for further application.

Results: For all three dPCR assays clear separation of negative and positive signals was observed (Fig. 1A) resulting in perfect specificity. Reproducibility tested on individual patient samples was excellent with neglectable intra- and inter-assay variations. Based on dilution curves (Fig. 1B) and the established negativity of non-transduced cells, the limit of detection was determined to be one single CAR copy. Considering Poisson distribution this translates into a limit of quantification of three copies, i.e. any sample containing a mean of three target copies in the test volume could be expected to become positive with a likelihood >95%. In 100 ng genomic DNA (gDNA; approximately 30,000 haploid genome equivalents) this corresponds to a sensitivity of 0.01%. For male patients, a Y-chromosome located haploid reference gene was employed, which allows doubling the gDNA input and thus dPCR sensitivity. After thorough assay validation, we proceeded to monitor adoptively transferred Axi-cel T cells in 16 patients with advanced B-cell lymphoma treated at our centre (with informed consent) using assay C. Mean vector copy numbers were first assessed in the Axi-cel products, using leftovers from the infusion bags. CAR-T cells were reliably detectable in post-infusion samples of peripheral blood, bone marrow, and body fluids. Actual CAR-T numbers were calculated taking into account vector copy and PBMC numbers at the time point of analysis. We found robust CAR-T-cell expansion in 10 of our 16 patients with peak levels of up to 132 CAR-T cells/µL. The pattern of early CAR-T cell expansion and long-term persistence followed the kinetics previously described for Axi-cel patients.

Conclusions: We have established a novel dPCR assay for sensitive detection of Axi-cel CAR-T cells in vivo. Our assay is excellently suited as a diagnostic tool to monitor the infused cells in real-time in different body fluids.

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[Figure 1]

Disclosure: The described dPCR assay is available as an ‘Expert Design Assay from Bio-Rad. BF, CB, AB, and KR would profit from commercialisation of the Assay.

P074

Abstract already published.

P075 Axicabtagene Ciloleucel CD19 CAR T-Cells for Relapsed/refractory Large b-cell Lymphoma: real-world Outcomes, Toxicity and Predictors of Response from a Prospective UK Cohort

Robin Sanderson, Reuben Benjamin, Piers Patten, Victoria Potter, Deborah Yallup, Kirsty Cuthill, Orla Stewart, Tony Pagliuca, Pramila Krishnamurphy, Shafqat Inam, Mili Shah, Shu Wong, Catherine Hockings, Victoria Metaxa, Andrea Kuhnl

King’s College Hospital NHS Foundation Trust, London, United Kingdom

Background: King’s College Hospital was an early UK commissioned centre delivering licensed axicabtagene ciloleucel (axi-cel) for the treatment of relapsed/refractory high-grade lymphoma starting in January 2019. Eligibility was determined through both NHS England’s National CAR Clinical panel and King’s College Hospital CAR multi-disciplinary team meeting for NHS and private patients respectively. Real-world European data is required to validate trial data and look for predictors of response and toxicity.

Methods: Eligible patients were aged >18 with diffuse large B-cell lymphoma (DLBCL), transformed follicular lymphoma (tFL) or primary mediastinal B-cell lymphoma (PMBCL), post 2 previous lines of treatment including anthracyclines. Adequate organ function was determined by King’s College Hospital and data on outcomes were collected prospectively.

Results: As of December 2019, 42 patients have been infused with axi-cel with a median follow-up of 6 months. The median age was 55 (range 18-73), 63% were male and 19% were aged 65 or over at infusion. All patients had ECOG performance status of 0-1 at time of referral. 27 (64%) had DLBCL, 12 (29%) transformed follicular lymphoma and 3 (7%) PMBCL. 11 patients had previous transplants (26%), 3 allogeneic and 8 autologous.

Median time from leukapheresis to infusion was 36 days. Most patients received bridging therapy between leukapheresis and infusion, 20 (47%) with chemotherapy, 8 (19%) with radiotherapy and 10 (23%) with steroids only.

Toxicity was graded as per consensus ASTCT guidelines (Lee et al. BBMT 2019) with 41 patients evaluable. Grade 3 cytokine release syndrome (CRS) occurred in 5 patients (12%) with no grade 4 or 5 events. 40 patients (98%) had CRS of any grade, with 32 patients (78%) being treated with tocilizumab for CRS grade 2 or above. 7 patients (17%) had grades 3 or 4 immune effector cell associated neurotoxicity syndrome (ICANS) with 14 patients (34%) experiencing any grade. 41% of patients received steroids for CRS or ICANS management. There was one grade 5 event from pneumonia and sepsis. 16 patients were treated on intensive care (39%), however 8 of these patients only required observation.

38 patients had an evaluable response at 1 month, with 82% overall response rate (ORR) and 37% complete metabolic remission (CMR), at 3 months of 34 evaluable patients 44% ORR and 23% CMR. Overall survival of the infused cohort was 67% and 14 (33%) patients have moved to further therapies. Median progression free survival (PFS) was 3.6 months and was significantly inferior in patients with 3+ prior therapies, with extranodal disease and with DLBCL compared to tFL.

Conclusions: CD19 CAR T cells have been safely delivered in the NHS and our large single centre cohort demonstrates lower toxicity with axi-cel, particularly of ICANS then described in a recent large CIBMTR cohort (Pasquini et al. ASH 2019). Initial response rates are high although PFS is lower than expected. Interestingly, 3+ prior therapies were associated with inferior PFS, implying patients may benefit from earlier referral for consideration of CAR T cells. By EBMT further follow-up will allow 6-month outcomes and predictors of response to be presented.

Disclosure: Sanderson, Robin - Advisory boards/honoraria: Novartis, Kite/Gilead.

Benjamin, Reuben - Advisory boards/honoraria: Novartis, Kite, Celgene, Takeda, Jannsen, Amgen. Research funding: Servier, Allogene, Pfizer.

Kuhnl, Andrea - Honoraria: Kite. Research funding: Novartis.

P076

Abstract already published.

P077 Sinusoidal Obstruction Syndrome in Patients with Relapsed/Refractory (R/R) b-cell Acute Lymphoblastic Leukemia (B-all) Treated with ari-0001 Cells

Valentín Ortiz-Maldonado1, Anna Alonso-Saladrigues2, Miguel Caballero-Baños3, Maria Castella3, Anna Boronat3, Enric García-Rey4, Tycho Baumann1, Marina Díaz-Beyá1, Montserrat Torrebadell2, Anna Faura2, Albert Català2, Federico Ramos2, Alicia Palomino1, Marta Gómez-Hernando1, Carlos Jiménez-Vicente1, Joan Cid1, Miquel Lozano1, Cristina Llanos2, Adrián Téllez1, Sara Fernández1, Pedro Castro1, Iolanda Jordán2, Jordi Esteve1, Josep Maria Canals5, Esteve Trias4, Jordi Yagüe1, Maria Suárez-Lledó1, Montserrat Rovira1, Alvaro Urbano-Izpizua1, Manel Juan3, Susana Rives2, Julio Delgado1

1Hospital Clinic, Barcelona, Spain, 2Hospital Sant Joan de Déu, Barcelona, Spain, 3Immunotherapy Platform Clínic-Sant Joan de Déu, Barcelona, Spain, 4Banc de Sang i Teixits, Barcelona, Spain, 5University of Barcelona, Barcelona, Spain

Background: Sinusoidal obstruction syndrome (SOS) is a life-threatening adverse event occurring mostly in the context of allogeneic hematopoietic stem cell transplant (alloHCT), with a mean incidence of approximately 14% (2-31%, depending on conditioning regimen and individual patient risk factors). Novel immunotherapy agents like inotuzumab-ozogamicin (IO) can also increase the risk of SOS in this setting. In the pivotal trial, the risk of SOS was 8.6% for patients who received standard of care therapy plus alloHCT and 24.6% for those who received IO plus alloHCT (Kantarjian HM, 2019). However, there is little data on the incidence of SOS after other novel agents like CAR-T cells.

Methods: The first academic pilot clinical trial (clinicaltrials.gov NCT03144583) using our fully academic (A3B1:CD8:4-1BB:CD3Z) CAR19 (ARI-0001 cells) finished recruitment in June/2019. Eligibility criteria included CD19+ R/R B-ALL (adult and pediatric), NHL and CLL who had failed standard available therapy. Lymphodepletion was with fludarabine (90 mg/m2) and cyclophosphamide (900 mg/m2), and the cell dose was 0.4-5 x106 ARI-0001 cells/kg, first as a single infusion (first 15 patients, cohort 1), and then in 2-3 fractions (last 23 patients, cohort 2). Here we report a descriptive analysis on the incidence of SOS in B-ALL patients included in this trial.

Results: We treated 38 R/R B-ALL patients with ARI-0001 cells. Median age was 24.5 years (3-68). All but 5 patients had relapsed after alloHCT (33/38 = 86.8%), and among patients with history of IO treatment (15/38 = 39.4%) only one had not previously undergone an alloHCT. We observed a total of 3 (7.9%) cases of SOS (see table 1) after ARI-0001 treatment, all occurring at cohort 2. The first 2 cases where 2 adult patients of 54 and 68 years diagnosed using the modified Seattle criteria in the context of weight gain, ascites, severe thrombocytopenia, increase in transhepatic gradient, and finally, confirmed by transjugular liver biopsy at day +31 and +49 after ARI-0001 cell infusion. Both patients had previous history of alloHCT and IO treatment with an inconclusive history of liver toxicity after IO treatment. They improved clinically from their SOS with support treatment and were eventually discharged from hospital. The third SOS case occurred in a post alloHCT young female patient (19 years) that after receiving ARI-0001 cell therapy was treated in another hospital with IO (day +161) and shortly after was diagnosed and treated as a SOS at day +171. This patient improved clinically after defibrotide treatment and was eventually discharged from hospital.

Conclusions: The incidence of SOS in patients with R/R B-ALL treated with ARI-0001 cells was 7.9%. However, it was 20% among those patients with both alloHCT and IO treatment. No SOS occurred in patients without prior alloHCT plus IO treatment. These results led us to incorporate liver imaging studies to our screening tests in patients with prior alloHCT/IO history who are referred for ARI-0001 cell therapy.

Clinical Trial Registry: Phase I, CART19-BE-01 clinical trial (EudraCT: 2016-002972-29, NCT03144583) for relapsed/refractory CD19+ leukemia and lymphoma at the Hospital Clínic de Barcelona and Hospital Sant Joan de Déu, Barcelona (Spain).

Disclosure: Source of funding: Proyecto ARI; Fundació Gloria Soler; ISCIII; CatSalut; FEHH; Generalitat de Catalunya

P078 Humoral Immune Response in Patients with CD19-positive Relapsed/refractory B-cell Malignancies Recruited into the CART19-be-01 Clinical Trial, an Academic CAR19

Nela Klein-González1, E. Azucena González-Navarro1, Ariadna Bartoló-Ibars1, Valentín Ortiz-Maldonado1, Montserrat Torrebadell2, Maria Castellà1,3,4, Daniel Benítez1, Miguel Caballero-Baños1, Raquel Cabezón1, Marta Español-Rego1, Tycho Baumann1, Eva Giné1, Pedro Castro1,3,5, Jordi Esteve2,3,5, Jordi Yagüe1,3,5, Susana Rives2, Álvaro Urbano-Ispizua1,3,5, Julio Delgado1,3, Manel Juan1,3

1Hospital Clínic, Barcelona, Spain, 2Hospital Sant Joan de Déu, Barcelona, Spain, 3Institut d’Investigacions Biomèdiques August Pi i Sunyer IDIBAPS, Barcelona, Spain, 4Banc de Sang i Teixits (BST), Barcelona, Spain, 5University of Barcelona, Barcelona, Spain

Background: Chimeric Antigen Receptor (CAR)-T cells directed against CD19 have induced high rates of response in patients with relapsed/refractory (R/R) B-cell malignancies. Two CD19-targeting constructs have been approved by the FDA and EMA for B lymphoblastic leukemia (B-ALL) and aggressive lymphoma. Despite deep remissions, there are still major challenges and disparate data are reported about the immunogenicity induced by CART-cell therapy. The Spanish Agency of Medicine approved our first clinical trial with a fully academic CART-19 on May/2017.

Methods: Patients with R/R B-ALL (adult and pediatric), non-Hodgkin’s lymphoma (NHL) and chronic lymphocytic leukemia(CLL) who failed standard therapy were included in the trial. The primary objective of the study was safety; secondary objectives were response rate and its duration. After lymphodepletion with fludarabine (90 mg/m2) and cyclophosphamide (900 mg/m2), a total dose of 0.5-5 x106 ARI-0001 cells/kg was infused (CAR-T with a single-chain variable fragment (scFv) with anti-CD19 specificity, conjugated with the co-stimulatory regions 4-1BB and CD3z; the scFv was originated from a mouse monoclonal antibody A3B1). The humoral anti-CART response was assessed by a cell-based fluorescence assay to detect human anti-murine antibodies (HAMA) in patients´ sera. Assessment was conducted at different time points: 1) at baseline (pre-dose), 2) on day 14 after the administration of ARI-0001 cells, 3) on day 28, 4) on day 100, and 5) every 3 months thereafter.

Results: Forty-seven patients (37 adults/10 pediatrics) received ARI-0001 cells. Thirty-eight patients had a diagnosis of R/R B-ALL (28 adults and 10 children); all but 5 had relapsed after allogeneic hematopoietic stem cell transplant (HCT). Seven patients had a diagnosis of NHL, four of them (57%) had relapsed after HCT, and 2 patients had a diagnosis of CLL. Median age was 27 years (3-68). Twenty-five per cent of the patients tested positive for the presence of anti-CAR antibodies, all of them post-dose, in contrast to previous data reported on Kymriah ® with a significant presence of pre-dose anti-murine CAR19 antibody. Of these patients, 8 patients presented with a weak, and 4 patients with a strong presence of HAMA. The last had lost the effectiveness of the CART-therapy at that time point since a simultaneous B-cell recovery was observed in the periphery. Moreover, three of them received a second dose of CART-19, which did not revert the relapse.

Conclusions: These data suggest the importance of the immunogenicity induced by CART-cell therapies. Immune monitoring should include the assessment of humoral response, especially before considering a second dose after relapse.

Clinical Trial Registry: Identifier: NCT03144583

https://clinicaltrials.gov/ct2/show/NCT03144583

Disclosure: Nothing to declare.

P079 Real-world Data from Kings College Hospital: Infection Complications Post CAR-T Treatment in high-grade B Cell non-hodgkin Lymphoma

Shu Min Wong, Mili Shah, Shafqat Inam, Andrea Kuhnl, Robin Sanderson

Kings College Hospital NHS Foundation Trust, London, United Kingdom

Background: Chimeric antigen receptor T (CAR-T) cells have shown promising results in treating patients with relapsed/refractory (R/R) B cell malignancies. With the recent approval of both axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisagen) for the treatment of R/R high-grade B non-Hodgkin lymphoma (NHL), we see more patients being referred for this novel therapy. There have been some published data looking at short- and long-term infection risks with this therapy and hypogammaglobulinaemia associated with B cell aplasia.1,2

We look at our cohort of patients being treated at Kings College Hospital with Axi-cel or Tisagen for R/R NHL to identify our incidence of short- and long-term infections and to identify risk factors that may contribute.

Methods: We collected our single centre’s data on patients treated with CD19 CAR-T cells from Jan-Aug 2019. Eligibility is determined independently by a panel of clinical experts from NHS England and clinical data collected prospectively.

Results: A total of 31 patients were treated with axi-cel and 3 patients with tisagen during this period. All developed neutropenic fevers with at least Grade 1 cytokine release syndrome (CRS). A total of 26 patients required tocilizumab for CRS and 12 patients needed steroids for Grade 2 CRS unresponsive to tocilizumab. 3 patients had positive blood cultures within the first 28 days of CAR-T infusion and only 1 patient required treatment for proven fungal chest at D28. In regards to late infections, one patient had pneumocystis pneumonia at 6 months and another had line associated acinetobacter sepsis at 2 months in the setting of persistent neutropenia. 8 patients had positive respiratory viruses with 5 achieving lymphocyte recovery post CAR-T. 25 patients had B cell aplasia pre-CAR-T therapy and by 1 month nearly all patients had B cell aplasia. Pre-CAR-T 10 patients had IgG levels < 4g/L with 2 having regular immunoglobulin replacement prior and at 1-month post treatment 14 patients had levels < 4g/L. 2 patients required regular immunoglobulin replacement post CAR-T; one was for bronchiectasis. The other patient had significant infections within the first 100 days, this included HHV6 encephalitis, recurrent E. coli UTIs, Kliebsiella bacteraemia and pneumonia; he was treated with antibiotics as well as immunoglobulin replacement. One patient in remission died suddenly in their local hospital of sepsis at 7 months. All patients had routine prophylaxis with aciclovir, co-trimoxazole and fluconazole; patients were changed over to posaconazole as per hospital policy if evidence of prolonged neutropenia.

Conclusions: In our cohort most patients treated with CAR-T cells did not appear to have an increased risk of early or late infections and this is despite CRS and administration of tocilizumab and steroids. There was 1 patient who had significant infections post CAR-T likely due to persistent neutropenia and lymphopenia and another who died of late sepsis. Despite significant B cell aplasia pre and post CAR-T the immunoglobulin levels in most patients remained >4g/L which suggests that the humoral immune system can remain intact despite B cell aplasia. Immunoglobulin levels will be correlated with 6-month outcomes in final analysis.

Disclosure: Nothing to declare.

P080 Senescent/exhausted Phenotype of CD19-targeted CAR-T Cells and Immunoregulatory Environment Correlate with Reduced Response to car-t Cell Therapy in Relapsed/Refractory B Cell Malignancies

Katia Beider, Michal J. Besser, Jacob Schachter, Ania Hava Grushchenko-Polaq, Valeria Voevoda-Dimenshtein, Maayan Ulman, Olga Ostrovsky, Elad Jacoby, Avichai Shimoni, Abraham Avigdor, Arnon Nagler

Sheba Medical Center, Tel Hashomer, Israel

Background: Chimeric antigen receptor (CAR) T cells have shown promising results in patients (pts) with B cell malignancies, yet up to 60% of the pts with diffuse large B cell lymphoma (DLBCL) will eventually relapse. Therefore, future efforts are needed to improve the outcomes of these pts.

Methods: A total of 22 pts with relapsed/refractory B cell malignancies, DLBCL (n=21) and ALL (n=1), were enrolled on a phase 1b/2 study (NCT02772198) of locally produced CD19 CAR T cells. All pts received a lymphodepleting preparative regimen with cyclophosphamide and fludarabine, followed by intravenous infusion of autologous CD19 CAR-T cells with a CD28 costimulatory domain. Clinical response was determined at 28 days following cell administration. Blood samples obtained prior to the lymphodepleting conditioning and at days 7, 14, 21, 30 and 60 after CAR T administration were collected. The manufactured CAR T products (n=11) were also subjected to immunophenotypic analysis.

Results: Clinically, 14 of 22 pts (63.7%) responded to CAR T therapy, 6 (27.3%) with complete response (CR), and 8 (36.4%) with partial response (PR). Analysis of the manufactured CAR T products revealed high CXCR3 expression (76% and 95% positive within the CD4+ and CD8+ subsets), indicating high migratory capacity of CAR T cells toward inflamed tissues. Furthermore, co-expression of CXCR4 (54% and 52% positive within the CD4+ and CD8+ cells) suggests increased homing ability of the manufactured CAR T toward CXCL12-rich bone marrow and lymph nodes. Interestingly, higher CCR7 expression (27.5% vs 8.5%) and lower CCR6 levels (14% vs 28%) were detected on CD8+ CAR T cells from responding pts who achieved CR and PR (n=8) versus non-responders (n=3), suggesting that less differentiated phenotype together with increased trafficking of CAR T to lymphoid tissue corresponds with improved clinical outcome.

Additionally, we assessed the immunoregulatory and senescent/exhausted phenotype in the CAR T products. Low percentage of CD4+CD25+CD127- Treg cells (13.5%, range 7-18%) was detected, with no correlation to clinical response. However, significantly higher frequency of exhausted CD57+CD39+CD28- cytotoxic CD8+ cells stand out as signature population in CAR T products of non-responders in comparison to CR pts (37% vs 9.5%, p< 0.02).

It is known that immunosuppressive environment affects CAR T cell activation. Notably, responding and non-responding pts presented distinct Treg patterns. Pts achieving CR demonstrated modest and delayed increase in Treg cells, reaching maximal frequency of 23% Treg out of CD4+ cells (range 17-30%) at day 21 post-CAR-T infusion, declining to basal low levels (12.5%) at day 30. In contrast, non-responders possessed rapidly increasing % of Treg cells (35%, range 25-50%, at day 14 post-infusion). In line with this finding, notable increase in proportion of immunosuppressive CD11b+CD14+CD163+CD206+ myeloid cells was detected in blood of non-responders, while pts achieving CR experienced transient increase in myeloid suppressor cells at day 7 that went back to normal levels at day 14.

Conclusions: Overall, these results elucidate in part the mechanisms of CAR T traffic, immunosuppressive responses as well as induction of T cell senescence/exhaustion that most probably downregulate CAR T effectiveness as observed in non-responding pts.

Clinical Trial Registry: NCT02772198

Disclosure: Nothing to disclose

P081 Characterisation of Early and Late Cytopenias in Lymphoma Patients following Treatment with anti-CD19 CAR-T Therapy

Catherine Hockings, Andrea Kuhnl, Shu Wong, Mili Shah, Shafqat Inam, Piers Patten, Kirsty Cuthill, Tony Pagliuca, Deborah Yallop, Reuben Benjamin, Victoria Potter, Robin Sanderson

King’s College Hospital NHS Foundation Trust, London, United Kingdom

Background: The anti-CD19 CAR-T therapies Axicabtagene ciloleucel and Tisagenlecleucel are now in use in the UK for patients with high grade lymphoma refractory to chemotherapy. As part of their treatment schedule patients receive lymphodepletion with Fludarabine and Cyclophosphamide prior to CAR-T infusion. However, as well as early haematological toxicity attributable to these agents, a second wave of cytopenias is observed in some patients after initial count recovery.

Methods: 39 patients were admitted to King’s College Hospital between January and September 2019 and received anti-CD19 CAR-T therapy. Haemoglobin, neutrophil and platelet counts were interrogated from commencement of lymphodepletion until latest follow-up or myelosuppressive therapy for disease progression. Haematological toxicity was graded as per EORTC. Further clinical information was collected from electronic patient records.

Results: Of the 39 patients diagnoses totalled 28 DLBCL, 14 transformed FL and 1 PMBCL. 38 patients received Axi-cel, the remaining 5 received tisagen. Patients had follow up duration of between 2 and 11 months post infusion, median follow-up 169 days. Maximal early haematological toxicity, as well as at the time of response monitoring at day+28, day+100 and 6 months post treatment is summarised in the table below.

Almost all patients (38 of 39) experienced grade 3/4 neutropenia during the first 28 days post infusion. No patients were given GCSF prior to D+14 due to concerns regarding exacerbation of CRS but 18 received it subsequently. Despite this, grade 3/4 neutropenia persisted in almost half of patients at D+28 (43%, 16/37). Grade 3/4 haematological toxicity persisting at D+28 occurred in 43% of patients (9/21) with < /=3 prior lines of treatment compared to 56% (9/16) of patients with >/=4 previous regimens. Incidence was also equivalent in patients with or without prior HSCT: 44% (12/27) without, 50% (5/10) with. 13 patients received bridging chemotherapy between apheresis and lymphodepletion, whereas 26 received no bridging, steroids or radiotherapy. Recent chemotherapy correlated with cytopenia at D+28: no bridging chemotherapy 36% (9/25), bridging chemotherapy 75% (9/12) (P=0.029).

Rates of grade 2 or worse CRS were similar in those with or without cytopenias at D+28: 61% (11/18) vs 47% (9/19) patients. ORR was 80% on D+28 PET imaging in patients without grade 3 or 4 cytopenias (16/20) and 94% in those with cytopenias (16/17) (p=0.22). Haematological toxicity at D+28 was also compared to D+100 outcomes. 47% (8/17) of patients without D+28 cytopenias had a maintained response, compared to 44% of those with progressive disease (7/16).

Conclusions: Many patients experience late cytopenias following CAR-T, therefore close monitoring of blood counts is required following discharge. Persistent cytopenias on discharge appear to correlate with prior bridging chemotherapy and are not associated with responses at 3 month follow up. Further work, including correlation with cytokine levels, is needed to determine the cause of late cytopenias. With maturation and expansion of the patient cohort we hope to determine whether cytopenias may be related to expansion and persistence of CAR-T and correlate with positive outcomes.

Clinical Trial Registry: n/a

Disclosure: Nothing to declare.

P082 Impact of Ethnicity in R/R DLBCL and B-cell all Patients Treated with Tisagenlecleucel

Ahmed Abdelhady1, Hidefumi Hiramatsu2, Takanori Teshima3, Koji Izutsu4, Koji Kato5, Satoshi Saida6, Tatsuya Kamitori2, Keiji Tasaka2, Itaru Kato2, Katsutsugu Umeda2, Souichi Adachi7, Karen Thudium8, Edward Waldron8, Alessandra Forcina9, Andrea Chassot Agostinho8, Stephan Grupp10,11, Richard T. Maziarz12

1Novartis Pharmaceuticals, East Hanover, NJ, United States, 2Kyoto University, Kyoto, Japan, 3Hokkaido University Hospital, Sapporo Hokkaido, Japan, 4National Cancer Center Hospital, Tokyo, Japan, 5Kyushu University Hospital, Fukuoka Prefecture, Japan, 6Kyoto University, Kyoto, Japan, 7Kyoto University, Kyoto, Japan, 8Novartis Pharmaceuticals Corporation, East Hanover, NJ, United States, 9Novartis Pharma AG, Basel, Switzerland, 10Children’s Hospital of Philadelphia, Philadelphia, PA, United States, 11University of Pennsylvania, Philadelphia, PA, United States, 12Oregon Health and Science University, Portland, OR, United States

Background: We assessed the impact of ethnicity on efficacy, safety, and cellular kinetics in Asian and non-Asian relapsed/refractory (r/r) DLBCL or B-cell ALL patients infused with tisagenlecleucel (anti-CD19 CAR-T cell therapy).

Methods: Data were obtained from r/r DLBCL (JULIET, NCT02445248) and B-cell ALL (ELIANA, NCT02435849; ENSIGN, NCT02228096) patients.

Results: Safety, efficacy, cellular kinetics, transduced dose range, and immunogenicity in the Asian and non-Asian subgroups are summarized in the Table. The assessed product attributes (eg, total cell count, % T cells, viability, and transduction efficiency) were comparable between Asian and non-Asian patients.

Conclusions: Asian and non-Asian patient populations in both indications were comparable with respect to safety, efficacy, dose-response, product attributes, and cellular kinetics of tisagenlecleucel.

ELIANA and ENSIGNJULIET
Asian
(N=14)
Non-Asian
(N=123)
Asian
(N=10)
Non-Asian
(N=105)
Tisagenlecleucel transduced cell dose, median (range)

1.00 x 108 cells

(0.05 - 2.50 x 108)

1.08 x 108 cells (0.03 - 2.60 x 108)2.10 x 108 cells (1.00 - 4.90 x 108)

3.00 x 108 cells

(0.10 - 6.00 x108)

Within target dose range of cells transduced, n (%)12 (85.7)107 (87.0)10 (100)99 (94.3)
Efficacy
ORR, % [95% CI]64.3 [35.1-87.2]78.3 (n=115) [69.6-85.4]70.0 [34.8-93.3]50.5 [40.5-60.4]
DOR at 18mo, % [95% CI]70 [22.5-91.8]63.6 (n=115) [51.0-73.7]55.6 [7.3-87.6]62.4 [47.5-74.2]
OS at 18mo, % [95% CI]66.8 [32.4-86.6]64.4 [53.9-73.1]51.4 [14.3-79.6]43.1 [33.3-52.5]
Safety
Any-grade CRS by Penn scale, n (%)11 (78.6)97 (78.9)7 (70)59 (56.2)
Any-grade neurologic event by CTCAE v4.03, n (%)3 (21.4)57 (46.3)1 (10)30 (28.6)
AUC 0-28d (copies/ug*days), geo-mean (CV%)562000 (126.1)303000 (179.2)71800 (357.3)63900 (223.0)
Cmax(copies/ug), geo-mean (CV%)59900 (78.3)33300 (153.4)4520 (464.5)5740 (283.1)
Immunogenicity post infusion, positive n (%)4 (28.6)52 (42.3)1 (10)9 (8.6)

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AUC 0-28d, area under the curve of CAR-T cell numbers between day 0 and 28; CRS, cytokine release syndrome; CTCAE, Common Terminology Criteria for Adverse Events; CV, coefficient of variation; DOR, duration of remission/response; ORR, overall remission/response rate; OS, overall survival.

[Table: Safety, efficacy, cellular kinetics, transduced dose range, and immunogenicity in the Asian and non-Asian subgroups]

Clinical Trial Registry: NCT02445248, NCT02435849, NCT02228096

Disclosure: Ahmed Abdelhady: Employment: Novartis.

Hidefumi Hiramatsu: No relationship to disclose.

Takanori Teshima: Grants from Kyowa-Hakko Kirin, Novartis, Chugai, Sanofi, Astellas, Teijin Pharma, Fuji Pharma, Nippon Shinyaku; personal fee (honoraria and advisory board) from Merck Sharp & Dohme, Kyowa-Hakko Kirin, Takeda, Novartis, Pfizer, Bristol-Myers Squibb.

Koji Izutsu: Grants and personal fees from Novartis during the conduct of the study; grants and personal fees from Eisai, MSD, Takeda, Janssen, Mundipharma, Chugai, AbbVie, Bayer, Ono, Celgene; personal fees from Kyowa Hakko Kirin, Bristol Myers Squibb, Dainihon Sumitomo, Nihon Mediphysics, AstraZeneca; grants from Gilead, Zenyaku, Solasia, Symbio, Astellas, Amgen, Bayer, Daiichi Sankyo, outside the submitted work.

Koji Kato: Consulting or advisory role with AbbVie, AstraZeneca, Celgene, Chugai, Eisai, Janssen, and Novartis. Honoraria from Chugai, Takeda, MSD, Kyowa-Kirin, Janssen, Celgene, Ono, Dainippon-Sumitomo, AbbVie, Novartis. Research funding from Chugai, Takeda, Kyowa-Kirin, Abbvie, Eisai, Janssen, Novartis, Mundi, AstraZeneca, Celgene, Ono, MSD, Otsuka.

Satoshi Saida: No relationship to disclose.

Tatsuya Kamitori: No relationship to disclose.

Keiji Tasaka: No relationship to disclose.

Itaru Kato: No relationship to disclose.

Katsutsugu Umeda: No relationship to disclose.

Souichi Adachi: No relationship to disclose.

Karen Thudium: Employment: Novartis.

Edward Waldron: Employment: Novartis.

Alessandra Forcina: Employment: Novartis.

Andrea Chassot Agostinho: Employment: Novartis.

Stephan Grupp: Grants and personal fees from Novartis Pharmaceuticals, during the conduct of the study; personal fees from Jazz Pharmaceuticals, personal fees from Adaptimmune, personal fees from TCR2 Therapeutics, personal fees from Eureka Therapeutics, personal fees from Cellectis/Servier, outside the submitted work; In addition, Dr. Grupp has a patent Toxicity management for anti-tumor activity of CARs (WO 2014011984 A1) issued.

Richard T. Maziarz: Honoraria, Membership on an entity’s Board of Directors or advisory committees and Research Funding: Novartis; Consultancy and Honoraria: Incyte, Juno; Honoraria: Kite; Jazz Pharmaceuticals.

P083 Impact of different Chemotherapy Regimens and Duration of DLBCL on Lymphopheresis and car-t T-cell Immunophenotyping

David Hagin, Tal Freund, Liav Sela, Rinat Eshel, Odelia Amit, Yael Bar-On, Irit Avivi, Ron Ram

Tel Aviv University, Tel Aviv, Israel

Background: CD19-directed CAR T-cell therapy becomes a standard of care treatment for relapse/refractory DLBCL. Production of CAR-T cells requires transduction and expansion of the collected lymphocytes. However, little is known about the impact of disease duration and specific treatment regimens on the harvested lymphocytes. Additionally, no sufficient data on the impact of the lymphopheresis product on treatment outcome.

Methods: Tisagenlecleucel (KymriahTM, Novartis) was commercially approved in Israel on May-2019. Since June-2019, we performed in all sequential patients flow-cytometry-based-T cell subsets (naïve-cell, central-memory (Tcm), effector-memory (Tem) and terminally-differentiated-CD45RA+ cells (Temra)) in the apheresis and in the CAR-T. In addition, activation marker HLA-DR and exhaustion marker PD-1 were also evaluated in the paired samples. All patients had a follow-up PET-CT scan one-month post infusion for response evaluation. We analyzed the effect of disease duration and the pre-apheresis treatment regimens being administered on the apheresis T-cell immunophenotyping, as well as the correlation between immunophenotyping and treatment outcome.

Results: Between May and December 2019, 35 DLBCL patients were screened and considered for Tisagenlecleucel treatment. 29 (83%) patients underwent lymphopheresis and 21 patients received the product. The study cohort included 20 sequential patients for whom complete flow-based T cell immunophenotyping data were available. 30-day PET-CT was available in 12. Median age was 71 (range, 20-84) years and median duration of disease was 12 (range, 4-68) months. 38% received >3 lines of chemotherapy and 33% failed autologousHCT.

Of the different variables evaluated we observed statistically significant effect of bendamustine treatment(n=9) on apheresis T cell immunophenotyping resulting in lower percent of naïve CD4 T cells (CD45RA+CCR7+; 4.15±4.2% vs 10.4±7.5%, p=.05), higher percent of Tem CD4s (CD45RA-CCR7-; 71.3±15.9% vs 52.7±12.6%, p=.01), higher percent of PD1+ CD4 T cells (66.8±14.6% vs 41.5±17.9%, p=.27) and higher percent of activated HLA-DR+ CD4s and CD8s (68.2±17.5% vs 41.9±13.7%, p=.01 for CD4s, 63.7±20.8% vs 39.2±19.1%, p=.13 for CD8s). Prior autologous HCT was associated with a trend toward lower CD4 to CD8 ratio (0.459±0.146 vs 1.00±0.748, p=.076). Although immunophenotyping was not affected by the number of pre-pheresis treatment-lines, disease duration was correlated with lower percent of naïve CD4 (Spearman´s correlation coefficient=-.5, p=.02) and naïve CD8 T-cells (Spearman´s correlation coefficient=-.46, p=.04) (Figure 1).The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (14)

[Figure 1: Scatter plot of correlation between duration of disease and naïve CD4 and CD8 count]

Among all analyzed T cell characteristics, only higher percent of pre-pheresis HLA-DR+ CD4s and CD8s were associated with higher incidence of CR (beta .78, p=.05 and .47, p=.09, respectively).

Conclusions: While there remains insufficient data to solidly confirm our hypothesis, it is reasonable to assume that pre-lymphopheresis disease duration and treatment history may affect pheresis product, which in-turn, determines the final CAR T-cell product and response to treatment. Preliminary data from our small cohort suggests that pre-pheresis bendamustine treatment is associated with more mature, activated and exhausted CD4 T-cell phenotype. Improved phenotyping to include additional exhaustion markers, as well as follow-up post CAR T-cell infusion (by evaluating peripheral blood CD19-Ig binding T cells) is ongoing.

Disclosure: Nothing to declare.

P084 Chimeric Antigen Receptor (CAR) T Cell Therapy Followed by Hematopoietic Stem Cell Transplantation May Improve Progression free Survival in Patients with Relapse/Refractory B-cell Non-hodgkin Lymphoma

Haiwen Huang, Shuo Liu, Qian Zhu, Yishan Duan, Depei Wu

First Afilliated Hospital of Suzhou University, Suzhou, China

Background: Chimeric antigen receptor (CAR) T cells are emerging as a novel treatment modality that highly effective in the treatment of relapse/refractory B-cell lymphoma, providing alternative therapeutic options for patients who failed to respond to conventional treatment or relapse. Although highly remission rates have been reported with CAR-T cell therapy in relapse/refractory B-cell lymphoma, relapse or disease progression is common after CAR-T therapy. This current study is to better our understanding of whether consolidative hematopoietic stem cell transplantation(HSCT) confers superior survival outcomes to patients who got remission by CAR-T cells therapy.

Methods: Compare the efficacy and survival of CAR-T therapy followed by HSCT and CAR-T alone in patients with relapsed/refractory B-cell lymphoma. 30 cases with CR or PR disesse status after CAR-T cells therapy in the First Affiliated Hospital of Soochow University from 2017 to 2019 were included. 11 of these cases (36.7%) were treated with HSCT after CAR-T therapy, of which 7 cases were treated with autologous stem cell lymphoma(ASCT), and 4 cases were treated with allogeneic stem cell transplantation(Allo-SCT). 19 of these cases (63.3%) were treated with CAR-T only. Overall survival(OS) and progression-free survival(PFS) rates were estimated by the Kaplan-Meier method, and Survival comparison was analyzed by using the log-rank test.

Results: Kaplan-Meier survival curve indicated that PFS of the HSCT following CAR-T group were higher than the CAR-T group, and log rank test showed that the difference of survival curve was statistically significant (P = 0.044). The estimated 1-year and 2-year progression-free survival(PFS)were 90.9%and 50% respectively in the CAR-T followed by HSCT group. The estimated 1-year and 2-year progression-free survival(PFS)were 71.6% and 27.8% respectively in the CAR-T group. Kaplan-Meier survival curve analysis indicated that OS of the HSCT following CAR-T group were higher than the CAR-T group, while log rank test showed that the difference of survival curve was no statistically significant (P = 0.250). The estimated1-year and 2-year overall survival(OS) were 90% and 89.4% respectively in the HSCT following CAR-T group, the estimated1-year and 2-year overall survival(OS) were90%and66.2% respectively in the CAR-T group.

Conclusions: Hematopoietic stem cell transplantation(HSCT) appear to improve progression-free survival (PFS) for the patients achieving remission following CAR-T therapy with relapse/refractory B-cell lymphoma. Future prospective studies needed to clearly define the role of consolidative HSCT in the relapse/refractory B-cell lymphoma patients who attained remission from CAR-T infusion and importantly, better identify this strategy whether exhibits superior overall survival outcomes.

Disclosure: there is no conflict of interest or source of funding

P085 Challenges in providing good Leukapheresis Products for the Production of Car T Cells for Patients with Relapsed/Refractory NHL or ALL

Felix Korell1, Sascha Laier2, Sandra Sauer1, Sonia Jaramillo-Segura1, Elisabeth Lasitschka1, Kaya Veelken1, Hannah Hennemann1, Marie-Luisa Schubert1, Tim Sauer1, Petra Pavel2, Carsten Müller-Tidow1, Peter Dreger1, Michael Schmitt1, Anita Schmitt1

1University Hospital Heidelberg, Heidelberg, Germany, 2Insitute of Clinical Transfusion Medicine and Cell Therapy (IKTZ), Heidelberg, Germany

Background: In patients with relapsed or refractory B-lineage acute lymphoblastic leukemia (ALL) or B-cell non-Hodgkin’s lymphoma (NHL) therapy with chimeric antigen receptor T (CAR-T) cells has proven to be highly effective. As starting material for the production of CAR-T cells T lymphocytes from the patients are mandatory. To harvest sufficient lymphocytes, leukapheresis as first step in the production process has to be performed. This constitutes a challenge to the treating physicians with regard to timing of the apheresis in heavily pretreated patients suffering from rapid progressive disease and being treated by drugs with negative impact on T cells.

Methods: Data from 45 adult patients suffering from r/r DLBCL (68%), PMBCL (2%), MCL (4%), FL (2%), CLL (4%), ALL (13%) or multiple myeloma (5%) who received a leukapheresis for CAR-T cell production were analyzed. Apheresis procedures were effective using the Spectra Optia™ device. Peripheral blood counts pre- and post-apheresis, as well as leukapheresis product parameters were assessed. Further important tasks were the analysis of the medication used prior to apheresis and the optimization of the apheresis procedure. Fourteen leukapheresis products were produced for clinical trials including 11 patients in our in-house production HD-CAR-1 study.

Results: All patients qualified for leukapheresis due to the following criteria: hemoglobin > 8g/dl, platelets > 75/nl, ANC > 1/nl, ALC > 0.3/nl, negative PCR for HBV, HCV, HEV and HIV; no active GvHD, no florid infection, no severe impairment of cardiac or pulmonary function. Leukapheresis was feasible in all patients and could be performed through peripheral venous access using the Spectra Optia™ device without any serious side effects. In total we performed 48 leukaphereses. 45 patients received a single apheresis and in three patients a later second apheresis was required due to infectious complications or electrolyte disturbance leading to a manufacturing failure. CAR T cell production was feasible for 44 of 45 patients. A mean blood volume of 11.8 (range 5.8-15) L was processed over a time of 238 (120-326) minutes. The leukapheresis product contained a mean of 11.8 x 10^9 (0.9-34.1 x 10^9) total nucleated cells and 4.9 x 10^9 (0.4 - 23.2 x 10^9) CD3+ T cells with a viability of 99.9 (99.6 - 100) % in a mean volume of 235 (136 - 310) ml with a hematocrit of 3 (1.1 - 7.4) %.

Conclusions: Leukapheresis was feasible in all patients in an out-patient setting. To harvest a sufficient number of lymphocytes for CART cell production, a minimum of 12 -15 L total blood volume should be processed in patients with an ANC 1-3/nl and ALC 0.3-1/nl. We established therefore a standardized procedure for the apheresis handling and developed a recommendation list for the timing of the medication before apheresis.

Disclosure: MS: Apogenix: Funding for collaborative research. Hexal: Financial support for research on biosimilars, travel grants. Kite: Financial support of educational activities and conference, travel grants. Co-PI of clinical trials on CAR-T cells. MSD: Ad board member, PI of clinical trials on letermovir. Novartis: Collaborative research grant. Co-PI of clinical trials on CAR-T cells. TolerogenixX: Co-Founder and shareholder.

AS: TolerogenixX: Co-Founder and shareholder, Mallinckrodt-Therakos: research grant, Jazz: travel grant.

PD: Advisory boards Novartis, Kite/Gilead

P086 NKG2D Car T Cells are not affected by Soluble NKG2D Ligands

Adrián Fernández1, Lucía Fernández1, Isabel Mirones2, Adela Escudero2,3, Leila Cardoso2,3, Gloria Esteso4, Raquel De Paz2, Joaquín Martínez-López5, Mar Valés4, Antonio Pérez-Martínez2,6

1CNIO, Madrid, Spain, 2Hospital Universitario La Paz, Madrid, Spain, 3INGEMM, Madrid, Spain, 4CNB, Madrid, Spain, 5Hospital 12 de Octubre, Madrid, Spain, 6Idipaz, Madrid, Spain

Background: NKG2D is an NK cell activating receptor that recognizes different stress-induced ligands (NKG2DL) that are overexpressed in different pediatric and adult tumors, while their expression in healthy tissues is rare. NKG2D-CAR T cells have shown potent antitumor effects against different types of cancer. However, tumor cells may develop immune escape strategies such as ligand release (sNKG2DL), whose effect on NKG2D-CAR has not been studied and could affect their clinical efficacy.

Methods: Clinical grade NKG2D-CAR memory (CD45RA-) T cells were produced by lentiviral transduction (NKG2D-41BB-CD3z, MOI = 2) and expansion in CliniMACS Prodigy. NKG2D-CAR memory T cells were infused in two patients excluded from CD19 CART cell trial with refractory relapse after hematopoietic stem cell transplantation. Patient#1 suffered from r/r biphenotypic ALL. She received two cycles of CAR T cells infusions. In the first cycle, a total of 3x107 cells/kg were infused into three weekly doses with no conditioning. In the second cycle, a total of 2x107 cells/kg were administered weekly into two doses after lymphodepleting conditioning with Cy/Flu and low dose bortezomib. Patient#2 suffered from r/r B-ALL and bronchopulmonary aspergillosis. She received a single dose of 1x107 cells/kg after lymphodepleting conditioning Cy/Flu and low dose bortezomib. sNKG2DL concentration was monitored in the patient´s sera by ELISA. The effects of sNKG2DL on NKG2D-CAR T cells (NKG2D expression, proliferation, cytokine release and cytotoxicity) were explored after exposition to different concentrations of sNKG2DL for 7 days, by flow cytometry, ELISA or LUMINEX, and a 2 hour-degranulation assay using K562 cells as target, respectively.

Results: NKG2D-CAR memory T cells were infused without severe side effects. Patient #1 showed no cytokine release syndrome (CRS), hypotension, pain or neurological events. At day +28 after the first infusion and one week after the first dose of the second cycle she developed pruriginous skin rash. Biopsy described toxicodermia versus grade I skin GvHD. Bone marrow evaluation described leukemia progression. Only 24 hours after infusion, patient #2 presented a respiratory impairment without fever and other CRS symptoms and required intensive care. Ten days after the CAR-T cell infusion, bone marrow aspiration revealed blast persistence and the family suggested to limit the therapeutic effort. Patient#2 showed an increase on sULBP2 compared to control. After NKG2D CAR T cells infusions, sNKG2DL trended to decrease in both patients. In vitro, physiological concentrations of sNKG2DL increased NKG2D-CAR expression. However, supra-physiological levels of sNKG2DL reduced NKG2D-CAR expression, increased cell proliferation, and stimulated TNF-a and IFN-g production, which was further increased in the presence of IL-2. High doses of sMICA decreased degranulation of NKG2D-CAR T cells, which was associated with receptor down-regulation. The effects of sNKG2DL were dose-dependent and slightly attenuated by IL-2.

Conclusions: NKG2D CAR memory T cells are essentially safe. Only supraphysiological levels of sNKG2DL caused NKG2D-CAR downmodulation, while normal levels induce cell proliferation and production of pro-inflammatory cytokines. Altogether these data suggest NKG2D CAR could be more resistant to the negative effects of sNKG2DL than endogenous NKG2D receptor. However, we did not observe a beneficial clinical effect in this advance situation.

Disclosure: The authors have nothing to disclose.

P087 Emerging Cytokine Release Syndrome is associated with Reduction of CD4+CD25high127dim T Regulatory Cells in Patients after Car T Cell Therapy

Christian R Schultze-Florey, Victoria Panagiota, Ivan Odak, Sultan Bektas, Tabea C Froehlich, Aleksandra Gladysz, Zhixiong Li, Gernot Beutel, Matthias Eder, Immo Prinz, Reinhold Foerster, Arnold Ganser, Christian Koenecke

Hannover Medical School, Hannover, Germany

Background: Chimeric antigen receptor (CAR) T cell therapy is often accompanied by potentially life-threatening cytokine release syndrome (CRS). The role of T regulatory cells (Tregs) during CRS remains to be elucidated. Here we prospectively investigated the Tregs population in patients with and without CRS after anti-CD19-CAR T Infusion.

Methods: The cohort consisted of 11 patients with relapsed or refractory transformed follicular lymphoma and diffuse large B cell lymphoma (DLBCL). All received anti-CD19-CAR T infusion (Tisagenlecleucel) after lymphodepletion with fludarabine and cyclophosphamide. All patients gave written informed consent to participate in the study. Patients were grouped based on emergence of CRS. Tregs were detected from peripheral blood via flow cytometry by staining for CD4+CD25+CD127dim- lymphocytes. To determine the absolute frequencies BD Trucount™ tubes were employed. Three time points were selected for analysis: baseline (d-1 - d+2 from Tisagenlecleucel infusion); 1 day prior or at the day of CRS diagnosis before start of CRS treatment (TP1, d+1 - d+6); after CRS clearance (TP2, d+3 - d+10). As control group served patients without CRS using comparable time points.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (15)

[Figure 1: Tregs frequencies in CRS vs no CRS patients.]

Results: Four patients met CRS criteria (Grade 1-4). On 3/4 CRS patients blood samples were available at all three time points and these were thus selected for analysis. Upon emergence of CRS (TP1) Tregs (measured in frequency of lymphocytes) showed a mean reduction of -46.91% compared to the baseline time point while the no-CRS controls increased their frequency by on average +10.57% (Figure 1A). Inter-group comparison at TP1 revealed differences of Tregs levels (0.87 vs. 3.10 % of lymphocytes) as well as in absolute Tregs count (1.79 Tregs/µl vs. 8.84 Tregs/µl, Figure 1B). Tregs frequencies in patients after CRS clearance (TP2) increased on average by 3.05-fold compared to TP1 while Tregs frequencies stayed stable in controls (Figure 1A). Based on this increase, Tregs frequencies at TP2 were similar to values of no-CRS patients. These findings are limited by the small patient number and in general low frequencies of Tregs early after CAR T infusion. Therefore, these pilot data need validation in a larger cohort.

Conclusions: In this prospective single center pilot study, blood samples of emerging CRS showed a reduction of Tregs frequencies and absolute numbers compared to no-CRS patients. After clearance of CRS, Tregs frequencies increased to values of no-CRS patients. Therefore, investigation of Treg frequencies as a predictive marker for CRS should be further investigated. However, future studies are needed to validate these findings in a larger cohort.

Disclosure: Nothing to declare.

P088 Excellent Proliferation and Persistence of Allogeneic CAR-T Cells Despite Immunosuppression with Cyclosporine A

Francis Ayuk, Boris Fehse, Dietlinde Janson, Carolina Berger, Kristoffer Riecken, Nicolaus Kröger

University Medical Center Hamburg, Hamburg, Germany

Background: Allogeneic CAR-T cell therapy bears the potential to combine graft-versus-malignancy effects and CAR-directed target killing, but comes with a considerable risk of graft-versus-host disease (GVHD). Animal studies indicate that the risk of GVHD after CAR-T infusion from an allogeneic donor may in part depend on the costimulatory domain used, first generation and 4-1BB-based CAR-T cells bearing an increased risk of GVHD [Gosh et al., 2017]. Interestingly, in the only report on donor-derived CAR-T cells with a 4-1BB costimulatory domain, both patients developed acute GVHD [Dai et al., 2015]. Use of immunosuppression to prevent GVHD after CAR-T cell infusion may prevent their expansion and efficacy. Here we present for the first time data on expansion and persistence of 4-1BB based CAR-T cells under immunosuppression with clinically relevant concentrations of cyclosporine A.

Methods: A 64-year old female with early relapse of follicular lymphoma grade 3A (day 65 after allogeneic hematopoietic stem cell transplantation, allo-HSCT) consented for compassionate-use treatment with CAR-T cells. CD19-CAR-T cells were manufactured from freshly collected allogeneic donor leukocytes using the CliniMACS Prodigy system and a lentiviral vector encoding the CD19-CAR containing a 4-1BB costimulatory domain.

The patient received lymphodepleting chemotherapy with cyclophosphamide and fludarabine and 1 x 106 /kg BW CAR-expressing cells on day 0 (3 months after allo-HSCT). Because the patient had history of acute GVHD, we maintained her on GVHD prophylaxis with cyclosporine A at a mean cyclosporine A trough level of 170 µg/l (range 122-206 µg/l) until day 21 after CAR-T cell infusion. With no evidence of active GVHD, cyclosporine A was tapered off from day +21 and stopped on day +56 after CAR-T cell infusion.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (16)

[Figure 1: CAR-T cell expansion and persistence]

Results: No CRS or ICANS were observed. Haematopoietic recovery was expectedly slow despite use of G-CSF as from day +21. Stable neutrophil counts > 1000/µl without further G-CSF support was attained on day 32, platelet count > 50.000/µl on day 150 after CAR-T cell infusion.

FDG-PET scan on day +30 revealed complete resolution of most of the lymphoma manifestations seen in the CT scan, but also showed new bone lesions in both sacrum and femur. A follow-up FDG-PET scan on day 120 showed regression of all lymphoma manifestations with only residual manifestations in the left sacrum.

Highest CAR-T cell numbers were measured on day +9 (50 CAR-T cells/µl) with continuous persistence of CAR-T cells up to the last examination 6 months after infusion (figure 1). While overall T cell reconstitution was well evident, B cell aplasia is persistent. Interestingly, the analysis of the CAR-T cells for activation and exhaustion markers revealed a decline in the fraction of effector and effector memory and a relative increase in central memory CD4+ CAR-T cells.

Conclusions: In conclusion, we for the first time present data on proliferation and persistence of allogeneic donor-derived 4-1BB based CAR-T cells under therapeutic levels of cyclosporine A. This indicates that for patients with early relapse after allo-HSCT with ongoing immunosuppression donor CAR-T cell therapy may be a feasible Treatment.

Disclosure: Nothing to declare.

P089 A French Biobanking Network to Create a Unique Collection of Samples of Patients Treated with car-t Cells

Emilie Robert1, Claire Fontenille1, Plotine Crochet1, Régis Peffault de Latour2, Jean-Hugues Dalle3, Boris Calmels4, Thierry Fest5, Loïc Ysebaert6, Catherine Thieblemont7, Cristina Castilla-Llorente8, Franck Morschhauser9, Steven Legouill10, Corinne Haioun11, Emmanuel Bachy12, Guillaume Cartron13, Roch Houot14

1CRYOSTEM, Marseille, France, 2Hôpital Saint Louis, AP-HP, Paris, France, 3Hôpital Robert Debré, AP-HP, Paris, France, 4Institut Paoli-Calmettes, Marseille, France, 5CHU Rennes, Rennes, France, 6Institut Universitaire Cancerologie Toulouse-Oncopole, Toulouse, France, 7Hôpital Saint-Louis, AP-HP, Paris, France, 8Institut Gustave Roussy, Villejuif, France, 9CHRU Lille, Lille, France, 10Hôpital Universitaire de Nantes, Nantes, France, 11Hôpital Universitaire Henri Mondor, AP-HP, Créteil, France, 12Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Pierre-Bénite, France, 13CHU Saint-Eloi, Montpellier, France, 14CHU Rennes - Pontchaillou, Rennes, France

Background: Even if Chimeric Antigen Receptor (CAR)-T cells therapies are a promising way to treat relapsed/refractory hematologic cancers, authorities face major issues regarding their economic impact, the evaluation of their efficiency and adverse effects. Since their launch the number of patients with CAR-T cells indication is increasing, as well as the number of hematological cancers likely to be treated. Nationwide collections of biological resources are warranted to develop scientific projects to monitor CAR-T cells treatments and improve our understanding of the underlying biological mechanisms.

In this context, a biobanking initiative resulted from the collaboration of two French consortia : CALYM, gathering together the LYSA (Lymphoma Study Association), LYSARC (Lymphoma Academic Research Organization) and 18 academic laboratories in the field of lymphoma, and CRYOSTEM, a collaborative biobanking network. After demonstrating respectively their ability to set up the first collection of viable cells from lymphoma patients (CeVi_collection) and the first European collection of biological resources dedicated to Hematopoietic Stem Cell Transplantation, CRYOSTEM and CALYM joined their expertise to constitute a biocollection from lymphoma patients receiving CAR-T cells.

Methods: The collaboration between CRYOSTEM and CALYM networks brings together hematological clinical units and biological resources centers (BRCs) to include patients, collect and process samples. Any patient suffering from lymphoma, justifying a CAR-T cells treatment is eligible for inclusion. Several types of samples are collected and derived pre- and post-CAR-T cells administration following a specific timeline. CALYM BRCs are in charge of the treatment and storage of lymph nodes and bone marrow samples in viable cells whereas CRYOSTEM BRCs enrich this collection by processing blood samples in viable cells and plasma, and also stools and urines. Annotated biological samples are centralized in CALYM database.

Results: In less than one year, CRYOSTEM and CALYM set up the organizational and regulatory framework of the first collection of samples and associated data dedicated to CAR-T cells treated patients:

  • Constitution of governing bodies including representatives from both organizations;

  • Identification of the 9 clinical units and BRCs involved in the protocol;

  • Practices harmonization and standardization regarding samples and protocols;

  • Establishment of sampling kinetics integrated to patients’ care. Paired with lymph nodes, 8 blood sampling points are planned from apheresis to 6 months post-injection and/or at relapse;

  • Estimation of the collecting rate of each sampling point according treatment failure and mortality rate;

  • Evaluation of the annual number of inclusions.

First inclusions are planned in January 2020.

Conclusions: With the creation of the first biobank focused on CAR-T cells treated patients, the CALYM-CRYOSTEM collaboration opens new research perspectives by providing access to raw material. This approach would impact CAR-T cells treatments by providing a large amount of post-infusion data, contributing to consolidating knowledge on this recent cell-based therapeutic approach.

This initiative, focused on lymphoma, sets up the bases of the constitution of new type of collection integrating complementary expertise and actors in CAR-T care and research. It will constitute a proof of concept for other initiatives in this field, independently of the initial hematological disease.

Clinical Trial Registry: Non applicable

Disclosure: Any conflict of interest

P090 CAR T Cell Therapy Directed against CD19 in Patients with B-cell Lymphoma after an Allogeneic Hematopoietic Stem Cell Transplantation (AlloHCT) is Feasible and Safe

Maria-Luisa Schubert1, Sascha Dietrich1, Anita Schmitt1, Petra Pavel2, Alexander Kunz1, Andrea Bondong1, Mandy Wegner1, Peter Stadtherr1, Susanne Jung3, Stephan Stilgenbauer4, Anthony Ho1, Carsten Müller-Tidow1, Michael Schmitt1, Peter Dreger1

1University Hospital Heidelberg, Heidelberg, Germany, 2German Red Cross Blood Service Baden-Wuerttemberg-Hessen, Heidelberg, Germany, 3Diakonie Hospital Stuttgart, Stuttgart, Germany, 4Saarland University Medical Center, Homburg, Germany

Background: CD19-directed chimeric antigen receptor T cells (CARTs) have been successfully used in patients with acute lymphoblastic leukaemia (ALL) after a preceding allogeneic stem cell transplantation (alloHCT). However, data on feasibility and outcome of CARTs in patients previously allotransplanted for B-cell lymphoma are lacking. Here, we report our institutional experience in this setting.

Methods: Course and outcome of allo-grafted patients treated with CD19 CARTs for B-cell lymphoma between October 2018 and November 2019 were studied in a single-center retrospective analysis. CARTs were administered either as third-generation CARTs within the Heidelberg CART 1 (HD-CAR-1) clinical trial (Eudra-CT No. 2016-0048; NCT03676504), or with commercially manufactured second-generation CARTs Axicabtagene Ciloleucel (Axi-cel, Gilead). Number of infused CARTs ranged from 1x106-2x107/m2 (HD-CAR-1) or were within the label-specified range (Axi-cel).

Results: 10 CART dosings using recipient leukapheresis products have been administered to 8 patients: 4 patients (2 mantle cell lymphoma (MCL), 2 CLL) received 6 infusions with HD-CAR-1 CARTs. 4 patients (all with DLBCL) received 4 infusions with Axi-cel. Lymphodepleting chemotherapy with flu/cy (30/500 mg/m2/d for 3 days) was administered to all patients prior to CART infusion. All 8 patients were male with a median age of 57 (27-70) years. A median of 4 (3-11) treatment lines had been administered during 5.8 (1.5-12.5) years from diagnosis. Median time from alloHCT to CART treatment was 2.4 (1.0-8.2) years. AlloHCT had been performed from matched related (MRD) (3), matched unrelated (MUD) (4), or haplo (1) donors after myeloablative conditioning. Acute and chronic GvHD after alloHCT had been observed in 2 and 6 patients, respectively. No patient had active GvHD or was under immune suppression at the time of leukapheresis and all patients had active disease. CART treatment was well tolerated with higher grade CRS and ICANS each being observed after 1 of 10 evaluable dosings. Patients had complete resolution of CRS and ICANS following administration of tocilizumab and steroids, respectively. A single patient had cutaneous and hepatic reactions suspicious of chronic GVHD early after dosing, whereas all other dosings were not accompanied by GVHD. CARTs were detectable in the peripheral blood (PB) in all but one patient. The patient developing ICANS displayed the highest CART frequency in the PB. With a median follow-up of 108 (18-314) days, all patients are alive with an overall best response rate of 88%. 3 of 7 evaluable patients achieved ongoing CRs. B cell aplasia and cytopenia were observed in all patients following CART dosings. B cell aplasia is ongoing in 8 instances and long-term (>1 month) leukopenia and thrombocytopenia were observed following 8 and 7 dosings, respectively.

Conclusions: Therapy with CARTs manufactured from recipient-derived leukapheresis products after prior alloHCT was feasible, safe and efficient. Therefore, CARTs as salvage treatment for patients with B-cell lymphoma relapsing after alloHCT constitute a justifiable treatment option. Cytopenia as a result of multiple myelotoxic treatments needs to be carefully monitored.

Disclosure: Dreger: AbbVie, AstraZeneca, Gilead, Janssen, Novartis, Riemser, Roche: Consultancy; AbbVie, Gilead, Novartis, Riemser, Roche: Speakers Bureau; Neovii, Riemser: Research Funding; MSD: Membership on an entity´s Board of Directors or advisory committees, Other: Sponsoring of Symposia. Schmitt: Therakos Mallinckrodt: Other: Financial Support. Sellner: Takeda: Employment. Müller-Tidow: MSD: Membership on an entity´s Board of Directors or advisory committees. Schmitt:Therakos Mallinckrodt: Other: Financial Support; MSD: Membership on an entity´s Board of Directors or advisory committees, Other: Sponsoring of Symposia. Stilgenbauer: Pharmacyclics: Other: Travel support; Gilead, Celgene, Amgen, AbbVie, Novartis, AstraZeneca, Hoffmann La-Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau.

P091 Lymphocyte Collection for Generation of CAR T-cells in Pediatric Patients: A Single Center Experience

Giovanna Del Principe1, Giovanna Leone1, Annalisa Ruggeri1, Simone Biagini1, Elia Girolami1, Stefania Lazzaro1, Antonella Meschini1, Francesca Del Bufalo1, Manuel Broglia1, David Malaspina1, Katia Feri1, Federica Galaverna1, Pietro Merli1, Valentina Bertaina1, Mattia Algeri1, Mauro Montanari1, Andrea Onetti Muda1,2, Giuseppina Li Pira1, Franco Locatelli1,3

1Bambino Gesù Children’s Hospital, Rome, Italy, 2Campus Bio-Medico Univerisity, Rome, Italy, 3Sapienza University of Rome, Rome, Italy

Background: Chimeric antigen receptor (CAR) T-cell therapy is a novel anti-tumor strategy in which autologous T-cells are engineered to express a CAR construct targeting an antigen expressed on membrane malignant cells. The CAR T-cell manufacturing process consists of different steps performed by different units, namely apheresis, cell therapy laboratory and the clinical unit. The collection of patient’s T-cells by the apheresis unit is the first step, followed by the characterization and manipulation of the cell product.

Herein, we report on 70 apheresis procedures performed on children and young adults with hematological and non-hematological diseases who underwent PBMC purification and cryopreservation for subsequent CAR T-cell production for academic trials at our institution.

Methods: Seventy collections were performed between January 2017 and November 2019; 51 patients were males, 19 females, median age being 9 years (range, 3-25) and median body weight (BW) 24 kg (range, 11-106). Indication for CAR T-cell production was refractory/relapsed Acute Lymphoblastic Leukemia (ALL, n=27), non-Hodgkin’s lymphoma (NHL, n=6) or Neuroblastoma (NBL, n=37). Leukapheresis was performed by Spectra Optia using continuous and discontinuous mononuclear cell protocol (CMNC vs MNC), with a collection target >4x10*9 mononuclear cells (MC). In 37/70 (53%) cases, patients had a central venous double lumen catheter (CVC), 17/70 (24%) were collected through peripheral venous accesses (VP) and 16/70 (23%) using both approaches (CVC+VP). Sodium heparin and Acid Citrate Dextrose Solution-A (ACD-A) were used in combination as anticoagulants. After apheresis, a density gradient PBMC purification using the Sepax 2 device was performed and the MCs were eventually cryopreserved.

Results: The median lymphocyte counts before apheresis were 1080/ul (200-4070). Out of 70 collections, 34/70 were performed using MNC (49%) and 36/70 using CMNC (51%). For all patients, the median total blood volume (TBV) processed was 2.1L (0.59-4.3), while for patients < 15kg (11/70, 16%) the processed TBV was 2.7L (1.6-4.3). Apheresis bags contained a median of 5.2x10*9 nucleated cells (1.5-15.4). Lymphocyte collection efficiency (lympho-CE) had a median value of 68% (range, 24-100). 27 products from ALL patients, 6 products from NHL patients and 37 products from NBL patients underwent a density gradient purification for PBMC enrichment. For ALL and NHL patients, median recovery for MNC was 76% (61-93) and median red blood (RBC) depletion was 81% (45-94). Total MNC and CD3 cells were 2.75x10*9 (0.84-8.26) and 1.33x10*9 (0.58-2.74) respectively. For NBL patients, median recovery for MNC was 73% (54-89) and RBC depletion was 79% (64-96). Total MNC and CD3 cells were 2.7x10*9 (1.0-6.0) and 1.0 (0.4-8.0).

Conclusions: Sufficient numbers of cells can be obtained from pediatric patients with BW < 15 kg, with a median value of processed TBV of 2.7L (1.6-4.3), provided that their lymphocyte counts are >900/ul. All patients reached the target cells in a single apheresis, including 2 patients with lympho-CE < 30%. In 56/70 (80%) of collections, lympho-CE was ≥50%.

Density gradient purification with the Sepax device is helpful to remove a fraction of RBC, allowing subsequent cryopreservation of pure products in which CD3+ cell concentration is higher with respect to other cellular components.

Disclosure: Nothing to declare.

P092 Baseline Hypoalbuminemia does not appear to be an Adverse Prognostic Factor in Patients with Relapse/Refractory B-cell Lymphomas Treated with Axicabtagene Ciloleucel (Axi-cel)

Megan Melody1, Sangeetha Gandhi2, Zaid Abdel Rahman1, Paula Lengerke Diaz3, Nicole Gannon1, Allison Rosenthal3, Taun Truong2, Mattia Novo2,4, Eva Brandes2, Gina Lange2, Breana Etsby2, Patrick Johnston2, Steve Ansell2, N. Nora Bennani2, Jonas Paludo2, Jose Villasboas Bisneto2, Ernesto Ayala1, Han W. Tun1, Hemant Murthy1, Vivek Roy1, James Foran1, Januario Castro3, Yi Lin2, Mohamed Kharfan-Dabaja1

1Mayo Clinic, Jacksonville, FL, United States, 2Mayo Clinic, Rochester, MN, United States, 3Mayo Clinic, Phoenix, AZ, United States, 4Azienda Ospedaliera Universitaria, Citta della Salute e della Scienza di Torino, Torino, Italy

Background: Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy that is approved for treatment of relapsed/refractory (R/R) large B-cell lymphoma and is associated with high response rates and durable remissions. Recent data show that axi-cel is effective across various adverse prognostic features, namely cell of origin, disease bulkiness, and extranodal disease, among others. Hypoalbuminemia is a known adverse prognostic factor in lymphomas. Yet, it is unknown if axi-cel overcomes the adverse prognostic feature of hypoalbuminemia in R/R large B-cell or transformed follicular lymphoma.

Methods: We conducted a retrospective analysis of patients treated with axi-cel across three Mayo Clinic campuses (Rochester, Jacksonville, and Phoenix) from 06/01/2016 until 12/01/2019. The primary objective of this analysis was to assess the correlation of hypoalbuminemia defined as a serum albumin levels ≤ 3.5 g/dL on day 0, prior to infusion on outcomes after axi-cel therapy.

Results: A total of 69 (male=48, 70%) patients (pts), median age of 53 (24-74) years received axi-cel. The median number of prior lines of therapy was 3 (2-8) (Table 1). Two pts had no available serum albumin levels at time of axi-cel infusion. Thirteen (19%) of 67 pts had hypoalbuminemia (median= 3.3 g/dL (range 2.5-3.5)) and the median follow-up of survivors in this group was 6.7 (1.7-17.8) months. The best overall response rate (ORR) and complete remission (CR) rates in these pts were 62% and 46%, respectively. One (8%) patient had stable disease and 4 (31%) had disease progression. On the other hand, 54 (81%) pts had a normal serum albumin (defined as > 3.5 g/dL) level (median=4.1 (range 3.6-5.1) g/dL) and the median follow up for survivors in this group was 5.4 (1.0-30.9) months. The best objective response rate (ORR) and complete remission (CR) rates in these pts were 81% and 41%, respectively. There was no difference in 1-year OS between the group with hypoalbuminemia (64% (95%CI=30-99%)) and the group with normal serum albumin level (57% (95%CI=34-79%), p=0.88. All grades cytokine release syndrome (CRS) was diagnosed in all 13 pts with hypoalbuminemia (100%) and in 48 of 54 (89%) pts without hypoalbuminemia. There was no difference in the median duration of CRS between pts with or without hypoalbuminemia [5 (1-11) days vs 5 (1-19) days, p=0.84]. Neurotoxicity (all grades) was observed in 8 (62%) pts with hypoalbuminemia compared 27 (50%) with normal albumin levels. There was no statistically significant difference in median duration of neurotoxicity between pts with hypoalbuminemia and those with normal baseline albumin levels [9 (range 1-56) days vs. 3 (range 0-25) days, p= 0.07].

Conclusions: Hypoalbuminemia does not have a significant impact on the outcomes of axi-cel therapy, including OS or the incidence of CRS or neurotoxicity. Large multicenter clinical trials are needed to validate these findings.

Clinical Trial Registry: None

Disclosure: Lin, Yi: Research funding: Janssen, Merck, Kite/Gilead, Celgene, BlueBird Bio, Takeda

Consulting: Janssen, Legend BioTech, JUNO, Celgene, BlueBird Bio, Kite/Gilead, Novartis, Gamida Cells, AlloGene.

DSMB: Sorrento

Steering committee: Celgene, Janssen, Legend Biotech

P093 Factors Predicting CD3+ Collection for the Production of Chimeric Antigen Receptor (CAR) T Cells

Silvia Monsalvo, Gonzalo Balsera, Gillen Oarbeascoa, Ana Perez-Corral, Mariana Bastos, Nieves Dorado, Rebeca Bailen, Ariana Ortuzar, Maria Reyes Martin, Maria Consuelo Vega, Carmen Granado, Carmen Falero, Nuria Ruano, Cristina Muñoz, Mi Kwon, Jose Luis Diez-Martin, Javier Anguita

Hospital Gregorio Marañón, Madrid, Spain

Background: Chimeric antigen receptor (CAR) T cells are a promising new immunotherapy. However, the challenges of collecting CD3+ lymphocytes in this population of patients have not been well-characterized. The aims of the study were to evaluate the feasibility of collection adequate numbers of CD3+ cells, analyze the rate of adverse events and to identify the variables that can predict inadequate collections.

Methods: We prospectively study the apheresis for lymphocyte collections (ALC) from patients in real live for CARs from May-19 to November-19. Collections were performed on the same Cobe Optia device, at hematocrit of 1 to 2% and collection flow rate of 0.8 mL/min. All patients had Hickman central venous catheters placed before the procedure, and received intravenous calcium gluconate as per SOP. The product goal was a target of 1 x 109 CD3+ cells.

Results: 14 ALC were performed. Median age 59.5 years (28-69). 57%(n=8) were male. 57%(n=8) were sent for the production of axicabtagene ciloleucel, 43% for tisagenlecleucel. Diagnosis was 100% lymphoma, median of 16.4 months from the diagnosis to ALC (6-48.8). Ann arbor stage was 3 in 2 patients(14%), 4 in 11 patients(79%). 50%(n=7) received 3 or more prior lines of treatment. Potential treatment affecting the collection prior apheresis: 36%(n=5) purine nucleoside antimetabolites, 21% (n=3) received IMiDs, 50%(n=7) Autologous Stem cell transplant and 36% (n=5) radiotherapy. Last treatment before ALC was systemic chemotherapy in 7 patients (57%), radiotherapy 4 patients (29%), immunotherapy 2 patients (14%). Median of 45 days from the treatment to ALC (15-1000).The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (17)

[Correlation between pre-apheresis CD3+ (cells/µL) neutrophils and CD3+ yield]

Pre-apheresis laboratory testing were : median leucocyte(x 106/mL) of 4 (1-14.4), median hematocrit (%) 30.2 (25-41), median platelets (x106/mL) 112 (25-345), median neutrophils (%) 63.5 (34.3-86), median lymphocyte (%) 20.2 (30.8-50), median NK (%) 3.2 (0.3-8.7), median (%) CD19+ 0(0-4.8), median CD3+ (cells/µL) 460 (147-2770), median CD3+(%) 12.2(4-38) of which median CD4+(%) 37.25(10-72) and CD8+(%) 55.9 (24.5-85)

Apheresis parameters were: median of 12 liters processed (5-15), collection efficiency median (%) 52.9 (40.9-75.5). One patient developed symptomatic hypotension during the procedure, other complications related to hypocalcemia including paresthesias were managed in the apheresis unit.

Apheresis collection yields from 13 products were: median volume of 199 mL (86-240), median hematocrit(%) 3.2 (1.8-17.7), median platelets(x106/mL) 811(255-3784), median volume ACD-A(mL) 22(10-31), cell concentration (cellsx106/mL) 58.9 (12.7-247.7), median total nucleated cells (x109) 9.9 (2.8-52.5), median mononuclear cells(x106/mL) 51.3(12.6-242.7). Median(%) CD3+ of CD45+ was 53(23-83.5) with a median total number of CD3+ (x109) of 5.2 (1.1-17.3).

Univariate analysis showed that higher pre-apheresis CD3+ (cells/µL) was significantly correlated with CD3+ total collected cells in the apheresis product. Thus, there is an association with higher proportion of neutrophils in peripheral blood with lower pre-apheresis CD3+ counts (figure1).

Conclusions: In most patients undergoing CART cell therapy, leukapheresis is well-tolerated and adequate numbers of CD3+ lymphocytes are collected. A personalized approach to the collection process is the essential first step for CART cell immunotherapy. However, further studies of larger cohorts of patients including new variables are necessary to confirm this findings to ensure that all patients can have sufficient cells for manufacturing.

Disclosure: Nothing to declare.

P094 Cytopenias after Tisagenlecleucel in Paediatric/young Adult Patients with Refractory/relapse b-cell Acute Lymphoblastic Leukaemia (R/R B-all): A real-life Single-centre Experience

Ignacio Gómez-Centurión1, Saskia Burridge2, Juliana Silva2, Arina Lazareva2, María Gabelli2, Oana Mirci-Danicar2, Giovanna Lucchini2, Robert Chiesa2, Kanchan Rao2, Sujith Samarasinghe2, Paul Veys2, Ajay Vora2, Persis Amrolia2, Sara Ghorashian2

1Hospital General Universitario Gregorio Marañón, Madrid, Spain, 2Great Ormond Street Hospital for Children, London, United Kingdom

Background: Tisagenlecleucel (KymriahTM) is a CD19-targeted CAR-T cell therapy approved for r/r B-ALL in paediatric/young-adult patients. Cytopenias following CAR-T cells are relatively common across multiple studies1 including those targeting CD19 and CD22 and are therefore not antigen-specific. The incidence and clinical impact of persistent or recurrent cytopenias has been under-recognized in clinical studies to date and the aetiology is as yet unclear. The objective of this study is to describe cytopenias and related complications in paediatric/young-adult patients with r/r B-ALL treated with Tisagenlecleucel.

[1] Jacoby et al. 10.1038/s41409-019-0487-3

Methods: We retrospectively analyzed 12 consecutive patients with r/r B-ALL treated with Tisagenlecleucel between January 2019 and November 2019 in a single centre. Patients received lymphodepletion with fludarabine (120 mg/m2) and cyclophosphamide (1000 mg/m2). Cytopenias were graded according to CTCAE V-5.0. Persistent cytopenias were defined as grade 2-4 cytopenias after day-28. Recurrent cytopenias were defined as new-onset grade 3-4 cytopenias after day-28 when and after achieving normal counts on day-28. Cytopenias were considered resolved when grade 1 or normal counts were achieved.

Results: Patient characteristics are summarised in Table 1. Nine patients were diagnosed with relapsed B-ALL after HSCT, 2 had relapsed B-ALL with a contraindication for HSCT and 1 had primary refractory disease. With a median follow-up of 4 months (range 1-10) after CAR-T cell infusion, MRD was negative in 11 patients (92%), B cell aplasia was persistent in 10 (83%) and 1 (8%) had a relapse and died.

Eight patients (67%) presented with grade 2-4 cytopenias before lymphodepletion.

Before day-28, all patients developed grade 2-4 anaemia (9=75% grade 3-4), 8 patients (67%) developed grade 2-4 thrombocytopenia (6=50% grade 3-4), and all patients developed grade 3-4 neutropenia.

Four patients (33%) had persistent grade 2-4 anaemia, 2 (17%) grade 3-4. Five (42%) had persistent thrombocytopenia, all grade 3-4. Seven (58%) had persistent neutropenia, all grade 3-4. Two patients (17%) with normal counts on day-28, developed recurrent grade 3-4 neutropenia after day-28.

Secondary causes of cytopenias were excluded. Among patients with persistent cytopenias, 4 (50%) had a hypocellular marrow on histology of the BM trephine.

Eight patients (67%) received at least one RBC transfusion before day-28, and 2 (17%) after day-28. Three patients (25%) received at least one platelet transfusion before day-28, and 4 (33%) after day-28. Seven patients (58%) received at least one Filgrastim dose after day-28. Eight documented infections were diagnosed, 3 of them after day-28, with 0% of infection-related mortality.

At last follow-up, anaemia was resolved in all patients, 2 (17%) had ongoing thrombocytopenia, (1 with platelet transfusion dependence), and 3 (25%) ongoing neutropenia (1 with Filgrastim dependence).

Conclusions: Cytopenias were frequent in patients treated with Tisagenlecleucel. Whilst early cytopenias are expected due to lymphodepletion, mechanisms of persistent and recurrent cytopenias are unclear and might be related to CAR-T cells persistence. More studies are needed to determine etiology and risk factors for persistent cytopenias. Cytopenias are of relevance in terms of increased requirement for supportive care, however, in our cohort, were not associated with significant or persisting complications.

Disclosure: Nothing to declare.

P095 The risk of Hepatitis B Reactivation is controllable in B-cell Malignancies Patients with Concomitant Hepatitis B Virus Infection after Chimeric Antigen Receptor T Cell Therapy

Fang Ni1,2, Yongxian Hu1, Alex Hong Chang3, He Huang1

1The First Affiliated Hospital, Zhejiang University, Hangzhou, China, 2Zhejiang University, Hangzhou, China, 3Shanghai YaKe Biotechnology Ltd, Shanghai, Shanghai, China

Background: Chimeric antigen receptor- modified (CAR) T-cell immunotherapy is a novel promising therapy for relapsed/refractory B cell malignancies. Prolonged B- cell aplasia is a common and expected toxicity after receiving CAR-T cell treatment. However, the risk of HBV reactivation after CAR-T cell therapy is still unknown. We summarized the risk of HBV reactivation in R/R B-cell Malignancies patients with Concomitant Hepatitis B Virus infection after Chimeric Antigen Receptor T Cell Therapy at our hospital.

Methods: Patients with R/R B-cell lymphoma, B-ALL and Multiple Myeloma who received CAR-T cell treatment in four clinical trials (ChiCTR-ORN-16008948, ChiCTR-OIC-17011310, ChiCTR1800015575, ChiCTR1800017404) in our center were retrospectively analyzed. All patients were screened for hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs), antigen antibody to hepatitis B core antigen (anti-HBc) and HBV DNA copy numbers before and after CAR-T cell treatment. Those with positive HBsAg were eligible for this retrospective study.

Results: Between December 2017 and October 2019, 10 patients with relapsed or refractory B cell malignancies and concomitant HBV infection who were treated with CAR-T cells were included in this study. The median age was 50 years (range: 39-67 years), with 60% were male. Details are summarized in table I. All of the 10 patients with chronic HBV infection received prophylactic entecavir treatment. And at the time of CAR-T cell infusion, HBV DNA levels of all patients were lower than the normal limit. With median follow-up 7.77 months (range:1.43-23.8 months) from CAR-T cell infusion, 2patients (patient 9 and patient 10) had transient HBV reactivation. However, the HBV DNA copy numbers came back to lower than the normal limit with the entecavir and Adefovir treatment. All patients reminded on prophylactic NAT by the time of last follow-up. Figure1 showed the Time points of HBV detection and response after CAR-T cell treatment.

Conclusions: our results showed that CAR-T cell treatment could be safely administered in patients with Concomitant Hepatitis B Virus infection. Considering the small group sample size and retrospectively analysis, the risk of HBV reactivation with prophylactic entecavir treatment after CAR-T cell treatment should be further evaluated in large and prospective studies.

Patient139 yMale24 cycles treatment before CAR-T therapyDLBCLCD19-CD226.44*10^6/kgNo HBV reactivation
Patient260 yFemale6DLBCLCD225.85*10^6/kgNo HBV reactivation
Patient355 yMale12MMBCMA2.64*10^6/kgNo HBV reactivation
Patient449 yMale6Aggressive B cell lymphomaCD19-CD2210.28*10^6/kgNo HBV reactivation
Patient543 yFemale18DLBCLCD19-CD225.72*10^6/kgNo HBV reactivation
Patient647yMale5B-ALLCD195.6*10^6/kgNo HBV reactivation
Patient767 yMale7MMBCMA3.49*10^6/kgNo HBV reactivation
Patient850 yFemale9MMBCMA5.59*10^6/kgNo HBV reactivation
Patient950 yFemale6Lymphoblast lymphomaCD19-CD228.04*10^6/kgYes, and recovered after entecavir treatment
Patient1053 yMale6MMBCMA5.1*10^6/kgYes, and recovered after entecavir treatment

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[Patient clinical characteristics before and after chimeric antigen receptor T cell therapy]

The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (18)

[Figure1. Time points of HBV detection and response after CAR-T cell treatment]

Clinical Trial Registry:

ChiCTR-ORN-16008948

ChiCTR-OIC-17011310

ChiCTR1800015575

ChiCTR1800017404

The website is http://www.chictr.org.cn

Disclosure:

Nothing to declare.

P096 Cumulative Rituximab Exposure Prior to Axicabtagene Ciloleucel is not associated with Persistent Leukopenia and Thrombocytopenia at Day +90 Post Infusion

Madiha Iqbal1, Sangeetha Gandhi2, Abdullah Alselah2, Muhamad Alhaj Moustafa1, Ernesto Ayala1, Hemant Murthy1, Allison Rosenthal3, Jilan Kubusek2, Justin Haynes2, Tuan Troung2, Patrick Johnston2, Stephen Ansell2, Nora Bennani2, Jonas Paludo2, Jose Villasboas Bisneto4, Breana Estby2, Eva Brandes2, Gina Lange2, Januario Castro3, Yi Lin2, Mohamed Kharfan-Dabaja1

1Mayo Clinic, Jacksonville, FL, United States, 2Mayo Clinic, Rochester, MN, United States, 3Mayo Clinic, Phoenix, AZ, United States, 4Mayo Clinic, Rochester, FL, United States

Background: Cytopenias occur frequently after axicabtagene ciloleucel (axi-cel), a recently approved anti-CD19 CAR-T cell therapy. The direct cause(s) of cytopenia (s) remains elusive. Rituximab has been associated with delayed onsent cytopenia in patients with non-Hodgkin lymphoma. Here, we investigate the impact of various patient- and pre-CAR-T treatment related factors including cumulative rituximab exposure, prior lines of treatment and prior auto-HCT on the persistence of cytopenia (s) in the setting of axi-cel.

Methods: We conducted a retrospective analysis of patients treated with axi-cel across three Mayo Clinic campuses (Rochester, Jacksonville, and Phoenix) from June 2016 until October 2019. Five patients received axi-cel in a clinical trial. The primary objective of this analysis was to identify factors associated with persistent cytopenias (leukopenia and thrombocytopenia) at day +90 in axi-cel recipients. Leukopenia was defined as less than 3 x109/L and thrombocytopenia as a less than 100 x109/L. Univariate analysis was used to analyze predictors and outcomes.

Results: A total of 57 patients, males (n=41, 72%), who had received a median of 3 (2-8) prior lines of therapy received axi-cel. Seventy three percent of patients (33/45, 12 patients had missing data) experienced at least a grade 1 cytopenia per CTCAE v5.0 at day+90. Twenty-four patients had failed a prior autologous transplant. The median number of prior rituximab doses was 8 (2-19). Pertaining to day +90 persistent leukopenia, age (≤ 52 vs. > 52 years, p=0.75), gender (p=0.72), number of prior therapies (p=0.80), a prior auto-HCT (p=0.66), and cumulative doses of rituximab (p=0.51) were not significant variables. None of these factors was predictive of persistent neutropenia (defined as less than 1.5 x109/L) by day +90 post axi-cel. Pertaining to day +90 persistent thrombocytopenia, age (≤ 52 vs. > 52 years, p=0.3), gender (p=0.1), number of prior therapies (p=0.06), a prior auto-HCT (p=0.54), and cumulative doses of rituximab (p=0.06) were not significant variables.

Conclusions: Our analysis did not identify rituximab or any other patient- or pre-CAR-treatment related factors to be associated with persistence of leukopenia and thrombocytopenia at day +90 post axi-cel.

CharacteristicTotal number of patients = 57
Age (years-range)52 (25-68)
Gender (male)41 (72%)
HistologyDLBCL:32(56%);PMBCL:6(11%);TFL: 11(19%);HGBCL:8(14%)
Prior lines of treatment (Median, range)3 (2-8)
Autologous Stem Cell Transplant24 (42%)
Number of Rituximab Doses (Median, range)8 (2-19)
Time from initial diagnosis to CAR-T (Median, range)13.7 months (3.2-193.6)

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[Table 1]

Disclosure: YL declare.d the following conflicts of interest:

Research funding: Janssen, Merck, Kite/Gilead, Celgene, BlueBird Bio, Takeda

Consulting: Janssen, Legend BioTech, JUNO, Celgene, BlueBird Bio, Kite/Gilead, Novartis, Gamida Cells, AlloGene.

DSMB: Sorrento

Steering committee: Celgene, Janssen, Legend Biotech

MAK-D: consultancy for Daiichi Sankyo

Remaining authors disclose no relevant conflicts of interest.

P097 Comprehensive Immune Cell Monitoring Reveals an Altered Lymphocyte Subset Phenotype in Patients not Responding to Tisagenlecleucel One Month Post Infusion

Christian R Schultze-Florey, Victoria Panagiota, Ivan Odak, Sultan Bektas, Tabea C Froehlich, Aleksandra Gladysz, Zhixiong Li, Gernot Beutel, Matthias Eder, Immo Prinz, Reinhold Foerster, Arnold Ganser, Christian Koenecke

Hannover Medical School, Hannover, Germany

Background: Reconstitution of lymphocyte subsets following lymphodepletion and chimeric antigen receptor (CAR) T cell infusion is pivotal for pathogen control. Moreover, lymphocyte subsets are thought to support CAR T antitumor activity. In this prospective single center pilot study we aim to investigate whether failure of anti-CD19-CAR T cell (Tisagenlecleucel) response one month post infusion is associated with a specific lymphocyte subset phenotype.

Methods: Blood samples of eleven patients with relapsed or refractory transformed follicular lymphoma and diffuse large B cell lymphoma (DLBCL) were examined by multi-color flow cytometry. Following lymphodepletion with fludarabine and cyclophosphamide, all patients received Tisagenlecleucel. The institutional review board approved the study and all patients gave written informed consent for prospective immune cell monitoring. Lymphocyte subsets were detected from peripheral blood using a 10-color antibody mix for T, B, and NK cell subsets as well as activation markers via flow cytometry. For determination of absolute frequencies BD Trucount™ tubes were used. Treatment response to anti-CD19-CAR T therapy was assessed via PET-CT one month post infusion.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (19)

[Figure 1: Analysis of lymphocyte subsets in responders (R) vs. non-responders (NR) at day +28.]

Results: Blood samples and PET-CT data were available on 9 out of 11 patients one month post infusion of Tisagenleclucel. Disease progression or no response to therapy was observed in 3 patients, termed non-responders (NR). The remaining 6 patients, termed responders (R), all showed reduced PET activity, with two (33%) achieving complete metabolic remission and four (66%) achieving partial metabolic remission. We compared different lymphocyte subsets in non-resonders vs. responders on day +28 (range 11-34). Interestingly, non-responders displayed higher relative frequencies and absolute numbers of CD8+ and CD3+CD56+ cells and fewer CD3-CD56+ cells compared to responders, albeit lacking statistical significance, likely due to the small sample size (Figure 1A and B). Moreover, CD4:CD8 ratio was markedly lower in non-responders (0.53 vs. 2.73), implying a shift in immune response. Further analysis of activation markers in conventional CD4+ (CD4conv) and CD8+ cells revealed a trend towards decreased central memory populations in non-responders (Figure 1C and D).

Conclusions: Immune cell monitoring of lymphocyte subsets in CAR T cell patients may provide important insights in immune function supporting CAR T cell activity. In this prospective single center pilot study we describe an altered lymphocyte subset phenotype in patients failing to respond to Tisagenlecleucel. The phenotype consisted of a reduced CD4:CD8 ratio, lower CD3-CD56+ frequencies and central memory populations together with higher CD8+ and CD3+CD56+ populations. However, these data are limited by the small cohort size and warrant further validation in a larger cohort.

Disclosure: Nothing to declare.

P098 Neurotoxicity associated with CAR T Cell Therapy: Neurological Management and work-up of 11 Adult Patients

Nora Moehn, Viktoria Bonda, Mike P. Wattjes, Victoria Panagiota, Sascha David, Gernot Beutel, Matthias Eder, Martin Stangel, Arnold Ganser, Christian Koenecke, Thomas Skripuletz

Medizinische Hochschule Hannover, Hannover, Germany

Background: Treatment with CD19 chimeric antigen receptor (CAR) T cells represents a novel treatment approach for patients with relapsed or refractory diffuse large B cell lymphoma (r/rDLBCL) or B-lineage acute lymphoblastic leukemia (ALL). However, impressive therapeutic response rates are often accompanied by specific and severe toxicities. Besides the common cytokine release syndrome (CRS) which is characterized by fever, hypotension, hypoxia, and in more severe cases multisystem organ dysfunction, specific neurotoxicity termed immune effector cell-associated neurotoxicity syndrome (ICANS) has been observed as well and is treated as a separate entity with distinct timing and treatment requirements. Although symptoms can be more diverse than those of CRS, many patients with neurotoxicity show specific clinical features with expressive aphasia being one of the most characteristic ones.

Methods: Eleven r/rDLBCL patients have been treated with Tisagenlecleucel at Hannover Medical School between April 2019 and November 2019. All patients received an extensive neurological examination prior to CAR T cell infusion. This included clinical examination, handwriting sample, cognitive testing (Montreal-Cognitive-Assessment (MoCA)), brain magnetic resonance imaging (MRI), electroencephalogram (EEG), electroneurography (ENG), and analysis of cerebrospinal fluid (CSF) in 8/11 patients. After CAR T cell infusion, patients were neurologically examined for 10 consecutive days. Up to 4 weeks following infusion, we assessed all patients at least once a week.

Results: Baseline clinical neurological examination and ENG showed signs of axonal polyneuropathy in 10 of 11 patients before CAR T cell therapy indicating damage due to prior chemotherapy. Two patients presented with slightly impaired MoCA-results (25/30 points) and 1 patient achieved only 23/30 points prior to CAR T cell treatment. Brain MRI was unremarkable in all cases. CSF did not show signs of inflammation in all 8 patients (cell count 1-3/µl, oligoclonal bands negative) and no relevant disturbance of the blood-CSF-barrier (Qalbumin 4.7-8.5). No one exhibited antineuronal or autoimmune encephalitis antibodies. During the four-week follow-up period one patient developed a severe CRS at day 5 accompanied by mild signs of cognitive impairment (MoCA minimum 23/30), but without abnormalities in brain MRI. He died on day 23 following CAR T cell therapy due to infection. Two patients exhibited signs of cognitive impairment at day 4 and 5, respectively. Both patients showed very similar symptoms including apraxia, expressive aphasia, disorientation, and hallucinations. Symptoms developed very quickly, while brain MRI was inconspicuous in either case. Grade 2 ICANS was assumed in both patients and both were treated with dexamethasone 40 mg/d. As symptoms rapidly resolved steroid treatment was quickly tapered and stopped after 5 days. Both patients showed neither signs of cognitive nor neurological impairment afterwards.

Conclusions: Neurotoxicity is a feared complication of CD19 CAR T cell therapy and initial symptoms can be very subtle. Our longitudinal examinations in 11 patients revealed specific clinical symptoms of ICANS in 2 patients without relevant radiological abnormalities. Further studies with higher numbers of patients including a structured and detailed neurological examination are required to uncover CD19 CAR T cell-related neurotoxicity and its especially pathogenesis.

Disclosure: Nothing to declare.

P099 Nutritional Assessment of Patients undergoing CD19-targeted CAR-T Therapy for Non-hodgkin’s Lymphoma and the Short Term Effect of Treatment on Nutritional Status

Katie Ahern, Shafqat Inam, Katie Walker, Orla Stewart, Victoria Potter, Piers Patten, Andrea Kuhnl, Deborah Yallop, Reuben Benjamin, Robin Sanderson

Kings College Hospital NHS Foundation Trust, London, United Kingdom

Background: Chimeric antigen receptor (CAR) T-cell therapy targeting CD19 has demonstrated efficacy in the treatment of relapsed and refractory B cell non-Hodgkin lymphoma. In haematological cancers, nutrition is a concern, particularly in patients undergoing high dose therapies and haemopoietic stem cell transplantation (HSCT). The high-dose radiotherapy/chemotherapy associated with treatment and its typical spectrum of side effects, including nausea, vomiting, mucositis, diarrhoea and infections, further impacts oral food tolerance. This contributes significantly to weight loss (WL), particularly in the first 40 days of admission. As of yet, there have been no reports on the effects of CAR T-cell therapy on nutritional status.

The aim of this study is to report on the nutritional status of patients undergoing CAR T-cell therapy for CD19 positive non Hodgkin lymphoma, both prior to, and during their approximate 3-4 week inpatient admission for treatment.

Methods: 40 patients who underwent treatment between January and October 2019 had a comprehensive nutritional assessment prior to receiving CAR T-cell therapy. Of these patients, 39 had diffuse large B cell lymphoma and one patient mediastinal B cell lymphoma. They were reviewed during their inpatient admission stay and symptoms which impair nutritional intake (e.g. diarrhoea, poor appetite) were monitored, as well as WL and their requirement for oral, enteral and parenteral nutritional interventions.

Results: 25% of patients were identified as malnourished prior to treatment with poor nutritional status typically being related to pre-existing chronic illness e.g. inflammatory bowel disease or disease involving the GI tract. 38 patients were nutritionally assessed as inpatients in the 3-4 weeks after infusion of CAR T-cells. During this period, no significant impact on body weight (5% or more WL) was observed in 66% of patients who underwent therapy. This is hypothesised to be due to the reduced observation of side effects such as vomiting, diarrhoea and mucositis, which are frequently observed with other treatments for haematological cancers, in particular HSCT.. Significant WL during this period (>10% of body weight) was observed in 8% (n=3) of patients.

50% of patient’s required nutritional supplements to meet their requirements and prevent unintentional WL during their admission. 18% (n=7), including all patients who suffered neurotoxicity required a period of enteral feeding via nasogastric tube. In the other 3 cases, nasogastric tube feeding was indicated due to severe anorexia/malnutrition or dysphagia due to disease being localised to the neck region.

Conclusions: CAR T-cell therapy appears to have a less significant impact on nutritional status than other similar treatments for haematological malignancies, primarily due to a lower incidence in adverse effects. However, all patients undergoing treatment should be nutritionally screened prior to treatment due to the high incidence of malnutrition in this population group. Patients who experience neurotoxicity are also at high risk of malnutrition and are likely to require nasogastric enteral feeding for a period to prevent significant WL. Further research on the impact of neurotoxicity on nutritional status, and longer term follow up on the nutritional impact of CAR T-cell therapy is required to influence future dietetic practice in this field.

Disclosure: Nothing to declare.

P100 Effectiveness of Autologous Leukapheresis Collections for CAR T-cell Manufacturing in Patients with B-cell Malignancies

Udo Holtick, Anja Jühling, Philipp Gödel, Hyatt Balke-Want, Nadine Kutsch, Özlem Aylikci, Linda Wilhelm, Hanna Birkholz, Christof Scheid, Peter Borchmann

Universität Köln, Köln, Germany

Background: Chimeric antigen receptor (CAR) T-cell therapy is a novel and promising cellular treatment modality for a variety of malignancies. So far, it is mainly being used in haematological malignancies including relapsed or refractory high-grade lymphoma, acute lymphoblastic leukemia (ALL) and multiple myeloma. An autologous leukapheresis product is collected as source material for the CAR T-cell manufacturing process. This cohort of patients is typically heavily pre-treated, cytopenic and presenting significant disease- or treatment related complications. The effectiveness and feasibility of leukapheresis procedures in this setting was analysed.

Methods: In this retrospective analysis, 66 leukapheresis collections from patients participating in CAR T-cell clinical trials or from patients in preparation for CAR T-cell treatment with tisagenlecleucel in the commercial setting were reviewed. Collections were performed on the COBE Spectra apheresis device by experienced nurses. Pre-apheresis peripheral blood counts, apheresis parameters, and product cell counts were analysed.

Results: Patients with relapsed or refractory diffuse large B-cell lymphoma including Richter’s transformation (n=57), ALL (n=1), mantle cell lymphoma (n=3), follicular lymphoma (n=1) underwent leukapheresis collection for CAR T-cell production. Median age of the patients was 60 years (range 20-83). The median body weight of the patients was 73kg (range 39-137). Median pre-collection CD3 and lymphocyte counts were 540/µl (range 30-3400) and 620/µl (range 90-4960), respectively. The median pre-collection leukocyte count was 5240/µl (range 700-52650) and the median hematocrit was 30% (range 18-44). A median number of 3,92 x10e9 CD3+ T-cells was collected (range 0,2-18,23 x10e9) by processing a median number of 2,1 total blood volumes (range 0,4-3,8). This corresponds to a collection of 0,37x10e9 CD3+ T-cells per liter blood processed. The collection efficiency was 60% (CE2). Only one patient failed to collect sufficient T-cells, in this case in the context of massive tumor progression and infection. Two patients had to be collected twice on consecutive days. Vascular access was a central line in 32 and a peripheral vein in 34 procedures. Leukapheresis was well tolerated in all cases.

Conclusions: Our data demonstrates that a standard leukapheresis is effective to collect sufficient CD3 T-cells for CAR T-cell production. Patients can be safely and successfully collected with CD3 counts down to 50-100 CD3 T-cells/ µl peripheral blood. Follow-up of completed infusion rates and reasons for infusion failure are currently under investigation and will be presented.

Disclosure: The authors have no conflict of interest to disclose.

P101 Definition and Implementation of Clinical and Quality Endpoints in Centers Administering a Commercial CAR-T Product

Ron Ram, Ronit Gold, Odelia Amit, Yael Bar-On, Rinat Eshel, Chava Perry, Nadav Sarid, Yair Herishanu, Noam Benyamini, Irit Avivi

Tel Aviv Medical Center, Tel Aviv University, Tel Aviv, Israel

Background: CAR-T (Chimeric Antigen Receptor Therapy) has become an acceptable therapy option in patients with chemo-refractory DLBCL. Patients in most cases have a rapidly progressive disease hence the CAR-T process should follow a very strict time course to ensure high percentage of patients receiving the final product, while maintaining patents’ safety and product integrity. We aim to develop a clinical and quality management system to ensure the overall success of the procedure.

Methods: We established a system to allow a CAR-T team to self-assess against a group of standard guidelines/procedures. This system will serve as a control process to review, analyse, implement and improve suboptimal results. All subprocesses of the CAR-T were identified and individually dissected into different parameters based on the CARTangle - our unique centre model based on 3 domains - patient, disease and logistics. Subprocesses and domains are prospectively monitored for defined endpoints, flaws, deviations and events, corrective actions and change control procedures are then implemented, when indicated.

Results: The following subprocesses were defined - 1. Referral of a patient and eligibility criteria for the CAR-T program, 2. Bridging to apheresis, 3. Bridging to infusion, 5. infusion of the product and short-term follow-up, and 6. Long-term follow-up. The correspondence clinical and quality management parameters are defined below (Table). Data of enrolled patients with the corresponding quality management parameters will be presented at the meeting.

Conclusions: This pivotal clinical and quality management system is an ongoing process and is obliged to maximize patients and products´ safety and performance.

Disclosure: Nothing to declare.

P102 CAR-T in Breast and other extra-medullary Relapsed/refractory All

Francesco Paolo Tambaro1,2, Sajad Khazal2, Dristhi Ragoonanan2, Priti Tewari2, Demetrios Petropolous2, Jeffrey A Miller2, William G Wierda2, Richard E Champlin2, Kris M Mahadeo2

1AORN Santobono-Pausilipon, Naples, Italy, 2Univeristy of Texas MD Anderson Cancer Center, Houston, TX, United States

Background: Extra-medullary ALL develops in sanctuaries including, CNS, genitourinary and “sequestered sites” (gut, breast, skin). Data regarding complete remission (CR) rates and durability of response among patients receiving CART with relapsed/refractory (r/r) ALL and extra-medullary disease is still emerging.

Methods: We report two AYA patients with r/r ALL and extra-medullary involvement who achieved CR after tisagenlecleucel.

Results: Patient 1 was refractory to 7 prior lines of therapy and developed CNS, liver, spleen and bilateral kidney involvement; He experienced CD19 negative relapse approximately 8 weeks later. He subsequently achieved CR following two doses of inotuzumab and then received a reduced intensity (RIC) related haplo-identical SCT. He experienced a CNS relapse approximately 2 months later and died shortly after. Patient 2 had isolated bilateral breast involvement following allogeneic stem cell transplantation (SCT). She experienced swelling and erythema of the breast tissue following CART and achieved MRD negative CR in the bone marrow with partial response in the breast. She subsequently received XRT to the breast and was consolidated with a RIC SCT. She died approximately 100 days post-SCT from sepsis.

Conclusions: The majority of 53 reported patients with ALL and extra-medullary breast involvement (22 occurred post-SCT) received combined radiation and chemotherapy; 4 received DLI and achieved CR but 2 died of severe GvHD. CAR-T cells, may likewise circulate and act in sequestered sites but without GvHD. Lympho-depletion preceding CAR-T may also eliminate regulatory T lymphocytes and potentially enhance the immune response. Combined treatment with CAR-T and radiation may help eradicate extra-medullary disease, taking advantage of the local death of dividing cells with radiation with potential enhancement of the microenvironment to facilitate CAR-T function and enhance anti-tumor immune response of resident T cells. Future studies will elucidate the optimal timing of CART among patients with extra-medullary disease, which may improve durability of response and long-term outcomes.

Disclosure: Nothing to declare.

P103 Predicting CAR T-cell Infusion after Successful Manufacturing: real-world Data

Georg-Nikolaus Franke, Eberhard Schleyer, Konstantin Weibl, Hansjakob Fries, Sophia Michel, Rosmarie Pointner, Dominic Brauer, Sandra Otto, Uwe Platzbecker, Vladan Vucinic

University of Leipzig Medical Center, Leipzig, Germany

Background: CAR T-cells directed against CD19 are a newly approved cellular therapy for treating patients (pts) with relapsed or refractory (r/r) pediatric and adolescent acute lymphoblastic leukemia or diffuse large B-cell lymphomas (DLBCL). Given the aggressive nature of the underlying diseases bridging pts from lymphapheresis (LA) to CAR T-cell infusion remains a challenging task. Very little is known on factors predicting successful bridging pts during this period in the real world population.

Methods: We evaluated clinical variables potentially affecting successful re-infusion of CAR T-cells in pts receiving CD19 CAR tisagenlecleucel at our CAR T-cell center.

Results: Ten pts were assigned to CAR T-cell therapy and underwent LA between May to August 2019 for r/r DLBCL. 3 pts died prior to infusion. 7 pts received CAR T-cells after a median time of 49 days after LA. Pts receiving the CAR T-cells presented with lower lactate dehydrogenase (LDH) and C-reactive protein (CrP), better ECOG performance score (PS) at the time of LA and had received fewer lines of therapy than patients not receiving CAR T-cells. We developed a scoring system, which included the mean LDH (>8.3 µkat/l) and CrP (>90 mg/l) at the time of LA forpatients that did not receive the CAR T-cells (2 points each), ECOG PS (1 point per ECOG PS), lines of therapy after 1st salvage (1 point per line) and referral from an external hospital (1 point) in order to predict outcome. All but one patient receiving the CAR T-cells had a score of < 5.

Conclusions: Bridging eligible patients from LA to CD19 CAR T-cell infusion remains a challenge. Patients with a CAR T score >4 should be considered to be at higher risk for complications. The proposed score has to be evaluated in a larger cohort.

Disclosure: Franke: Novartis, Pfizer, Jazz, MSD, Takeda: Honorary. Gilead: travel support

Vucinic: Novartis, Gilead, Takeda, Abbvie: Honorary

P104 Evaluation of the Interest of a Drug Reconciliation Activity in Patients Treated with Car T-cells: A Descriptive Study

Flore Durieux1, Nicolas Simon1,2, Héloïse Henry1,2, Benjamin Podvin1, Marc Ducatel1, Amandine Legrain1, Valentin Douilly1, David Beauvais1, Bertrand Décaudin1,2, Ibrahim Yakoub-Agha1,3, Pascal Odou1,2

1CHU Lille, Lille, France, 2University of Lille, Lille, France, 3LIRIC, INSERM U995, Université de Lille, Lille, France

Background: CAR T-cells (CARTc) are patient T-cells that express artificial chimeric antigenic receptors (CAR) capable of recognizing tumor cells antigen. Axicabtagene ciloleucel is indicated in patients with relapsed diffuse large B-cell lymphoma or those who are refractory to other treatments. A medication reconciliation activity has been carried out since the beginning of 2019. The objective is to assess the value of medication reconciliation at admission of patients receiving CARTc.

Methods: A medication reconciliation have been conducted by pharmacy students under the supervision of pharmacists for patients receiving CARTc. A medication history, including self-medication treatments, has been established according to at least 3 information sources. Intentional or unintentional discrepancies were underlined for each difference between the medication history and the first medical prescription at admission. Pharmaceutical interventions (PI) resulted from a discrepancy. Medication adherence was assessed according to the medication adherence scale of our national insurance system. Patients were considered: good, minimal or not adherent. In parallel, allergies and medication difficulties were reported. Data were prospectively recorded anonymously on an Excel® datasheet.

Results: Between January 3rd and October 30th, 2019, 30 patients received CARTc. The age was 60±10 years and gender ratio was 0.7. Patients received 4±2 previous lines of treatment. Reconciliation could have been performed in 18 patients. They took an average of 6 medications ([1; 19]), notably anti-infectious prophylaxis: valaciclovir (N=12/18) and co-trimoxazole (N=9/18). Intentional discrepancies (N=93) and unintentional discrepancies (N=8) were found. Six PI were formulated, and 5 accepted: 1 discontinuation of lansoprazole (no indication found), 1 dose adjustment for irbesartan, 1 dosage error for morphine, 2 missed treatment continuations (pravastatin and isradipine). Patients were considered good adherent (N=4/18), minimal adherent (N=12/18) and not adherent (N=2/18). The main reasons for low adherence were notably: too many tablets to take, forgetfulness, and delays. No patients had any trouble for drug intake. Acetaminophen was the main self-medicating drug.

Conclusions: During the study period, some patients were not reconciled due to a lack of staff in the department, particularly at the beginning of the year. Usually, the studied population takes few drugs. Therefore, some patients took more than 10 drugs. In this study, drug adherence was often minimal as shown in a literature review that evaluates drug adherence in patients receiving hematopoietic stem cell transplantation1. This shows that reconciliation activity for these patients appears essential in order to review treatments, insist on medication adherence and to prevent the risks of drug-drug interaction, especially with the conditioning regimen. The data from this preliminary study need to be confirmed on a larger population.

1 Morrison CF, Martsolf DM, Wehrkamp N, Tehan R, Pai ALH. Medication Adherence in Hematopoietic Stem Cell Transplantation: A Review of the Literature. Biology of Blood and Marrow Transplantation. avr 2017;23(4):562-8.

Clinical Trial Registry: /

Disclosure: /

CAR-based Cellular Therapy – preclinical

P105 Breaking PD-l1-mediated Resistance in anti-CD19 and anti-CD22 Car T Cells with PD-1/CD28 Fusion Receptors

Franziska Blaeschke1, Antonia Apfelbeck1, Dana Stenger1,2, Jasmin Mahdawi1, Mareike Lepenies1, Felicitas Rataj3, Semjon Willier1, Theresa Kaeuferle1, Thomas G. P. Gruenewald2,4, Robbie G. Majzner5, Dirk H. Busch6,8, Sebastian Kobold3, Tobias Feuchtinger1,2,7

1Dr. von Hauner Children’s Hospital, Medical Center of the University of Munich, Munich, Germany, 2National Center for Translational Oncology Research (DKTK), Munich, Germany, 3Medical Center of the University of Munich, Ludwig-Maximilians University Munich, Member of the German Center for Lung Research, Munich, Germany, 4Max-Eder Research Group for Pediatric Sarcoma Biology, Ludwig-Maximilians University Munich, Munich, Germany, 5Stanford University, Stanford, CA, United States, 6Technical University Munich, Munich, Germany, 7National Center for Infection Research (DZIF), Munich, Germany

Background: Therapy with autologous T cells expressing an anti-CD19 chimeric antigen receptor (CAR) has been recently approved for patients with B-cell lymphoma and B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Despite tremendous success in pediatric BCP-ALL, 40 to 50% of the patients do not experience long-term relapse-free survival after CAR T-cell treatment. Allogeneic stem cell transplantation (allo-SCT) is offered to selected patients after CAR treatment to prevent relapse.

Methods: To increase functionality of conventional anti-CD19 and anti-CD22 CAR T cells pre allo-SCT and protect the T cell from leukemia-mediated inhibition, a PD-1/CD28 fusion receptor was designed. Fusion receptors convert an inhibitory signal into an intracellular activation cascade. PD-1/CD28 anti-CD19 and anti-CD22 CAR T cells were functionally characterized and compared to conventional CAR T cells in terms of cytotoxic capacity, proliferation, activation and cytokine release after single and multiple contact with leukemic cells.

Results: The impact of prominent co-inhibitory immune checkpoint axes (such as PD-1/PD-L1) for relapse or non-response to CAR T-cell therapy is not yet fully understood. Bone marrow analyses of >100 BCP-ALL patient samples pre allo-SCT showed substantial heterogeneity in initial PD-L1 expression levels of leukemic blasts and the ability to up-regulate PD-L1 upon T-cell attack. Cytokine release of conventional 2nd generation anti-CD19 CAR T cells was significantly reduced after contact with a PD-L1 overexpressing ALL. We hypothesized that a PD-1/CD28 fusion receptor can increase functionality of conventional CAR T cells while protecting the T cell from leukemia-mediated inhibition. Anti-CD19 CAR T cells with PD-1/CD28 fusion receptors were generated and showed strong CD19-dependent cytotoxicity, proliferation, activation and cytokine release. No unspecific cytokine release mediated by the fusion receptor in absence of CD19 was detected. In presence of PD-L1, fusion receptor CAR T cells out-competed conventional 1st and 2nd generation anti-CD19 CAR T cells and released significantly higher levels of Th1 cytokines IFN-γ, IL-2 and TNF-α. PD-1/CD28 anti-CD19 CAR T cells were able to persist after >4-fold stimulation with leukemic cells and showed significantly increased long-term killing capacity and cytokine release compared to conventional CAR T cells after multiple stimulations. Superiority of CAR T cells with PD-1/CD28 fusion receptor was confirmed in an anti-CD22 CAR T cell model.

Conclusions: Anti-CD19 and anti-CD22 CAR T cells with PD-1/CD28 fusion receptor can increase functionality of conventional CAR T cells by circumventing leukemia-induced T-cell inhibition pre allo-SCT.

Disclosure: Nothing to declare.

P106 Allogeneic Chimeric Antigen receptor-invariant Natural Killer T Cells Exert Both Direct and Indirect Antitumor Effects through Host Cd8 T Cell cross-priming

Federico Simonetta1,2, Toshihito Hirai1, Juliane K. Lohmeyer1, Kristina Maas-Bauer1, Maite Alvarez1, Arielle S. Wenokur1, Jeanette Baker1, Amin Aalipour1, Samuel Haile3, Crystal L. Mackall3, Robert S. Negrin1

1Stanford University, Stanford, CA, United States, 2Geneva University Hospitals, Geneva University, Geneva, Switzerland, 3Stanford Cancer Institute, Stanford, CA, United States

Background: Chimeric antigen receptor (CAR) T cells have shown impressive results in B-cell malignancies but, unfortunately, their widespread use is still limited by the logistical and financial burdens related to the need of generating autologous cell products. The development of universal allogeneic CAR T cells to be used off-the-shelf has faced major limitations, namely the risk of Graft-versus-Host-Disease (GvHD) induction and the rejection of the cells by the host immune system. Invariant Natural Killer-T (iNKT) cells are innate lymphocytes deprived of GvHD induction potential and displaying antitumor effects, both directly and indirectly, through enhancement of CD8 T cell responses. Preclinical studies in xenogeneic mouse models demonstrated the feasibility of using iNKT cells as a platform for CAR-based therapies, and two clinical trials are currently ongoing. In this work, we assessed the immunoadjuvant effect of allogeneic CD19-specific iNKT CAR on the host immune system.

Methods: We transduced murine iNKT cells from FVB/N (H-2Kq) mice with a CD19-specific CD28/CD3ζ CAR and assessed their antitumor effect in vitro and in vivo.

Results: CD19-iNKT CAR had a direct cytotoxic effect in vitro against the CD19+ A20 lymphoma cells and significantly improved survival of mice after administration to major histocompatibility complex (MHC)-mismatched, immunodeficient BALB/c (H-2Kd) Rag2-/- gamma-chain-/- mice receiving A20 lymphoma cells (2x10e4; Figure 1A) without inducing any signs of GvHD. To test the efficacy of iNKT CAR cells in the presence of host immune cells, we employed BALB/c mice receiving sublethal irradiation (4.4 Gy), resulting in only a partial and transient lymphopenia. The antitumor effect of allogeneic iNKT CAR cells was greatly enhanced suggesting the participation of host cells in the antitumor effect. Interestingly, the iNKT CAR effect was partially abrogated when we employed as recipients BALB/c BATF3-/- mice, in which CD8 T cell cross-priming is impaired as a result of the absence of BATF3-dependent CD103+ CD8a+ dendritic cells known to play a role in iNKT cell interactions with other immune effector cells. Moreover, co-administration of allogeneic FVB/N iNKT CAR with autologous BALB/c CD8 T cells at the time of transfer of T-cell-depleted autologous bone marrow cells and A20 cells into lethally irradiated BALB/c recipients resulted in a synergistic effect. To prove the induction of tumor specific CD8 T cell responses, host CD8 T cells were isolated at day 60 from sublethally irradiated BALB/c mice receiveing A20 cells and treated with iNKT CAR. CD8 T cells primed in the presence of iNKT CAR transferred into new lethally irradiated recipients receiving A20 cells and BM from syngeneic Rag2-/- gamma-chain-/- mice significantly increased survival. Due to their immuno-adjuvant effect on host CD8 T cells, low numbers of allogeneic iNKT CAR outperformed allogeneic conventional CAR T (Tcon CAR) when administered to sublethally irradiated BALB/c mice receiving A20 cells.

Conclusions: Collectively, these results demonstrate the potent immunoadjuvant effect exerted by allogeneic iNKT CAR cells toward the host immune system suggesting that iNKT CAR cells are an attractive off the shelf product for adoptive immunotherapy.

Clinical Trial Registry: N/A

Disclosure: Nothing to disclose

P107 NKG2D Chimeric Antigen receptor-expressing Lymphocytes Target Acute Myeloid Leukemia Cells

Alejandra Leivas1, Laura Córdoba1, Antonio Valeri1, Mari Liz Paciello2, Paula Rio3, Daniel Primo4, Joan Ballesteros4, Lucía Fernández5, Antonio Pérez-Martínez6, Dean A. Lee7, Daniel J. Powell Jr.8, Joaquin Martinez-Lopez1

1Hospital Universitario 12 de Octubre, Spanish National Cancer Center, Madrid, Spain, 2Hospital Universitario 12 de Octubre, Madrid, Spain, 3Research Center for Energy, Environment and Technology, Madrid, Spain, 4Vivia Biotech, Madrid, Spain, 5Spanish National Cancer Center, Madrid, Spain, 6Hospital Universitario La Paz, Madrid, Spain, 7The Research Institute At Nationwide Children’s Hospital, Columbus, OH, United States, 8University of Pennsylvania, Philadelphia, PA, United States

Background: Chimeric antigen receptor (CAR) therapy is showing promising results in hematological malignancies. Since AML exhibits high heterogeneity and does not have specific differential antigens of the hematopoietic stem cell, using NKG2D-CAR cells could be an appropriate therapeutic strategy against AML. NKG2D receptor has a wide range of specific tumor cell ligands expressed in more than 80% of all tumors. Here we evaluate the anti-tumor activity of activated and expanded natural killer cells (NKAE) and T cells expressing an NKG2D CAR.

Methods: T cells and NK cells were isolated from the healthy donor´s PBMCs (n=5). NKAE cells were obtained by co-culture with subletally irradiated CSTX002 cells. Then, NKAEs and T cells were transduced with an NKG2D CAR. The efficiency of transduction was evaluated by flow cytometry. The cytotoxicity and toxicity on healthy tissues was evaluated by 4 hour europium release assay. The safety of NKG2D-CAR transduced cells was evaluated using CGH arrays.

Results: Both the AML cell lines and primary blasts from AML patients showed expression of the MICA/B and ULBPs-1 to 3 ligands (high expression of at least 3 of the 5 analyzed ligands). Four hour europium release assays revealed that untransduced T cells had higher cytotoxicity than untransduced NKAE cells at the same ratio (32:1) against both OCI-AML-3 cytarabine-resistant cell line (52.7% ± 14.2% vs. 32.5% ± 7.2%) as to the cytarabine-sensitive cell line (56.42% ± 5.6% vs. 50.14 % ± 5.9%). T cells showed a better transduction efficiency than NKAE cells at a multiplicity of infection (MOI) of 5. It was observed that both the CAR-NKAE cells and the CAR-T cells had higher cytotoxicity against these two lines (OCI-AML-3R and OCI-AML-3S) after being transduced with our NKG2D-CAR. However, the antitumor activity of CAR-T cells always remained superior to that of the CAR-NKAE for both OCI-AML-3R (54.26% ± 3.8% vs. 35.3% ± 6.7%) and for OCI-AML-3S (63.36% ± 3.5% vs. 54.3% ± 3.7%) cell lines, with a greater difference compared to drug resistant cells. The antitumor activity of CAR-T cells and CAR-NKAE cells was always superior on the sensitive cell line. The antitumor activity of NKG2D CAR-T cells was evaluated against primary blasts from AML patients (n = 4), observing a nearly complete destruction of the blasts after 24 hours, at low target: effector ratio (4:1). CAR-T cells were highly positive to CD45RO and showed reduced expression of CD45RA. They showed high IL-2 production exhibiting a central memory phenotype. CAR-T cells exhibited some toxicity on third party PBMCs being null in the case of CAR-NKAE. CGH arrays studies showed no variation in the copy number, resulting from the introduction of the CAR. In vivo studies are ongoing.

Conclusions: AML cells could be target with an NKG2D-CAR. Primary NKAE cells and T cells can be transduced with an NKG2D-CAR at a very low MOI to enhance their antileukemic activity. CAR-T cells were able to completely destroy AML blasts. Although further studies are needed, these results show the potential of NKG2D-CAR T and NK cell therapy in AML.

Disclosure: Dean A. Lee declare.s an equity interest, advisory role, and intellectual property licensing to CytoSen Therapeutics and Kiadis Pharma, and advisory role with Caribou BioSciences and Courier Biosciences. Daniel J. Powell Jr. hold patents in the area of CAR T cell therapy. Rest of the authors have nothing to declare.

P108 Clinical-grade Manufacturing of ROR1 CAR T-cells using a Novel virus-free Protocol

Katrin Mestermann1, Marie Eichler2, Markus Machwirth1, Kati Kebbel2, Ulrike Köhl2, Hermann Einsele1, Claudia Müller2, Jörg Lehmann2, Tamás Raskó3, Felix Lundberg3, Zsuzsanna Izsvák3, Gerno Schmiedeknecht2, Michael Hudecek1

1Universitätsklinikum Würzburg, Würzburg, Germany, 2Fraunhofer-Institut für Zelltherapie und Immunologie, Leipzig, Germany, 3Max-Delbrück-Centrum für Molekulare Medizin, Helmholtz Gemeinschaft, Berlin, Germany

Background: Immunotherapy with T-cells that were modified to express a ROR1-specific chimeric antigen receptor (ROR1 CAR-T) has therapeutic potential in ROR1+ malignancies in hematology and oncology. In toxicology studies in non-human primates, the adoptive transfer of ROR1 CAR-T did not disclose relevant clinical toxicity, encouraging the initiation of clinical trials to assess the safety and efficacy of ROR1 CAR-T therapy in patients with advanced ROR1+ malignancies. In this study, we sought to establish and validate clinical-grade manufacturing of ROR1 CAR-T to enable a Phase I/IIa clinical trial. In particular, we sought to integrate virus-free gene-transfer based on Sleeping Beauty transposition into this manufacturing protocol to easily permit scale-up, and to reduce the regulatory burden associated with conventional viral gene-transfer.

Methods: Buffy coats or leukaphereses were obtained from healthy donors to perform protocol optimization (n=7) and scale-up runs (n=1). CD4+ and CD8+ T cells were isolated separately and stimulated with CD3/CD28 TransACT reagent (Miltenyi). T cells were transfected with mRNA encoding hyperactive Sleeping Beauty transposase (SB100X) and minicircle DNA encoding a pT2 transposon comprising the ROR1 CAR and an EGFRt marker gene using the MaxCyte GTx electroporation platform. Following transfection, T cells were expanded for 10-13 days in G-REX bioreactors and then harvested and formulated into the drug product at a 1:1 ratio of CAR-expressing CD4:CD8 T-cells. The drug product underwent comprehensive phenotypic, functional and genomic analyses as part of product qualification.

Results: The set of protocol optimization runs provided insights into the optimal timing between T-cell activation and transfection, as well as the amount of SB100X mRNA and ROR1 CAR minicircle DNA for transfection into the T-cells. On average, the stable gene-transfer rate at the end of the manufacturing process was 71% in CD4+ (n=5) and 54% in CD8+ T-cells (n=7). The average yield of CAR-expressing T-cells relative to the number of input T-cells was 12.6-fold for CD4+ and 9.4-fold for CD8+ after 12-15 days of expansion, with an average viability of 84% for CD4+ and 82% of CD8+ T-cells. The set of scale-up runs was performed with leukapheresis product from which 70x10^6 CD4+ T-cells and 130x10^6 CD8+ T-cells were further processed. At the end of the manufacturing process on day 12, there were 844x10^6 CAR-expressing CD4+ and 857x10^6 CAR-expressing CD8+ T-cells, which equals a 16-fold and 7.9 fold expansion relative to the input T-cell number, respectively. Overall, ROR1 CAR-T showed specific recognition and potent elimination of ROR1+ target cells, as well as antigen-dependent cytokine production and productive proliferation. Experiments to determine the anti-tumor potency of the drug product in vivo and detailed genomic analyses are ongoing.

Conclusions: With this novel protocol, we aim to obtain the first manufacturing license for CAR-T in Europe that integrates our optimized approach with SB100X mRNA and transposon minicircle DNA for CAR gene-transfer on the MaxCyte transfection platform. The quality and yield of the drug product support the design and dose escalation of the proposed clinical trial with ROR1 CAR-T, and will serve as a blueprint for other CAR-T products from our pipeline.

Disclosure: Nothing to declare.

P109 Lentivirally and Alpharetrovirally Engineered CD19-specific Chimeric Antigen Receptor Natural Killer Cells are Highly Cytotoxic against Acute Lymphoblastic Leukemia

Tobias Bexte1,2,3, Stephan Müller1,2,3, Veronika Gebel1,2, Franziska Kalensee1,2, Eva Stolzenberg1, Jessica Hartmann4, Ulrike Koehl5,6,7, Axel Schambach8,9, Wels Winfried S.3,10,11, Ute Modlich12, Evelyn Ullrich1,2,3

1University Hospital Frankfurt, Goethe University, Frankfurt, Germany, 2University Hospital Frankfurt, Goethe University, Frankfurt, Germany, 3German Cancer Consortium (DKTK) partner site Frankfurt/Mainz, Frankfurt, Germany, 4Paul-Ehrlich-Institut, Langen, Germany, 5Fraunhofer Institute for Cell Therapy and Immunology (IZI), Leipzig, Germany, 6Hannover Medical School, Hannover, Germany, 7University Leipzig, Leipzig, Germany, 8Hannover Medical School, Hannover, Germany, 9Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States, 10Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, Frankfurt, Germany, 11Frankfurt Cancer Institute, Goethe University, Frankfurt, Germany, 12Paul-Ehrlich Institut, Langen, Germany

Background: Autologous chimeric antigen receptor-modified (CAR) T cells with specificity for CD19 showed potent antitumor efficacy in clinical trials regarding relapsed and refractory acute lymphoblastic leukemia (ALL). Natural killer (NK) cells are cytotoxic lymphocytes that are capable to kill their targets in a non-specific manner and additionally do not cause GvHD. Therefore, using CD19-CAR-NK cells exhibits several advantages, such as safety in clinical use, possible allogenic settings and the potential to also attack heterologous leukemia cells which lost CD19. Here, we focused on the optimization of generating CD19-CAR-NK cells by viral transduction under feeder-cell free conditions.

Methods: Human NK cells were isolated from healthy donor peripheral blood mononuclear cells via CD56 negative selection. After a feeder-cell free expansion phase with interleukin 15 (IL-15), transductions were performed with a CD19-CAR encoding vector at different multiplicities of infection (MOI). To optimize gene modification different viral vector systems were compared using lentivirus and alpharetrovirus, pseudotyped with either VSV-G or RD114-TR. Finally, generated CD19-CAR-NK cells were tested in their ability to kill CD19-positive and CD19-negative cell lines.

Results: Transduction efficiencies of NK cells transduced with the RD114-TR pseudotyped alpharetroviral or lentiviral CD19-CAR vectors outperformed transduction with VSV-G pseudotyped lentiviral vector (lentiviral/RD114-TR: MOI 1: 10,9%, MOI 5: 24.0%, MOI 10: 27.3%; alpharetroviral/RD114-TR: MOI 1: 14.7%, MOI 5: 28.5%, MOI 10: 37.4%; lentiviral/VSV-G: MOI 1: 0.9%, MOI 5: 4.4%, MOI 10: 8.2%). As possible mechanism, dependent on IL-15, we observed a significant upregulation of the surface expression of ASCT-2 on the primary NK cells that is an entry receptor for RD114-pseudotyped vectors.

Remarkably, CD19-CAR-NK cells generated by RD114-TR pseudotyped retroviral vectors showed stable transgene expression and were able to expand almost as good as non-transduced (NT) NK cells over a time period of 14 days.

Independent of the transduction method, engineered CD19-CAR-NK cells showed an impressively high cytotoxic capacity against CD19-positive ALL cells compared to NT-NK cells; alpharetroviral/RD114-TR CD19-CAR-NK inducing 73.1% vs. lentiviral/RD114-TR CD19-CAR-NK cells inducing 74.7% vs NT- NK cells inducing 35.9% of cell death; E:T ratio 1:1 in 4 hours).

Conclusions: CD19-CAR-NK cells can be successfully generated under feeder-cell free conditions using different transduction enhancers and viral vector systems. Our data suggest the usage of Vectofusin-1 in combination with RD114-TR pseudotyped retroviral vectors to genetically modify NK cells to achieve sufficient amounts of highly cytotoxic transduced cells. These CD19-CAR-NK cells mediate high cytotoxicity and therefore may offer a new therapeutic option in the treatment of ALL. These insights will be transferable in CAR-NK-cell engineering to target different other malignancies.

Disclosure: Axel Schambach is an inventor on a patent describing alpharetroviral SIN vectors. Winfried S. Wels is an inventor on a patent describing chimeric antigen receptors with an optimized hinge region. The remaining authors have nothing to disclose.

P110 Novel Strategies to Enhance the safety of CAR T-cell Immunotherapy: The Imsavar Project

Miriam Alb1, Jonathan Moggs2, Lars Wallstabe1, Benedikte Hatz1, Hermann Einsele1, Peter Loskill3, Andries van der Meer4, Scott Wagers5, Ulrike Köhl6, Michael Hudecek1

1imSAVAR Consortium, Würzburg, Germany, 2imSAVAR Consortium, Basel, Switzerland, 3imSAVAR Consortium, Stuttgart, Germany, 4imSAVAR Consortium, Enschede, Netherlands, 5imSAVAR Consortium, Maasmechelen, Belgium, 6imSAVAR Consortium, Leipzig, Germany

Background: Adoptive immunotherapy with gene-engineered CAR-T-cells is a transformative treatment in hematology but can be associated with significant toxicity from e.g. cytokine release syndrome (CRS). Preclinical testing to assess CRS is not standardized and there is a strong medical need and desire to establish algorithms to assess the propensity of novel CAR-T-cell products and technologies to induce CRS and other toxicity. imSAVAR - immune safety avatar - is an EU Innovative Medicines Initiative (IMI) project that tackles this challenge in a joint academia-industry consortium and seeks to establish a framework and platform for assessing the utility of innovative non-clinical models and endpoints for enhancing the safety assessment of e.g. CAR-T cells.

Methods: imSAVAR is pursuing a 4-step approach: Step 1 comprises a systematic literature review on pathophysiology and clinical occurrence of CRS after CAR-T-cell therapy. Step 2 comprises a survey amongst academia and industry stakeholders to identify current gaps of existing and emerging preclinical test systems that are used to assess CRS. Step 3 is an open multi-stakeholder workshop that also engages EU and US regulators and patients to determine a roadmap for studies that establish a new set of non-clinical assays and endpoints that will subsequently be validated for their ability to enhance hazard identification, provide mechanistic insight, and help mitigate clinical safety concerns in Step 4.

Results: In Step 1 imSAVAR established a new conceptual map of CRS pathogenesis as an immune-related adverse outcome pathway (irAOP) comprising key molecular events (CAR target antigen engagement, signaling and T-cell activation) and cellular events (CAR-T-cell migration to tumor site, engagement with tumor cells in an immune synapse, secretion of pro-inflammatory mediators, activation of tissue resident and endothelial cells, and systemic inflammation). To each of these events, existing and emerging pre-clinical assays were allocated. In Step 2, a pilot survey was conducted with n=3 CAR-T-cell products from within the consortium. Encouragingly, the repertoire of novel test systems available in imSAVAR for evaluating CAR-T mediated cytokine release include in vitro co-culture assays of CAR-T with tumor cells, single-cell resolution molecular endpoints, in vivo humanized mouse models (e.g. NSG-3G) as well as microphysiologic organ-on-a-chip models. imSAVAR is preparing an open survey to collect data from n≥10 CAR-T and n≥10 other immune-oncology products to inform the research roadmap. All data will then be normalized and correlated with clinical data to identify optimal pre-clinical assays for enhancing the assessment and prediction of CRS.

Conclusions: imSAVAR has established an irAOP that will enable the development and validation of novel non-clinical assays that aim to enhance the characterization of CAR-T-cell associated cytokine release during pre-clinical development. This effort is ultimately anticipated to enhance the safety assessment of therapeutic CAR-T products, thus potentially accelerating patient access to CAR-T products with an enhanced therapeutic index. This CAR-T irAOP strategy forms part of imSAVAR’s broader efforts to enhanced non-clinical safety assessment algorithms for additional immunomodulatory therapeutic modes-of-action (e.g. TCR-transgeneic T cells, bi-specific T-cell engaging antibodies; checkpoint inhibitor antibody combinations; Treg modulators), and a range of immune system-related toxicities (e.g. ICANS, infections).

Disclosure: Nothing to declare. This project receives funding from the Innovative Medicines Initiative 2 Joint Undertaking under grant agreement No 853988.

P111 Adult Peripheral Blood and Umbilical Cord Blood NK Cells Are Good Sources for Effective Car Therapy Against CD19 Positive Leukemic Cells

Lara Herrera1,2, Silvia Santos1,2, Miguel Ángel Vesga1,2, Juan Anguita3,4, Itziar Martin-Ruiz3, Tomás Carrascosa2,5, Manel Juan6, Cristina Eguizabal1,2

1Basque Center for Blood Transfusion and Human Tissues, Galdakao, Spain, 2Biocruces Bizkaia Health Research Institute, Barakaldo, Spain, 3CIC bioGUNE, Derio, Spain, 4Ikerbasque, Basque Foundation for Science, Bilbao, Spain, 5Hospital Galdakao-Usansolo, Galdakao, Spain, 6Hospital Clínic de Barcelona, Hospital Sant Joan de Déu, Institut d’Investigacions Biomèdiques August Pi i Sunyer Hospital, Universitat de Barcelona, Barcelona, Spain

Background: Among hematological cancers, Acute Lymphoblastic Leukemia (ALL) and Chronic Lymphocytic Leukemia (CLL) are the most common leukemia in children and elderly people respectively. Chimeric antigen receptor (CAR) therapy is one of the newest and more effective treatments against these cancers. CAR T cell therapy presents still some risks for the patients, including cytokine release syndrome (CRS) and neurotoxicity. We proposed NK cells from different cell sources for allogeneic CAR therapy.

Methods: 1. Enrichment and culture of NK cells from AB and CB. NK cells were isolated from AB or CB PBMCs by negative selection after magnetic cell isolation. Then, the NK cells were cultured with IL-2 and IL-15 for 8 days.

2. CD19-CAR lentiviral transduction to AB and CB NK cells

3. Functional assays facing CD19-CAR transduced and non-transduced AB and CB NK cells against CD19 expressing target cells. We measure CD107a marker in degranulation assays; and Calcein-AM released by target cells in cytotoxicity assays.

Results: 1. Percentage of the purity of the CD56+ NK cell population was 92.68±2.90 in AB and 91.46±5.14 in CB. NKp46 levels during the culture increase significantly from day 0 to day 7 in both cell sources. In fact, CB NK cells were significantly more stimulated than AB NK cells. We obtained more cells from the isolation from CB than from AB. During the first week, both sources expanded similarly; however, slightly higher fold expansion was observed after two weeks in CB NK cells

2. The mean AB CAR-NK transduction efficiency was 47.46 (range 62.6-20.2%; n=12) while CB CAR-NK transduction efficiency was 46.8 (range 79.7-18.1%; n=12). Seven days post-transduction the viability of AB and CB NK cells remained at 78.85% ± 10.18% and 76.2% ± 5.3%, respectively. In both cases, viability decreased over time until day 28. CAR expression shows a stable decrease of transduction from 40% to 20% with time as determined by flow cytometry every 7 days.

3. On one hand, when exposed to CD19 positive cells, AB CD19-CAR NK cells showed a significantly higher degranulation than non-transduced AB NK cells. On the other hand, when exposed to CD19 positive cells, CB CD19-CAR NK cells showed a significantly higher degranulation than non-transduced CB NK cells. We observed the same results when performing a cytotoxicity assay. AB CD19-CAR NK cells kill slightly better than CB CD19-CAR NK cells.

Conclusions: - CB NK cells present a more stable number of cells per unit than AB NK cells, and they can be stimulated with different interleukins in order to enhance the in vitro expansion, their killing activity and survival.

- Despite the difficulty of infecting NK cells, in our hands we obtain around 40-50% of infection with AB and CB NK cells with CD19-CAR.

- CD19 expressing target cells are killed more efficiently by AB and CB NK cells transduced with CD19-CAR than by non-transduced AB and CB NK cells.

CD19-CAR infected NK cells from AB and CB kill similarly CD19 expressing target cells. However, we observe a higher degranulation of the AB NK cells.

Disclosure: Nothing to declare.

P112 Tyrosine Kinase Inhibitor Followed by Cart Therapy for the Treatment of Relapsed Philadelphia chromosome-positive B-cell Acute Lymphoblastic Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

YUEHUI LIN, Biping Deng, Zhichao Yin, Lihong An, Defeng Zhao, DAN LIU

Beijing Boren Hospital, Beijing, China

Background:

Philadephia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) is a distinct type of ALL, which has a high incidence of adult patients and a dismal poor prognosis. Resistance/relapse(r/r) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remain a significant challenge. Once relapsed, almost patients are resistant to the TKI because T315I mutation of ABL-kinase domain mution(AKDM).

Chimeric antigen receptor T-cells (CART) has shown a higher complete remission(CR)rate in r/r B-ALL patients and has a good security.

So we sequentially applied CART and TKI therapy to treat the Ph+ALL patients relapsed after allo-HSCT and observed the effect.

Methods: From January 1,2018 to June 31,2019, fourteen adult Ph+ALL patients relapsed after allo-HSCT were enrolled. CD19 and/or CD22 expression on blasts and AKDM were detected by flow cytometry(FCM) and polymerase chain reaction(PCR), respectively.

Recipient-derived donor T cells were collected and cultured CART cells, which were transfected by lentiviral vectors encoding the CAR composed of CD3zeta-4-1BB.

ALL patients received fludarabine with or without cyclophosphamide before CART cell infusion, some patients received othder chemotherapy or TKI based on the precondition because high disease burden or extramedullary disease (EMD). CART cell dose was 0.5-2×105/kg (CD19-CART) and 1-2.8×105/kg (CD22-CART). After CART cell

infusion, CART cell, cytokines were measured on D7, D9, D11 etc. and other days depending on the patient’s condition. We evaluated Bone marrow(BM) and cerebrospinal fluid (CSF)morphology, minimal residual disease(MRD)by FCM and BM BCR-ABL1fusion transcripts by real-time quantitative PCR(QPCR) on D30, EMD was examined by imaging examination and once every month later.

Once these patients acquired CR, TKI treatment was followed according to the AKDM and followed up to November 26,2019(6-22 months).

Results: Fourteen patients were aged 17 to 55 years(medium 29), including ten P190, three P210, one special BCR-ABL1 and nine hematological relapse, two FCM-MRD+, two BCR-ABL1+:one with multiple EMD, one only central nervous system leukemia(CNSL). After HSCT, twelve patients relapsed within 12 months(1.5-12 months), two patients relapsed in the 28th and 48th month. Twelve patients had received chemotherapy, TKI, donor lymphocyte infusion (DLI), murinized CD19-CART, radiotherapy before, but all failed;Two patients didn’t received any therapy.

Thirteen patients were detected AKDM:five T315I, one T315I and Y253H, one T315L, one Y317L, five no mutation(one T315I before HSCT). One patient didn’t detect AKDM because blast cells was not enough.

After first CART therapy, two patients had no effect and died, one patient gave up and died. Another 11(100%) patients all achieved CR and MRD negative(CRMRD-) with incomplete blood count recovery(CRiMRD-), and 10/11(90.91%)patients achieved molecular complete response (CRmi) and all of them hadn’t CNSL. ALL these patients received other therapies:three patients received second CART and one then received DLI, TKI was used in eleven patiets based on their AKDM results. To the present, eleven patients remained CRm:two patients stoped use TKI in February and July 2019, one patient received second HSCT in May 2019.

Cytokine release syndrome(CRS) occurred 9/14(64.29%)patients after the first CART:8 grade I, 1 grade III. Only one patient exhibited CAR T-cell-related encephalopathy syndrome (CRES) who had CNSL before CART, and no fetal graft-versus-host disease(GVHD)occurred.

Conclusions: CART therapy for Ph+ALL patients relapsed after HSCT is efficacy

and secure, once they achieved CR after CART therapy, sequencial TKI therapy may prolong the overall survival, leukemia free survival.

Disclosure: Nothing to declare.

Cellular Therapies other than CARs

P113

Abstract already published.

P114 Adoptive Immunotherapy of Refractory Viral Infections after Allogeneic HSCT: An Academic Network Framing the use of an Atmp under Hospital Exemption

Yingying WANG1,2, Marcelo DE CARVALHO1,2, Typhaine PIERRE1, Mélanie GAUTHIER1,2, Véronique DECOT1,2, Laurence CLEMENT3,4, Cécile POCHON1,2,4, Karin BILGER4,5, Jérôme LARGHERO4,6, Hélène ROUARD4,7, Anne FIALAIRE LEGENDRE4,8, Nadine PETITPAIN1,4, Jean Hugues DALLE4,9, Danièle BENSOUSSAN1,2,4

1CHRU de Nancy, Vandoeuvre les nancy, France, 2Université de Lorraine, UMR CNRS 7365, Vandoeuvre les Nancy, France, 3CHU de Bordeaux, Bordeaux, France, 4SFGM-TC, Lyon, France, 5CHRU de Strasbourg, Strasbourg, France, 6Hôpital Saint-Louis, Paris, France, 7EFS, Créteil, France, 8EFS, Saint Denis, France, 9Hôpital Robert Debré, Paris, France

Background: Viral infections are major complications of Hematopoietic Stem Cell Transplantation (HSCT). As efficacy of anti-viral drugs is limited in absence of immune reconstitution and often associated with severe side effects, infusion of Virus-Specific T cells (VSTs) becomes a promising alternative treatment for viral infections and diseases after HSCT. We previously performed a successful phase I/II clinical trial and secondarily obtained an ATMP under hospital exemption authorization from the French regulatory agency for the preparation of VSTs (especially ADV-STs) for all the clinical centers in need. A national group was created under the aegis of the Francophone Society of Bone Marrow transplantation and Cell Therapy (SFGM-TC) to analyze, validate and follow the different requests. We present here the results that have been collected until 2016.

Methods: We previously demonstrated the feasibility of isolating ADV-STs from donors using the IFNg-capture system from Miltenyi biotec followed by immunomagnetic selection on the CliniMACS device (Aissi-Rothé et al, 2010; Qian et al, 2017). Since we obtained the ATMP authorization, we have treated patients with an infusion of polyclonal ADV-STs (n=8) or CMV-STs (n=4) or EBV-STs (n=2) generated by a 6-hour ex vivo stimulation with an appropriate peptide pool (PepT-ADV5 Hexon, PepT-CMV pp65, PepT EBV Select, respectively, Miltenyi Biotec) of leukapheresis collected from their original stem cell donor or more often from third party haploidentical donors, followed by isolation of IFNg producing cells.

Results: We report more than 40 requests to the group, 75% of them in 2019, from different French and Belgium centers followed by 8 refusals, the generation of 14 VST preparations and the infusion of patients (4 months-65 years) with viral infection disease. They received a mean of 0.96 104 CD3-IFNg+ cells/kg (range: 0,042 to 1.436 104). In vivo expansion of transferred VSTs was observed from day 15 to 60 following adoptive transfer infusion associated with viral load decrease or clearance in more than half of the patients. During the 3 month-follow-up, 4 patients experienced failure of the treatment with a persistent increase of viral load. Neither de novo GVHD, nor side effects were observed. Reactivation of grade I aGVHD occurred in 2 patients in the month following infusion and in 3 patients after D45 (grade II and IV). Unfortunately, eight patients died, 4 related to persistent viral infection or disease. However, none of the responders experienced a viral-associated mortality.

Conclusions: Adoptive transfer of VSTs is a feasible and well-tolerated therapeutic option, representing a fast and efficient procedure to achieve reconstitution of antiviral T-cell and decrease or clearance of viral load. However, today this is a last chance therapy and viral load is often over 6.5 log (4 patients) when infusion is performed, not giving VST time to expand and be efficient. The French organization, under the aegis of SFGM-TC, is very secure and reactive and contributes to encourage clinical centers to initiate their request earlier.

Disclosure: Danièle Bensoussan, start up StemInov, CSO

P115 How to Benefit from Exhaustion: patient-derived Inhibited T Cells as a Novel Source of tumor-reactive T Cell Clones

Francesco Manfredi1, Lorena Stasi1, Danilo Abbati1, Sara Mastaglio2, Fabio Ciceri2, Eliana Ruggiero1, Chiara Bonini1,2

1Università San Raffaele, Milan, Italy, 2IRCSS San Raffaele Hospital, Milan, Italy

Background: A notable percentage of blood cancer patients who undergo Allogeneic Hematopoietic Stem Cell Transplantation (alloHSCT) still suffers a dismal prognosis; this therapeutic gap could be filled by Adoptive T cell therapy, but its exploitation is still limited by the incomplete knowledge of tumor-specific T cells dynamics in vivo and by the difficulty to isolate such T cell specificities for therapeutic purposes.

Methods: To visualise and purify tumor-specific T cells ex vivo, we screened circulating cells at 30,60,90,120,180 and 365 days after alloHSCT in N=35 patients affected by blood malignancies with a 18-colour Flow Cytometry panel including fluorescent MHC-I complexes loaded with Tumor-Associated Antigen (TAA) peptides or with a viral peptide. Together, we followed T-Cell Receptor (TCR) clonal dynamics by cell sorting and sequencing.

Results: TAA-Specific T cells were found circulating in the patients’ peripheral blood, as soon as 30 days after alloHSCT. By exploiting high-dimensionality un-biased analytical tools we dissected their phenotype, showing that they express multiple inhibitory receptors at higher levels if compared with either the total CD8 T cell population or viral-specific T cells, independently from major clinical variables (disease status at transplant, disease type, GvHD incidence). The inhibitory signature was the most pronounced 4 months after alloHSCT, and was followed by a substantial contraction of the pool of TAA-specific memory T cells.

We also took advantage of cell sorting to isolate and expand TAA-specific T cells. We established a rapid, highly specific protocol that isolated 24 tumor-specific T cell colonies from n=13/20 screened patients, each one enriched for a single TCR clonotype identified by RNA sequencing. When challenged with peptide-pulsed targets, such ex vivo clones were poorly responsive but when the TCR sequences were cloned into lentiviral vectors and transferred in T cells after Crispr/Cas9 disruption of the endogenous TCR (TCR-edited lymphocytes), cells proved highly efficient and specific in lysing matched pulsed targets (fig.1A). This observation, linked with the previous phenotypic analysis, suggests that TAA-specific T cells are circulating in vivo but are exhausted. We thus tried to broaden the search of Tumor-reactive T cell clones by exploiting the exhaustion signature to purify a T cell subset enriched with anti-tumour reactivities. We sorted T cells from 3 patients affected by Acute Myeloid Leukemia (AML) on the basis of the inhibitory receptors (IR) expression and stimulated both IR+ and IR- cells with matched Leukemic Dendritic Cells (LDC). Serial LDC stimulations promoted the expansion of dominant clones over time in the IR+ but not in the IR- fraction and IR+ T cells proved superior in killing autologous AML blasts in vitro. Again, dominant TCRs were identified in IR+ cultures from the first patient, and TCR-edited lymphocytes efficiently and selectively recognized autologous blasts (fig.1B).

Conclusions: Our findings shed some light on the in vivo dynamics of tumor-specific T cells and introduce two models for the isolation of tumor-specific TCRs, one requiring the knowledge of the target peptide, the other exploiting the IR signature to discover novel tumor specificities.

Disclosure:

Chiara Bonini recieves Resarch funds from Intellia Therapeutics and Immudex, and she´s consultant for Intella Therapeutics, Novartis and Molmed.

The other authors declare. no relevant conflict of interest

P116 Efficient Crispr/Cas9-mediated Inactivation of the Glucocorticoid Receptor for antigen-specific T-cell Immunotherapy

Maria Alvanou1,2, Anastasios Kouimtzidis1,3, Kyriakos Koukoulias1,3, Chrysoula Pantazi1,3, Nikoletta Psatha4, Giorgios Tsiolas5, Alexandros Spyridonidis2, Kostas Stamatopoulos5, Antonios Makris5, Achilles Anagnostopoulos1, Evangelia Yannaki1, Anastasia Papadopoulou1

1George Papanikolaou Hospital, Thessaloniki, Greece, 2University General Hospital of Patras, Patras, Greece, 3Aristotle University of Thessaloniki, Thessaloniki, Greece, 4Altius Institute for Biomedical Sciences, Seattle, WA, United States, 5Centre for Research and Technology Hellas (CERTH), Thessaloniki, Greece

Background: Adoptive immunotherapy (AI) with pathogen-specific T cells (pSTs) is a promising alternative to pharmacotherapy for the treatment of opportunistic infections after allogeneic hematopoietic stem cell (allo-HSCT) or solid organ transplantation. However, clinical implementation of AI is limited to patients receiving either low dose or no steroids, a prerequisite for optimal T-cell function, practically excluding the most susceptible to infections patients from the benefits of AI. Aims. We evaluated the impact of dexamethasone (DEX) on primary T cells and developed a CRISPR/Cas9 system to genetically disrupt the glucocorticoid receptor (GR) in lymphocytes and confer resistance to steroids, in order to ultimately develop steroid-resistant pSTs.

Methods: The impact of DEX on T cell proliferation, phenotype and apoptosis was evaluated in human OKT3 blasts generated by stimulating peripheral blood mononuclear cells through CD3 and CD80 ligation. To inactivate the GR gene, 10 guide RNAs (gRNAs) were prepared to target different genomic sequences corresponding to various domains of the GR (a transcription start site, and exons 2, 3, 4 and 5) and delivered separately into the T2 lymphoblastic cell line using lentiviral vectors. Cells transduced with an “empty” viral vector expressing Cas9 but no gRNA were used as negative control. The resistance of T2 cell line to glucocorticoids was assessed as cell viability by trypan blue exclusion. The on-target inactivation of the GR in T2 cell line was measured by western blot and T7 assay.

Results: A 3-day exposure of OKT3 blasts to DEX negatively impaired the proliferation of stimulated primary T cells and induced early apoptosis over the “no DEX” condition (p=0.001, p=0.01 respectively). These effects correlated with a DEX-induced upregulation of T regulatory cells (p=0.0002). DEX also upregulated PD-1 and CTLA-4, the major coinhibitory molecules in antigen-specific immune responses, over the “no DEX” condition (p< 0.05). Then, in order to render cells steroid-resistant, T2 cells were transduced with lentiviral vectors encoding Cas9 and 10 different gRNAs targeting GR and subsequently incubated in the presence or absence of DEX. T2 cells edited with 7/10 single gRNAs, presented normal proliferation on DEX treatment as contrasted to their untreated counterparts and the empty vector-transduced cells, suggesting functional DEX-resistance. The on-target GR inactivation in T2 cells was confirmed by both western blot and T7 assay. Among tested functional gRNAs, the optimal gRNA was selected for further studies, on the basis of high GR disruption efficiency and low off-target activity.

Conclusions: Overall, we provide a series of gRNAs to CRISPR/Cas9-disrupt the GR and ultimately generate steroid-resistant pSTs in order to offer the benefits of AI to the most vulnerable to infections patients, as those with graft-versus-host-disease receiving high-dose steroids post allo-HSCT.

Disclosure: Funding for this project was provided in part by an EHA Research Grant award granted by the European Hematology Association and in part by the State Scholarships Foundation (I.K.Y.).

P117 Comparison of Outcome post-second Allogeneic Hematopoietic Cell Transplantation Versus Donor Lymphocyte Infusion in Allogeneic Hematopoietic Cell Transplant Patients

Eshrak Al-Shaibani1,2, Jeffrey H. Lipton1,2, Dennis D. Kim1,2, Auro Viswabandya1,2, Rajat Kumar1,2, Wilson Lam1,2, Arjun Law1,2, Zeyad Al-Shaibani1,2, Armin Gerbitz1,2, Ivan Pasic1,2, Jonas Mattsson1,2, Fotios V. Michelis1,2

1Princess Margaret Cancer Centre, Toronto, Canada, 2University of Toronto, Toronto, Canada

Background: Allogeneic hematopoietic cell transplantation (HCT) is potentially curative for a variety of benign and malignant hematological disease, however may be complicated by disease relapse or graft loss/poor graft function. Both second allogeneic HCT and donor lymphocyte infusions are utilized in the management of both complications. The purpose of the present study is to compare outcomes following both interventions in a single center cohort of patients transplanted over the last five years.

Methods: We retrospectively investigated 65 patients in total, 34 (52%) underwent second allogeneic HCT and 31 (48%) received donor lymphocyte infusions (DLI), from June 2011 to November 2018.

Results: Median patient age at the time of the post-transplant intervention was 51 years (range 19-72). Second HCT was performed for disease relapse in 11 patients (5 of which were transplanted for AML) and for graft failure (GF) in 23 patients (primary in 6 and secondary in 17 patients). Donors for second HCT were related (n=10), unrelated (n=18) and haploidentical (n=6), the same donor was used in 20 (59%) patients. At second HCT, the HCT-CI was 0-2 for 22 patients (65%) and ≥3 for 12 patients (35%). Concerning DLI patients, this was performed for relapse for 17 patients (8 of which were transplanted for AML) and for secondary GF or chimerism loss in 14 patients. Donors for DLI were related for 13 patients, unrelated for 16 patients and haploidentical for 2 patients. KPS at first DLI was 90-100% for 20 patients (65%) and 70-80% for 11 patients (35%). Median number of DLI administered was 2 (range 1-11).The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (20)

[Figure 1: Overall survival with second transplant vs donor lymphocyte infusion for relapsed patients]

Median follow-up of survivors following intervention was 18 months (range 3-66 months). Univariate analysis demonstrated 2-year overall survival (OS) of 50% (95%CI 37-62%) for the entire cohort, while 2 year OS was identical between all second transplant patients and DLI patients (50% for both groups, p=0.9%). For second HCT patients, 2-year OS was 82% (95%CI 45-95%) and 35% (95%CI 17-54%) for relapse as an indication versus GF respectively (p=0.01). For the DLI patients, 2-year OS was 44% (95%CI 20-66%) and 56% (95%CI 27-78%) for relapse as an indication versus GF/loss of chimerism respectively (p=0.64). For disease relapse as an indication, second HCT was significantly superior to DLI (p=0.03, Figure 1). Multivariable analysis for second HCT patients demonstrated age (HR 1.04, 95%CI 1.00-1.07, p= 0.03) and donor type (HR 0.17 for related donor, 95%CI 0.04-0.75, p=0.02) to independently predict OS. For DLI, multivariable analysis demonstrates KPS at the time of the first dose of DLI as the predominant predictor of survival (HR 0.89, 95%CI 0.82-0.96, p=0.002).

Conclusions: Second allogeneic HCT demonstrates superior survival when performed for disease relapse post-transplant compared to DLI. In contrast, second HCT for graft failure results in poor long-term survival. Second allogeneic HCT should be preferred as a reasonable treatment option for patients that relapse post-transplant and achieve pre-second HCT remission.

Disclosure: Nothing to declare.

P118 Automated Application for Depletion of Tcrab+, CD19+ and CD45RA+ Cells from Apheresis Products using the Clinimacs Prodigy®

Julia Dzionek1, Carina Thießen1, Felix Hebbeker1, Stephanie Soltenborn1, Joanna Justyna Stenzel1, Burgund Kauling1, René Meißner1, Nikolas Kaltz1, Kirsten Langeveld1, Michaela Malchow1, Mario Assenmacher1, Andreas Bosio1, Eleni Papanikolaou1,2

1Miltenyi Biotec B.V. & Co. KG, Bergisch Gladbach, Germany, 2National and Kapodistrian University of Athens, Athens, Greece

Background: Major complications of allogeneic stem cell transplantation are GvHD and infections. Ex-vivo T cell depletion (TCD) can effectively prevent GvHD, however it may prolong immune reconstitution and increase the risk of infections. Depletion of TCRab+ T cells combined with the transfer of CD45RA- donor memory T cells may ameliorate the infection risk and simultaneously decrease the risk of GvHD. Here, we report the development of a single, automated manufacturing process on the CliniMACS Prodigy® to generate personalized grafts providing a TCRab-depleted stem cell product and a memory T cell product.

Methods: Currently, the combined depletion of TCRab+/CD19+ cells and the depletion of CD45RA+ cells exist as two separate applications on the CliniMACS Prodigy. The novel integrated CliniMACS Prodigy LP-TCRab-19-45RA depletion process merges these two strategies in one application performed in one tubing set, namely CliniMACS Prodigy TS 320. Depending on the desired cell composition of the graft, the user can choose to perform either:

· sequential depletion of CD45RA+ and TCRab+ cells with or without simultaneous depletion of CD19+ cells,

· a depletion of TCRab+ cells with or without simultaneous CD19+ cells or

· a CD45RA+ cell depletion only.

All TCRab depletion cases (with or without simultaneous depletion of CD19+ cells) can be performed in normal or large scale, depending on the number of total WBC, TCRab+ and CD19+ cells. The memory T cell product and the stem cell product are collected in separate bags and can be combined to a single cell product, according to each patient’s need (personalized graft).

The new application software effectively depletes 2.4x109 CD45RA+ cells from up to 6x109 total WBC, and 48x109 total TCRab+ cells plus 15x109 total CD19+ cells from up to 120x109 total WBC.

Results: In-house evaluation runs (total n = 41, 10 mobilized and 31 non-mobilized apheresis products) resulted in comparable values for depletion, yield, recovery, and WBC viability of the target products regardless of the application case performed. The mean log depletion achieved for the TCRab±CD19-depleted products (n = 41) was 4.5 (range 3.5-5.2) for TCRab+/CD45RA+ cells and 3.4 (range 2.6-4.3) for CD19+ cells with a stem cell viability over 90% and mean yield of 81%. In the CD45RA-depleted products (n=31) a mean log depletion of 5.4 (range 3.8-6.4) for TCRab+/CD45RA+ cells was obtained.

The duration of CD45RA depletion takes between 1.5-1.7 hours, while the duration of TCRab±CD19 depletion ranges between 5.1-8.3 hours. Finally, the combined TCRab±CD19/45RA depletion needs 6.7-10.3 hours to complete, depending on total cell numbers. Importantly, input of a defined process end time is possible.

Effective quality control panels and express modes for MACSQuant® Flow Cytometers enable easy and accurate monitoring of the entire cell manufacturing process.

Conclusions: In summary, the novel automated CliniMACS Prodigy LP-TCRαβ-19-45RA depletion process is capable to deplete CD45RA+, TCRab+ and CD19+ cells efficiently from apheresis products with a mean yield of 81% for CD34+ cells. The performance verification and submission to an European notified body for CE marking as medical device application are the important next steps.

Clinical Trial Registry: n/a

Disclosure: n/a

P119

Abstract already published.

P120 Good Response Rates of WJ-MSC, Comparable to BM-MSC, in the Treatment of Refractory GVHD

Sílvia Torrents1, Laura Alonso2, Joaquim Vives1, Luciano Rodríguez1, Georgina Morón-Cazalilla3, Izaskun Elorza4, Maria Luz Uria2, Maria Isabel Benítez2, Rocío Parody5, Guillermo Ortí2, Maria Trabazo3, Jesús Fernandez-Sojo1, Margarita Codinach1, Laura Medina1, Isabel Badell4, Cristina Diaz de Heredia2, Sergi Querol1

1Banc de Sang i Teixits, Barcelona, Spain, 2Hospital Vall d´Hebron, Barcelona, Spain, 3Santa Creu i Sant Pau Hospital, Barcelona, Spain, 4Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, Spain, 5ICO - Hospital Duran i Reynals, Barcelona, Spain

Background: Acute graft-versus-host-disease (aGVHD) is one of the main complications derived from an allogeneic hematopoietic progenitor cell transplant (HPCT). First line therapy is based on the use of steroids but many patients are refractory. Due to the immunomodulatory characteristics of multipotent mesenchymal stromal cells (MSC) this cell type have been used with success in the treatment of refractory aGVHD. Wharton Jelly’s (WJ) is a new source of MSC with advantages for large-scale production and standardization. The aim of this study is to evaluate the ability of WJ MSC’s to improve refractory aGVHD compared to MSC’s obtained from Bone Marrow (BM).

Methods: Retrospective study of patients with refractory aGVHD treated with MSC produced at Banc de Sang I Teixits between (2017-2019). All patients received at least two doses of MSC (1E6 MSC/kg of patient body weight per dose). To obtain and process the cells, an approved IND was followed in our production facilities using BM-MSC’s (PEI 13-081) or WJ-MSC’s (PEI 16-017). Patients were treated in 4 hospitals of Barcelona area, after receiving corticosteroids and second or further lines of alternative drugs. Upon request by transplant center, MSC samples were released for a therapy scheduled for infusion on days 1, 4, 11 and 18 using a compassionate schema.

Results: Eighteen patients (12 pediatric and 6 adults) have been treated during this period. Table 1 shows diagnosis, graft source, GVHD grade and organ involvement and MSC source. The first MSC infusion was performed on median 5 months after the onset of the GVHD (range 0.6 to 46). There were no adverse reactions related to the MSC infusions. Two patients died before day 7 due to sepsis and viral infection not related to the procedure. They received only 2 doses of therapy and were not included in the survival analysis. Over 16 patients, five patients died due to GVHD progression, relapse or infection. Remarkably, ten patients (63%) have responded to treatment, and five (31%) achieved complete response. Responders achieved high overall survival. The median response time was 14 days after the first MSC infusion (range, 7-28 days). Evaluating performance status (Karnofsky/Lansky scale) median improvement was in day 21 (range, 7-49 days). One responder died later on time, due to sepsis after achieving CR. According to the source of MSC, 7 of 12 evaluable patients that were treated with WJ-MSC responded to treatment (58%), comparable to 3 of 4 from BM-MSC (75%).

Conclusions:

MSC treatment resulted in a safe procedure with a response rate of 63% of heavily pretreated patients. WJ-MSC showed similar results than BM-MSC. These results show the feasibility and support the proposal of a prospective trial in order to demonstrate efficacy in this setting.

DiagnosisAcute leukaemia (12) Non malignant diseases (6)
Graft sourceRelated (5) Unrelated (9) Cord blood (4)
GVHD gradeI (2) II (1) III (8) IV (7)
Organs InvolvedSkin (9) Gut (15) Liver (7)
MSC sourceWharton Jelly (12) Bone Marrow (6)

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[Table 1]

Disclosure: Nothing to declare.

P121 An “all in one” T-cell Product from non-transplantable Cord Blood Units for Virus- and leukemia-specific T-cell Immunotherapy

Kyriakos Koukoulias1,2, Anastasia Papadopoulou1, Anastasios Kouimtzidis1,2, Damianos Sotiropoulos1, Minas Yiangou2, Achilles Anagnostopoulos1, Evangelia Yannaki1, Panayotis Kaloyannidis3

1George Papanikolaou Hospital, Thessaloniki, Greece, 2Aristotle University of Thessaloniki, Thessaloniki, Greece, 3King Fahad Specialist Hospital Dammam, Dammam, Saudi Arabia

Background: Leukemic relapse and opportunistic viral infections represent the major causes of morbidity and mortality post allogeneic hematopoietic cell transplantation (allo-HCT). T-cell immunotherapy with chimeric antigen receptor T-cells (CAR-Ts) is currently the spearhead of research in refractory hematological malignancies, however, CAR-Ts for myeloid leukemias lag well behind CAR-Ts for B-cell lymphoid malignancies, mainly due to the lack of an appropriate, targetable antigen. On the other hand, while immunotherapy with non-genetically engineered virus-specific T cells has been shown to successfully control viral infections post-allo-HCT, single-epitope leukemia-specific T-cells (Leuk-STs) targeting the less immunogenic leukemia-associated antigens (LAAs) have met limited clinical success. Aim. By adapting our previously developed protocol of generating multivalent Leuk-STs, targeting multiple epitopes of various leukemic antigens by stimulation with overlapping peptides spanning the whole proteins, we here aimed to generate a non-engineered, “all-in-one”, T-cell product from Non-Transplantable Umbilical Cord Blood Units (NT-UCBUs), called LEukemia-VIrus-specific T-cells (LEVIS), which simultaneously targets four viruses and two common LAAs.

Methods: Matured CD34+-derived dendritic cells from NT-UCBUs were stimulated with both leukemic [Wilms tumor protein (WT1) and Preferentially Expressed Antigen in Melanoma (PRAME)] and viral [EBNA1, LMP2 and BZLF1 (EBV); IE1 and pp65 (CMV); Hexon and Penton (AdV) and Large-T and VP1 (BKV)] pepmixes and used to “educate” autologous, naive T-cells.

Results: By reclaiming disqualified for allo-HCT NT-UCBUs and using our approach, we have been consistently obtaining clinical doses of LEVIS (CD3+ cells: 1.01±0.2x108). The resultant T-cell products are polyclonal, containing both CD4+ and CD8+ T-cell subsets (39±2% and 50±2%, respectively), expressing effector memory (CD45RA-/CD62L-: 47.36±5%) and effector memory RA markers (CD45RA+/CD62L-: 48.50±4%), while containing insignificant amount of naïve and regulatory (CD4+/CD25high) T cells. LEVIS demonstrated high specificity against all targeted antigens [spot-forming units (SFC)/2x105 cells: CMV: 311±149, EBV: 319±111, BKV: 245±122, AdV: 432±32, Leuk: 553±257], similar to that conferred by Leuk-STs alone, suggesting successful “training” of naïve T cells and lack of antigen competition by the addition of immunodominant viral antigens. Importantly, LEVIS demonstrated low expression levels of Programmed cell Death protein-1 (PD-1) and barely detectable Cytotoxic T-Lymphocyte Associated Protein-4+ (CTLA-4), which remained stable throughout the culture, suggesting that persistent antigen exposure did not impair their Th-1-polarized function in vitro, an effect that could be translated into anti-leukemic and antiviral response after infusion.

Conclusions: Overall, by “recycling” NT-UCBUs, we provide the potential for future banking of LEVIS, to serve as third-party, “off-the-shelf”, multipotent T-cell products, thus further optimizing adoptive immunotherapy and improving the outcome of allo-HCT.

Disclosure: Nothing to declare.

P122 Clinical Success of Granulocyte Transfusions in Adult Neutropenic Patients after Chemotherapy and/or Allogeneic Transplantation - Time Matters!

Kira Inkari Thies, Michael Kramer, Friedrich Stölzel, Martin Bornhäuser, Johannes Schetelig, Simone von Bonin, Ralph Schneider, Kristina Hölig

Technische Universität Dresden, Dresden, Germany

Background: For decades, granulocyte transfusions (GTX) have been performed to treat neutropenic haematological patients with infectious complications. Nevertheless, the clinical efficacy of this cellular therapy is remaining controversial.

Methods: We performed a risk factor analysis in a large cohort of patients who received GTX between 2004 and 2014 at the University Hospital Dresden. Demographical data, diagnosis and outcome of the patients were registered. Among other parameters, type and state of the infection, dosage of the transfused granulocyte concentrates, and adverse effects had been recorded during each GTX cycle. GTX during an active infection were considered as “therapeutically” and GTX in patients who previously had survived life-threatening infections were considered as “prophylactically”. We evaluated overall survival and day-30-mortality from infection according to several risk factors. Treatment-cycle- or product-related variables were modeled as time-dependent variables and analyzed with Cox regression with time-dependent covariate. Cumulative incidences of infection related deaths were estimated according to the methodology of Gray. Competing risk was death from other causes than infection. The cause specific hazard for death due to infection was estimated with Cox regression.

Results: A total of 187 patients received 886 transfusions within 232 treatment cycles. The mean dose was 8.05 ∙ 1010 neutrophil cells (SD =2.5) per transfusion. In 194 of 232 cycles (84 %) granulocytes were transfused therapeutically, in 37 cycles (16 %) prophylactically.

Patient-related factors had impact on clinical outcome. State of the infection appeared to be the most important factor: Patients with septicemia had significantly lower treatment success than patients with localized infections with a significantly lower Overall survival (HR 2.4; CI: 1.68 - 3.52; p < .001) and a 4.8-fold higher cause specific hazard for infection-related death within 30 days after the first GTX (CI: 2.48 - 9.32; p < .001). Analysis of surrogate parameters for the severity of infections supported these findings (e.g. patients in ICU, patients requiring ventilation support, bacterial versus mycotic infections or a combination of both).

Among transfusion-related factors, early administration of GTX was favorable for therapeutic success. Patients with prophylactic GTX had a significantly lower 30-day-infection-mortality than patients with therapeutic GTX (HR 0.14; CI: 0.02 - 0.94; p = .044) and a slightly better overall survival (HR 0.71; CI: 0.38 - 1.27; p = .238). Patients who received ≥ 4∙1010 granulocytes per transfusion had a significant lower 30-days-infection-related mortality (HR 0.76; CI: 0.63 - 0.92; p = .005). Transfusion reactions were seen in 60 out of 886 (7 %) transfusions. Our analysis revealed no difference in the frequency of side effects with respect to the amount of granulocytes per transfusion (HR 0.95; CI: 0.67 - 1.34; p = .756).

Conclusions: Our data indicate that patients receiving GTX at an early stage of their infection seem to particularly benefit from this treatment. High dose GTX seem to be advantageous, In our cohort, GTX proved to be a safe approach without any severe side effects.

Nevertheless, these retrospective data are limited and should be validated in further prospective controlled studies.

Disclosure: Nothing to declare.

P123 Impact of long-term Cryopreservation of Autologous Hematopoietic Stem Cells Products

Judith Desoutter, Aline Regnier, Christèle Ossart, Alexis Caulier, Véronique Harrivel, Marie Noelle Lacassagne, Jean Pierre Marolleau

CHU Amiens Picardie, Amiens Cedex, France

Background: Freezing and storage of hematopoietic stem cells (HSC) graft are keys steps of therapeutic intensification process by autograft. No maximum storage period is defined in literature and less data are available concerning the quality of graft cryoconserved for a long duration. Now a day, only the notion that storage duration more than 15 years may be potentially harmful was advanced by 2014 SFGM-TC guidelines. (Calmels and al, Pathologie biologie 2014; 62: 221-225)

Methods: Fifty seven autologous grafts with long term storage (more than 5 years) were thawing in our study and were:

- evaluated by a quality control using Stem-Kit (Beckman Coulter, France) by flow cytometer including: viability/total nucleated cells count (TNC), viability/number of CD34+ cells, hematopoietic reconstitution evaluation (CFU-GM)

- compared with 60 short-term storage autologous grafts (less than 2 years) thawing routinely in laboratory.

Results: By comparison with routinely thawing graft quality criteria, we observed that CD34+ yield (p< 0.0001), TNC yield (p = 0.037) and number of CFU-GM/kg (p< 0.0001) were negatively impacted, based on lengthening of storage period. Moreover, we highlighted a significatively decreased of clonogenicity linked with increase graft storage duration (p=0.02).

Conclusions: Autologous graft long-term cryopreservation has a clear impact on product quality, in view of decreased CD34+ cells as well as CSH functionality in vitro. No national consensus defining cryopreservation modality and grafts storage, capable of influencing positively or negatively grafts quality, notably during long term conservation.

Disclosure: Nothing to declare.

P124 Optimizing Lentiviral Vector Transduction to Gene Modify Cord Blood CD8+ T Cells for off-the-shelf Adoptive Cell Therapy to Treat Cancer

Vania Lo Presti1, Ester Dunnebach1, Maud Plantinga1, Annelisa Cornel1, Jurgen Kuball1, Jaap Jan Boelens2, Niek van Til *1,3, Stefan Nierkens *1,4

1UMC-Utrecht, Utrecht, Netherlands, 2MSKCC, New York, NY, United States, 3AVROBIO Inc, Cambridge, MA, United States, 4Princess Máxima Center for Pediatric Oncology, Utrecht, Netherlands

Background: Adoptive T cell therapy utilizing autologous T cells has shown promising results for cancer treatment. However, the limited numbers of tumor associated antigen (TAA)-specific T cells and the functional aberrancies due to disease progression or treatment remain factors that may significantly limit the success of the therapy. The use of allogeneic T cells as an off-the-shelf therapy overcomes these issues, but requires gene-modification to induce a robust and specific anti-tumor effect. Umbilical cord blood (CB) might be particularly suited for this purpose; CB T cells are readily available in cord blood banks, show low toxicity, high proliferation rates and increased anti-leukemic effect upon transfer. Moreover, CB T cells can be used as combinational therapy in the hematopoietic cell transplantation setting to prevent minimal residual disease, relapses, and completely eradicate all tumor cells. However, combining anti-tumor gene modification and preserving advantageous immunological traits of CB T cells represents a major challenge for the harmonized production of T cell therapy products.

Methods: CB CD8+ T cells were isolated from fresh CB donors, subsequently expanded and activated. CB CD8+ T cells were transduced with lentiviral vectors (LV) expressing GFP and WT1-TCR, in order to compare methods, culture media, promoter strength and use of transduction enhancers. Analysis of immune-phenotype was performed in CB CD8+ T cells and PB CD8+ cells after isolation, expansion and transduction.

Results: In this manuscript we describe an efficient protocol to expand and transduce CB CD8+ T cells using LV, achieving an efficiency up to 83% of transduced cells. The protocol was established by optimizing the timing of LV treatment, selection of culture media, and application of different promoters. We confirmed LentiBOOST as a non-toxic transduction enhancer, however its use decreased the proliferation capacity of the T cells. Finally, we show that CB CD8+ T cells were more amenable to LV transduction than PB CD8+ T cells, and that the immune phenotype of the two cell sources were remarkably different with respect to the expression of inhibitory receptors and maturation markers.

Conclusions: We show an efficient method of gene modification of CB CD8+ T cells using LV, which is especially useful for off-the-shelf adoptive cell therapy products for cancer treatment, especially in post hematopoietic cell transplantation setting.

Disclosure: Nothing to declare.

P125 Donor Lymphocyte Infusion after Allogeneic Hematopoietic Stem Cell Transplantation. Single Centre Experience

Isabel Iturrate, Analys Ruiz, Sara Martínez, Natalia García-León, Mercedes Royg, Ángela Figuera, Adrián Alegre, Beatriz Aguado

Hospital Universitario La Princesa, Madrid, Spain

Background: Donor Lymphocyte Infusion (DLI) is often used to treat relapsed haematological malignancies after allogeneic stem cell transplantation. DLI is an immune-mediated therapy, mainly driven by the antitumor effect of donor T cells which can, in part, augment the graft-versus-tumor effect. However it can sometimes induce fatal adverse events such as severe graft-versus-host-disease (GVHD) and infectious complications.

Methods: We retrospectively analyzed 72 patients who received DLI for treatment of relapsed haematological malignancies, who had been allotransplantated in our centre between 1994 and 2018. Median age of 43 years old (range 16-70) at the time of DLI. Underlying diseases treated with DLI included chronic myeloid leukemia (CML) (n=20), acute myeloid leukemia (AML) (n=20), acute lymphocytic leukemia (ALL) (n=11), Hodgkin lymphoma (HL) (n=8), non Hodgkin lymphoma (NHL) (n=7), myelodysplastic syndrome (MDS) (n=5) and multiple myeloma (MM) (n=1). Fifty-nine patients received HLA-matched sibling donor, 2 haploidentical related donor and 11 matched unrelated donor transplant. Conditioning regimen was mieloablative in fifty-three patients, and reduced intensity conditioning in nineteen patients. All patients received DLI as treatment for relapsed disease after allogenic transplantation. In the present study we analyse response rate, graft-versus-host-disease (GVHD), progression free survival (PFS) and overall survival (OS).

Results: Our patients received a median of 3 infusions (range 1-5). The median number of infused CD3+ cells was 0.5x108/kg (range 0.1x108/kg to 2.84x108/kg). Sixty-eight percent of patients received dose-escalation DLI. Patients with low disease burden only received DLI. Thirty-nine percent received DLI-associated therapy (chemotherapy, radiotherapy, tyrosine-kinase inhibitors).

From the sixty-three patients eligible for evaluation, 35 (56%) got clinical benefit (CML n=14, ALL n=6, AML n=6, HL n=5, MDS n=2 NHL n=2). Progression free survival was higher in CML, with a median of 132 months, followed by NHL (84 months). Acute graft-versus-host-disease developed in 15% of the patients (5 patients grades I-II, the other 5 grades III-IV). Two patients died from acute hepatic GVHD. Chronic GVHD developed in 22% (6 cases limited, 9 extend). One patient died from chronic pulmonary GVHD.

With a median follow up of 16 years, median progression-free survival was 120 months [IC 95% 84.51-155.49] for the whole series. There are substantial survival differences according to underlying diseases, with a better survival rates for CML and LH.

Conclusions: Inmunotherapy with DLI is an attractive strategy for relapsed patients after allogeneic transplantation. In our experience, patients with CML have more clinical benefit, with a response rate of 70%, similar to published. DLI response in other pathologies is lower, although it can be useful in association with other therapies. However, further studies are needed to develop strategies to reduce toxicity and enhance anti-tumor activity.

Disclosure: Nothing to declare.

P126 Case Report: Chronic Active epstein-barr Virus Infection (CAEBV) Controlled by Allogeneic Hematopoietic Stem Cell Transplantation (alloHSCT) and Transfusion of EBV-specific T-cells

Elisabeth Meedt1, Daniela Weber1, Britta Eiz-Vesper2, Britta Maecker-Kolhoff3, Agnes Bonifacius2, Klaus Schwarz4,5, Myriam Lorenz4, Susanne Delecluse6,7, Henri-Jacques Delecluse6,7, Ernst Holler1, Wolfgang Herr1, Matthias Edinger1, Daniel Wolff1

1University Medical Center Regensburg, Regensburg, Germany, 2Hannover Medical School, Hannover, Germany, 3Hannover Medical School, Hannover, Germany, 4University of Ulm, Ulm, Germany, 5German Red Cross Blood Service, Baden-Wuerttemberg-Hessen, Ulm, Germany, 6German Cancer Research Center (DKFZ), Heidelberg, Germany, 7German Center for Infection Research (DZIF), Braunschweig, Germany

Background: Chronic active Epstein-Barr virus infection (CAEBV) is one of the Epstein-Barr virus (EBV)-positive lymphoproliferative diseases. It is a rare and often fatal complication of EBV infection. In CAEBV, EBV-infected B-, T- or NK-cells clonally proliferate and infiltrate multiple organs, leading to their failure. At present, allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only curative therapy. Other treatments such as high-dose systemic corticosteroids or ganciclovir combined with either histone deacetylase inhibitors or proteasome inhibitors (e. g. bortezomib) may temporarily reduce systemic toxicity and allow the patient time to receive a transplant.

Methods: We report a case of T-cell-type CAEBV in a 27-year-old female caucasian patient with severe skin, neurological, hepatic and pulmonary involvement.

Results: After several therapeutic approaches including high-dose systemic steroids, ganciclovir combined with bortezomib and rituximab had failed with EBV encephalitis requiring mechanical ventilation, third-party EBV-specific T-cells were administered and clinical symptoms resolved, while EBV viremia persisted. Subsequently, alloHSCT was performed from an HLA-matched unrelated donor after conditioning with antithymocyte globulin (ATG), fludarabine and treosulfan followed by an alpha-beta T-cell depleted and EBV-specifc T-cell enriched peripheral stem cell graft and GvHD prophylaxis with everolimus. Intriguingly, the viremia cleared after administration of ATG in alloHSCT setting. When the virus reactivated again in persisting host T-cells everolimus was tapered and viremia could again be controlled by transfusion of donor derived EBV-specific T-cells. Until now, no underlying immunodeficiency was found in the patient while complete host genome DNA and EBV genome sequencing is pending.

Conclusions: Treatment with EBV-specific T-cells from a third party donor followed by alloHSCT from an EBV seropositive donor is an effective therapeutic approach in CAEBV. As EBV-viremia was cleared after the administration of ATG in the alloHSCT setting for the first time in the patient, ATG might be further analysed as a potential treatment option in T-cell-type CAEBV due to its depletive activity on T-cells.

Disclosure: Nothing to declare.

Chronic leukaemia and other myeloproliferative disorders

P127 Incidence of late Relapse after Allogeneic Stem Cell Transplantation for Myelofibrosis

Isik Kaygusuz Atagunduz, Anita Badbaran, Gaby Zeck, Christine Wolschke, Francis Ayuk, Maximilian Christopeit, Nicolaus Kröger

University Hospital Eppendorf, Hamburg, Germany

Background: Despite advances in transplantation procedures and significant prolongation in survival, relapse following allogeneic hematopoietic stem cell transplantation (SCT) for myelofibrosis (MF) remains a significant issue. Most relapse occurs during the early period of allogeneic SCT. We aimed to analyze the clinical characteristics of the patients with late relapse following allogeneic SCT.

Methods: In this cross-sectional study we retrospectively evaluated the files of 259 patients with myelofibrosis transplanted between 1994 and 2015 for late relapses. Late relapse was defined as the relapses later than first five years of stem cell transplantation (SCT). Study patients were grouped according to their relapse status under follow-up after five years. Group A consisted of patients with a late relapse. Patients under long term follow-up after five years with no relapse consisted Group B. Clinical and laboratory parameters of late relapse were investigated.

Results: A total of 94 patients (M/F=55/39, 58.5 vs. 41.4%, respectively) out of 259 MF transplant patients were identified with a median follow-up of 9.15 years (range, 5.12-19.61). Median age at transplantation of the whole study population was 56 (range;29-75). Sixty two patients (66%) had primary MF (PMF), 18 (19.1%) had post polycythemia vera (PV) and 14 (%14.9) had post essential thrombocythemia (ET) myelofibrosis. Thirteen patients (M/F=7/6) experienced (12%) late molecular (n=6) or hematological (n=6) relapses at a median of 7.1 years (range, 5.02-10.20). Eighty- one patients (M/F=48/33) with a median follow-up of 8.76 years (5.02-19.61) did not experienced relapse. Median age at transplant was similar in both groups (Group A vs Group B: 55 (36-73) vs. 57 (29-75)). Although, numerically smaller, median time from diagnosis to transplantation, 20 months (3-100) in Group A and 13 months (1-353) in Group B, had no effect on relapses. Other clinical and laboratory parameters analyzed were not associated with a significantly higher risk of late relapse. Relapse patients received either DLI (n=9) and/or second transplantation (n=4). Of those 61.5 % achieved again full donor cell chimerism and/or molecular remission. After a median follow up of 105 months (range,4-236) of the relapsed patients the 2 years PFS and overall survival is 92.3% and 84.6%, respectively.

Conclusions: In this large MF group we observed late molecular or hematological relapses. DLI and second SCT are effective to induce remission. Early detection of minimal residual disease (MRD) and therapy adjustment resulted in full chimerism and negative MRD status. Our results implicate the importance of close monitoring of MF patients even after 5 years post allograft.

Disclosure: Nothing to declare.

P128 Hematopoietic Stem Cell Transplantation in Myelofibrosis: The Experience of Three University Transplant Centres in Rome

Giulia Galassi1, Patrizia Chiusolo2, Raffaella Cerretti3, Walter Barberi1, Luisa Quattrocchi1, Ursula La Rocca1, Federica Sorà2, Valentina Rossi3, Giovanni Manfredi Assanto1, Mattia Brescini1, Roberto Ricci1, Roberto Latagliata1, Massimo Breccia1, William Arcese3, Andrea Bacigalupo2, Simona Sica2, Anna Paola Iori1

1Università Sapienza, Rome, Italy, 2Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy, 3Università Tor Vergata, Rome, Italy

Background: Myelofibrosis (MF) is a rare BCR-ABL negative myeloproliferative neoplasm, which can only be cured by Hematopoietic Stem Cell Transplantation (HSCT). Because of transplant related mortality (TRM) and morbidity, HSCT is reserved only to patients aged < 70 years with intermediate-2 or high risk MF, according to IPSS or DIPSS, or intermediate-1 with biological high-risk characteristics. Recently, Myelofibrosis Transplant Scoring System (MTSS) has been proposed in order to estimate the transplant risk. The aim of this analysis was to evaluate the outcomes of patients transplanted for MF in three University Transplant Centres in Rome and to verify the accuracy of MTSS in this population.

Methods: We retrospectively analysed 83 MF patients transplanted in Rome at Policlinico Umberto I (25 pts), Policlinico Tor Vergata (23 pts) and Policlinico Agostino Gemelli (35 pts), between 1986 and 2019 (75% of HSCT performed after 2012). Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method. The log-rank test was used to compare risk factors categories. Cumulative incidence (CI) was used to calculate TRM, Relapse Risk (RR), graft failure (GF) and GVHD. A modified MTSS not including ASXL1 mutation was used (ASXL1 mutation data available for only 2 patients).

Results: Median age was 54 years (range 21 - 72). 44%, 28% and 28% of patients received transplant from HLA-identical related, unrelated and haploidentical donors, respectively. Peripheral hematopoietic stem cells were used in 59% of patients. RIC regimens (mainly Thiotepa, Busulphan and Fludarabine-based) were employed in 70%. Forty patients had been previously treated with Ruxolitinib: 27 patients responded or showed disease stability; 13 patients progressed during treatment. Modified MTSS was evaluated in 47 patients, for whom driver mutation data was available. The risk was low in 12 (25%), intermediate in 21 (45%) and high in 14 (30%) patients. Five-year OS was 60%. Features associated to a better OS were: Karnofsky ≥90% (p=0.04), spleen< 22 cm (p=0.04) and cGVHD (p=0.013). A trend to a worse OS was observed in patients who had progressed while in treatment with Ruxolitinib. At 5 years, DFS and RR were 56% and 22%, respectively. CMV and EBV reactivations were associated to an increased RR. TRM was 12% at 100 days, 20% at 1 year and 28% at 5 years. CI of GF at 100 days was 6.5%, with a higher risk trend for HSCT performed before 2012 and donor/recipient sex mismatch (F/M). Acute GVHD CI was 38% (III-IV grade 11% of patients). Two-year CI of cGVHD was 45%; mild and moderate cGVHD was observed in 82% of cases. Transplant from sibling donor and MAC regimen were associated to an increased risk of cGVHD. The 2-year OS according to modified MTSS was: 100% for low, 85% for intermediate and 50% for high risk (p=0.01).

Conclusions: In our experience, better outcome was observed for patient < 57-year-old, with higher PS, not progressing during Ruxolitinib treatment before HSCT. Modified MTSS was a robust tool for the evaluation of transplant risk.

Disclosure: Nothing to declare.

P129

Abstract already published.

P130 CML Relapse after Allogeneic HSCT: Survival, Treatment Efficacy and Prognostic Factors for Outcome

Dunja Kampelmann, Dietrich W. Beelen, Rashit Bogdanov, Vesna Klisanin, Michael Koldehoff, Lambros Kordelas, Rudolf Trenschel, Markus Ditschkowski

University Hospital Essen, Essen, Germany

Background: Tyrosine kinase inhibitors (TKI) have fundamentally changed the therapeutic concept in CML leading to excellent outcome. Although allogeneic stem cell transplantation (HSCT) is currently only required for a limited number of patients (pts) post-transplant relapse remains a major challenge.

Methods: Retrospective single center long-term evaluation of overall survival (OS), relapse-free survival (RFS) and the incidence of CML relapse after allo-HSCT. Analysis of OS and leukemia-free survival (LFS) among relapsed transplant recipients compared to non-relapse pts, review for prognostic factors and evaluation of response to relapse treatment. Data on 488 eligible CML pts transplanted between January 1996 and September 2015 were analyzed. At time of transplant 80% of all pts were in chronic, 12% in accelerated and 8% in blast phase. For the comparison between OS in pts with and w/o relapse after HSCT only survival longer than 15 months post-transplant (n=352) was considered to minimize lead-time-bias by landmark analysis. Cox regression was used to ascertain influencing factors for RFS.

Results: Median follow-up in the cohort was 129 months, 25% (n=120) of all transplant recipients sustained relapse with a median onset of 15 months after HSCT. Cumulative incidences (CI) of relapse were 13%, 23%, 26%, 28% and 30% after 1, 3, 5, 10 and 15 years post-transplant. RFS was assessed 67%, 53% and 47% after 1, 5 and 10 years post-transplant. Multivariate analysis of RFS proved advanced disease stages (> 1. chronic phase) at time of HSCT to be an independent adverse prognostic factor (p=0,005) whereas chronic GvHD showed only significant impact in univariate analysis. Based on landmark analysis, OS could be demonstrated to be significantly higher in transplant recipients w/o relapse (p=0,042). Among relapsed pts OS was significantly worse in hematologic compared to molecular or cytogenetic relapse (p=0,018; p=0,012). In 72% of pts with CML-relapse long-term remission could be induced resulting in a median progression-free survival of 98 months. For molecular relapse 15-year OS was 92% after discontinuation of immunosuppression, 100%, 89% and 80% after treatment with DLI, IFN or TKI. For cytogenetic relapse 15-year OS was 56% after discontinuation of immunosuppression and 100% after treatment with DLI, IFN or TKI. Hematologic relapse resulted in a 10-year OS of 100% after treatment with IFN and 67% after TKI therapy.

Conclusions: To achieve favorable RFS in CML, allo-HSCT should be applied in non-advanced disease stages. However, even in case of relapse after HSCT remissions with favorable long-term survival can be induced in particular when relapse is diagnosed as molecular or cytogenetic CML recurrence.

Disclosure: Nothing to declare.

P131 Chronic Myeloid Leukemia: Allogeneic Hemopoietic Stem Cells Transplantation in the Era of Tyrosine Kinase Inhibitors

Elena Morozova, Yuliya Vlasova, Mariya Barabanshikova, Kseniya Afanasieva, Nikolay Mamaev, Ildar Barkhatov, Alexander Alyanski, Elena Darskaya, Mariya Vladovskaya, Sergey Bondarenko, Ivan Moiseev, Boris Afanasyev

Pavlov First Saint Petersburg State Medical University, Saint Petersburg, Russian Federation

Background: The overall therapeutic tactics strategy in CML patients has changed drastically after tyrosine kinase inhibitors (TKIs) were introduced. There is, however, a subgroup of advanced disease phase patients or patients with TKIs intolerance/ loss of response, in which the overall prognosis is dismal and allo-HSCT is the only curative option. As a large transplant center we have observed the overall treatment landscape change with new TKIs generations being introduced. This retrospective study summarizes our experiences in pre- and post-TKIs era.

Methods: Our retrospective cohort study includes allo-HSCT recipients with CML treated between 1995 and 2019 (n=114). The diagnosis was based on clinical and laboratory criteria. In all patients either Philadelphia (Ph) chromosome or chimeric BCR-ABL gene were found. Disease stage was determined according to WHO criteria. The chronic phase 1 (CP1) was confirmed in patients with no history of accelerated phase (AC) or blast crisis (BC), otherwise CP≥2 was confirmed. Pre allo-HSCT hematological, cytogenetic or molecular response was evaluated according to ELN criteria. The myeloablative conditioning regimen used consisted of 16 mg/kg of busulfan and 120 mg/kg of cyclophosphamide. However, 96% of patients received reduced intensity conditioning regimen with 180 mg/m2 of fludarabine and 8-14 mg/kg of busulfan or 140 mg/m2 of melphalan.

Results: The number of transplant-eligible CP1 patients decreased dramatically after TKIs introduction. While in 1995-2004 as much as 75% transplant recipients were in CP1 there were only 12% in 2017-2019. In recent years most CP1 patients scheduled for allo-HSCT (93%) have history of TKIs resistance, some also are transplanted after T315I mutation is found or due to treatment intolerance (7%). From 2008 on, there is also a concurrent trend for less CML patients receiving allo-HSCT in AP or BC (50% in 2008 and 21% in 2017-2019). Most of these patients reached CP≥2 on 1st and 2nd generation TKIs. Since 2004-2005 the CP≥2 patients’ proportion is consistently raising reaching as much as 65.6% in 2017-2019. Due to the targeted therapy improvement we are now able to achieve response even in BC patients. Therefore, the proportion of patients with BC history increased from 12% in 2004 to 60% in 2019, 20% of current allo-HSCT recipients having history of several BCs. The latter may point at a failure to refer a patient to allo-HSCT in time. Some recent years are marked by increase of 5-year overall survival (OS) from 25% to 58%, which may be explained by the fact that much less patients are now receiving allo-HSCT in AC or BC. A total of 46 patients in our cohort died, 29% of them (n=13) due to GVHD, 24% (n=11) of infectious complications, 39% (n=18) after disease relapse, 4% (n=2) due to heart attack, 4% (n=2) due to VOD.

Conclusions: The allo-HSCT belongs currently to 3rd or 4th line therapy for CP1 CML patients. It is also still a modality of choice if there is history of AC or BC. New generation TKIs are used to prepare patients for allo-HSCT thus raising significantly the CP≥2 allo-HSCT recipients proportion.

Clinical Trial Registry: NA

Disclosure: Nothing to declare.

P132 Reduced Intensity Allogeneic Stem Cell Transplant with Campath T-cell Depletion for Myelofibrosis in the Era of Jak Inhibitors- A Single Centre Experience

Claire Horgan, Shereef Elmoamly, Alex Kanellopoulos, Richard Lovell, Shankara Paneesha, Bhuvan Kishore, Mary Dillon, Katie O’Collins, Kathy Holder, Emmanouil Nikolousis

University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom

Background: Despite recent advances in understanding the pathogenesis and molecular landscape of myelofibrosis over recent years, the condition continues to pose a number of challenges for the treating clinician. Allogeneic stem cell transplant remains the only potentially curative option, however, the heterogeneity in both clinical course and therapeutic response, as well as patients’ comorbidities, can make it difficult to weigh up the risks and benefits for individual patients. The advent of JAK inhibitors has revolutionized the treatment paradigm over the last decade with preliminary data suggesting positive impact on transplant outcomes. We conducted a retrospective review of patients undergoing a reduced-intensity Alemtuzumab- conditioned allogeneic stem cell transplant for myelofibrosis over a 9-year period, at Birmingham Heartlands Hospital, in order to provide real world data and identify any significant correlation between patient characteristics, JAK-2 inhibitor use, and outcomes.

Methods: We identified 27 patients (16 Male vs 11 Female, 8 sibling donor vs 15 matched-unrelated donor vs 4 mismatched-unrelated donor) who had undergone an allogeneic stem cell transplant for myelofibrosis at Heartlands Hospital between 16th April 2010 and 7th August 2019. 9 patients had received Ruxolitinib prior to allogeneic stem cell transplant. All patients were DIPS score intermediate 2/high. Data was obtained from transplant protocols, discharge letters and clinic letters accessed via the hospital online record system. The information was inputted onto an excel spreadsheet and statistical analysis was carried out using SPSS.

Results: Patients had a median age of 64.6 years and were followed up for a median of 23 months. Median overall survival for the cohort was 65.9%. (see figure 1)

25% patients developed acute graft versus host disease (GVHD) grade 3/4, including 2 patients who died of GVHD, and 14% patients developed chronic GVHD. Only 1 patient died of disease progression post transplant, a 2nd patient progressed but regained remission with donor lymphocyte infusion (DLI) and ruxolitinib. Progression free survival was 62% at 23 months.

37% patients in total received DLI and 1 patient received a stem cell top up for secondary graft failure. 7.4% patients had a prior diagnosis of essential thrombocythemia, and 81% patients had neutrophil engrafted by day +28.

Sibling donors were associated with significantly better survival than matched unrelated donors (p=0.033). There was also a statistically significant improvement in survival in those patients who received DLI (p=0.037).

In our cohort, we did not identify any statistically significant correlation between prior ruxolitinib use and risk of death, progression, or acute and chronic GVHD.

Conclusions: Although patient numbers were small, our results highlight the curative potential of allogeneic stem cell transplantation in myelofibrosis using a reduced intensity approach with Alemtuzumab-based T-cell depletion. This approach is both safe and effective, even in a relatively older population, and the suggestion that post -transplant DLI may confer a survival benefit will need further evaluation in larger multicentre cohorts.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (21)

[Figure 1- overall survival]

Disclosure: Nothing to declare.

P133 Allogenic Stem Cell Transplantation in advanced Systemic Mastocytosis after Cytoreductive Treatment with Cladribine - A Single Center Experience on Two Patients

Christoph Buhl1, Emin Abdullayev1, Johanna Kerschbaum1, Herrad Baurmann1, Andreas Reiter2, Bertram Glaß1

1HELIOS Klinikum Berlin-Buch, Berlin, Germany, 2Universitätsmedizin Mannheim, Mannheim, Germany

Background: Systemic mastocytosis (SM) is characterized by proliferation and accumulation of clonal mast cells in bone marrow, skin and visceral organs. Bone marrow mast cell infiltration, elevated serum tryptase and a KIT D816V mutation (>90% of patients) are diagnostic hallmarks. The various subtypes of this rare haematological neoplasm are characterized by a more or less aggressive course. Targeted therapy against mutant-KIT with midostaurin has been approved, however, complete responses have not yet been reported and durable major response may only occur in 50-60% of patients. Cladribine has demonstrated efficacy in treatment of indolent SM and advanced SM (AdvSM) while allogeneic stem cell transplantation (ASCT) is a treatment option for eligible AdvSM patients with refractory or aggressive clinical course. In a retrospective study, response rates of 70% have been reported at day +100, followed by long term survival in 50-60% of patients.

Methods: We here report on ASCT in two patients (female, 70 years old; male, 50 years old) with aggressive SM and associated myelodysplastic/myeloproliferative neoplasm (ASM-MDS/MPN). The first patient presented with a bone marrow infiltration of 5%, a serum tryptase of 320 µg/l (normal value < 11.4), massive splenomegaly and multiple additional somatic mutations in ASXL1, SETBP1 and CSF3R in addition to KIT D816V. The second patient presented with a bone marrow mast cell infiltration of 80%, a serum tryptase of 540µg/l and only mild splenomegaly. Somatic mutations were identified in KIT D816V, NRAS and TET2. Both patients were resistant to midostaurin but achieved a stable partial remission on one and seven cycles cladribine, respectively. Bone marrow biopsy revealed residual mast cells of < 5% and serum tryptase was decreased to 52µg/l and 102µg/l when conditioning therapy with fludarabine (150mg/m2), treosulfan (36g/m2) and ATG Neovii® (45mg/kgBW) was initiated. Peripheral stem cells from unrelated 10/10 donors were used as stem cell source. While one patient had negligible skin reactions associated to the central line, the second patient presented with high fever and rash one week after transplantation mimicking hyperacute GvHD, which was, however, most likely an associated with mediator release/allergic reaction upon antimycotic treatment with an echinocandin.

Results: Both patients show complete chimerism on day +100, tryptase is normal in the first patient and near normal (35µg/l) in the second patient. The first patient shows mild mucocutaneous chronic GvHD.

Conclusions: Our experience shows feasibility and short-term efficacy of ASCT in ASM-AHN after induction of best possible remission with several cycles of cladribine and treosulfan-based conditioning. Mediator release may remain an important issue during and after transplantation and its differentiation from GvHD may be difficult.

Disclosure: Nothing to declare.

P134 Allogeneic Stem Cell Transplantation for Idiopatic Myelofibrosis: A Single Centre Experience

Matteo Parma1, Elena Elli1, Elisa Diral2, Elisabetta Terruzzi1, Marilena Fedele1, Rossella Renso1, Andrea Aroldi2, Giovanni Zambrotta2, Pietro Pioltelli1, Carlo Gambacorti Passerini1,2

1San Gerardo Hospital, Monza, Italy, 2University of Milano-Bicocca, Monza, Italy

Background: Allogeneic Stem Cell Transplantation (ASCT) is the only curative option for Myelofibrosis (MF). Development of reduced intensity conditioning (RIC) regimens and introduction of Ruxolitinib (Rux) have improved the outcome of ASCT. However, this procedure is still burdened by substantial morbidity and high transplant-related mortality (TRM). Here we report our experience with ASCT in MF setting, in order to evaluate the factors influencing post-transplant outcome, in term of overall survival (OS) and Progression-free survival (PFS).

Methods: In the last 10 years we performed 30 ASCT on 27 MF patients (pts); 3 pts of them received a second ASCT for MF relapse. The median age was 51 (range: 25-68) years. Driver mutations were found in 23 pts and were: JAK2V617F in 16 (59%), MPL in 3(11%) and CALR mutations in 4 (15%) pts; 4 (15%) pts were defined as “triple-negative”. According to Dynamic International Prognostic Scoring System (DIPSS) at transplant, pts were stratified into high, intermediate-2 and intermediate-1 risk in 11 (41%), 12 (44%) and 4 (15%) cases, respectively. Considering the first ASCT, donors were matched related (MRD), matched unrelated (MUD) and haploidentical in 18 (67%), 7 (26%), and 2 (7%) of cases, respectively. Conditioning regimen (CR) was RIC in 11 pts (41%) or myeloablative in 16 pts (59%); all CR were Busulfan and Fludarabine-based, in 48% of cases (n=13) associated with Tiothepa. Conventional GVHD prophylaxis regimens were used according to type of ASCT. Splenectomy or spleen irradiation were performed before ASCT in 2 and 6 pts in pre-Rux era; 16 pts (59%) received Rux before ASCT. Source of stem cells were bone marrow in 15 (56%) or peripheral blood stem cells in 12 (44%) pts. OS and PFS have been evaluated by Kaplan-Meier analysis.

Results: Aafter a median follow-up of 18.5 (range: 0.5 - 175) months from first ASCT, 4/27 pts (15%) died for early TRM, 6 (22%) pts for MF relapse (4) or leukemic evolution (2). 17 (63%) pts were alive, 15 of them with full chimerism and complete remission (one after the second ASCT); 2 pts were alive in MF relapse. Chronic GVHD occurred in 6 (22%) pts.

The probability of OS for the entire cohort at 2 and 5 years was respectively 75% and 60% and the 2 and 5 year PFS was 75% and 55% respectively. In statistical analysis, significant predictive factors of good outcome were: intermediate-1 DIPSS score at transplant, Rux-exposition pre-transplant and development of chronic GVHD. There was no correlation between clinical outcome and type of driver mutations, age at transplant, donor type, CR, source of stem cells.

Conclusions: ASCT in MF is actually a valid therapeutic option for pts eligible to the procedure also in the Rux era. In our experience, earlier stage of MF at time of transplant and Rux exposition before transplant seem to have a favourable impact on the outcome post-ASCT; also a chronic GVHD seems to play a protective role for reducing relapse risk post-ASCT.

Disclosure: Nothing to disclose

P135 A case of Successful Second Haploidentical Bone Marrow Transplantation after Secondary Graft Failure in a Patient with Refractory Chronic Myeloid Leukemia

Nadezhda Shnalieva, Anna Melikhova, Iurii Osipov, Galina Salogub, Vladimir Ivanov, Elza Lomaia

Almazov National Medical Research Centre, Saint-Petersburg, Russian Federation

Background: Allogeneic hematopoietic stem cell transplantation (alloHSCT) is currently considered a mandatory therapy option in patients with refractory to at least two of tyrosine kinase inhibitors (TKI). Haploidentical alloHST are becoming increasingly important in this cohort of patients.

Methods: 33 years old, male. History of CML: blast crisis as a debut; the disease was characterized by primary cytogenetic resistance to imatinib and bozutinib. In the study of BCR-ABL mutations during bozutinib therapy, the T315I mutation was detected. The loss of complete hematological response (CHR) was stated with the preservation of the chronic phase (CP) of CML; cytoreductive therapy with hydroxyurea 3000 mg/day was added to bozutinib. Patient only had one haploidentical donor (mother).

When CHR was achieved, alloHSCT was performed (period from disease debut to alloHSCT is 58 months). Conditioning regimen (CR):fludarabine 150 mg/m2, busulfan 8 mg/ kg; prophylaxis of the graft-versus-host disease (GVHD): high-dose (50 mg/kg DD3,4) cyclophosphamide was administered, tacrolimus and mycophenolate mofetil therapy was initiated at D5. To D+30 the patient had 100% donor chimerism, Ph-chromosome in cytogenetic studies of bone marrow was not determined, but minimal residual disease (MRD) remained-0,210% BCR-ABL p210 (15349 ABL copies). Prophylactic therapy with TKI- dasatinib 50 mg/day was initiated at D+58. From D+62, there was a decrease in donor chimerism: 93.8% (D+62) => 91.5% (D+82) => 91.6% (D+118), MRD by these terms decreased by 1 log. By D+128 immunosuppressive therapy (IST) was withdrawn. From D+148: deepening profundity of persistent cytopenia, decreasing of donor chimerism to 82%. Infusion of donor lymphocytes (DLI) - 1*10^6 CD3+CD45+/kg was performed on D+152. Total bone marrow hypoplasia, decreasing of donor chimerism to 33.5% were detected on D+158. The secondary graft failure was stated.

Results: Second alloHSCT from the same donor was performed within 7 days after the diagnosis of secondary graft failure. CR: fludarabine 150 mg/m2, melphalan 140 mg/m2; prophylaxis of GVHD was the same. On D+29 100% donor chimerism was detected, BCR-ABL p210-0% (11212 ABL copies). By D+63 decreasing of donor chimerism to 93,3% was stated, on D+63 IST was completely withdrawn. On D+78, donor chimerism increased up to 98%. On D+83, due to high risk of secondary graft failure, DLI was performed (5*10^5 CD3+CD45+/kg). On DD+110, +137 full donor chimerism was defined. MRD was not detected during the entire post-transplant period, and therefore prophylactic administration of TKI was not resumed. To date, chronic multilocus GVHD (skin, mucosa, liver) has occurred, which was successfully treated with ruxolitinib and extracorporeal photopheresis.

Conclusions: Allogeneic (haploidentical) HSCT in patients with refractory CML may be a successful alternative to a fully HLA-compatible SCT. Second allogenic (haploidentical) HSCT from the same donor with the change of CR in our patient was effective. As a stimulation of the graft-versus-leukemia (GVL) effect, "earlier” withdrawal of IST and DLI may be successfully performed. “Deep molecular response” in post-transplant period can be achieved without administration of TKI due to satisfactory graft function. Ruxolitinib is actively used in GVHD treatment, and can also stimulate an antitumor response.

Earlier alloHSCT can contribute to reduce incidence of complications.

Disclosure: Nothing to declare.

Conditioning regimens

P136 Combining Clofarabine and Fludarabine with Exposure Targeted Busulfan for Pediatric Leukemia: An Effective, Low Toxic, TBI-free Conditioning Regimen

Anne Birgitta Versluys1,2, Coco de Koning2, Marc Bierings1,2, Stefan Nierkens1,2, Caroline Lindemans1,2, Dorine Bresters1,3, Wouter Kollen1,3, Arjan Lankester3, Jaap Jan Boelens2,4

1Prinses Maxima Centre for Pediatric Oncology, Utrecht, Netherlands, 2University Medical Center Utrecht, Utrecht, Netherlands, 3Leiden University Medical Center, Leiden, Netherlands, 4Memorial Sloan Kettering Cancer Center, New York, NY, United States

Background: The combination of Clofarabine + Fludarabine + Busulfan (CloFluBu) was found to have synergistic anti-leukemic activity against ALL and AML blasts in vitro (Andersson et al: BBMT 2011). As TBI induces significant late effects in childhood ALL, and AML patients have high relapse rates, we hypothesized that CloFluBu may be a potential alternative to TBI in ALL, and could add anti-leukemic activity in AML. Within the “Dutch COG HCT Working Group” we prospectively studied the outcomes of a CloFluBu-conditioning regimen for lymphoblastic and myeloid malignancies.

Methods: Patients from the 2 pediatric HCT programs (LUMC and UMC Utrecht/Princess Máxima Center for Pediatric Oncology) in the Netherlands with a lymphoblastic or myeloid malignancy receiving their first HCT, between August 2011 and April 2019, were included. Over 4 days, Clofarabine 30mg/m2 was given in 1 hour, followed by Fludarabine 10mg/m2 in 1 hour, followed by a 3-hour infusion of once-daily targeted Busulfan (weight-based dosing + therapeutic drug monitoring to a total Bu-exposure of 90mg*h/L). Thymoglobulin was added in unrelated donors (except in AML patients receiving cord blood). GvHD-prophylaxis was according to standard protocols. Minimal Residual Disease (MRD) negative was defined as < 10e-4. Primary endpoints were Overall Survival (OS) and Leukemia Free Survival (LFS). Secondary endpoints were Non Relapse Mortality (NRM), Relapse, acute and chronic Graft-versus-Host Disease (GvHD), and VOD/SOS. Cox Proportional Hazard and fine and gray competing risk models were used for data analysis.

Results: 155 children were included; 66 ALL (38 in CR1, 28 ³ CR2), 69 AML (28 in CR1, 40 in CR2, 1 in active disease) and 20 other malignancies (mostly MDS-EB). Median age was 9.7 (0.5-18.6) years. Most donors were unrelated (119 vs 36 related); 79 Bone Marrow (BM), 66 Cord Blood (CB) and 10 Peripheral Blood Stem Cells. Median follow up was 964 (19-2994) days. Overall the 3-yr estimated OS and LFS was 72 ± 4.5% and 65 ± 5% respectively. Estimated 3-yr LFS for MRD-neg ALL, MRD-pos ALL, AML CR1 and AML CR2 was 74 ± 7%, 40 ± 12%, 64 ± 10%, 65 ± 9% respectively). NRM in whole cohort was 10.3 ± 3.0% (with 25 ± 4.3% for AML CR1 (n=28), and 5.8 ± 2.3% in the rest). Other endpoints: only 2 graft-failures were noted, incidence of aGvHD III-IV at 6 months was 11 ± 3%, extensive chronic GvHD at 3-yr was 5.2 ± 2.2%. Relapse at 3-yr was 25 ± 4.3% (MRD-neg ALL 16.2 ± 3.7%, versus 60 ± 4.9% in MRD-pos ALL, in AML 22.5 ± 4.2%) and no VOD/SOS was noted.

Conclusions: CloFluBu in myeloid- and lymphoblastic malignancies, showed very limited toxicity and encouraging LFS in all groups, in particular for MRD negative ALL. More studies, preferably in randomized controlled clinical trials, are needed to draw firm conclusion with regards to the anti-leukemic effect and late effects.

Clinical Trial Registry: N/A

Disclosure: nothing to disclose

P137 Benda-beam High-dose Therapy Prior to auto-sct is Effective in Resistant/relapsed DLBCL: A Phase II Study

Giuseppe Visani1, Federica Loscocco1, Stefano Guidi2, Potito Scalzulli3, Attilio Olivieri4, Emanuele Angelucci5, Saveria Capria6, Francesca Patriarca7, Barbara Castagnari8, Francesco Angrilli9, Daniele Vallisa10, Gerardo Musuraca11, Andrea Mengarelli12, Piero Galieni13, Francesco Gaudio14, Patrizia Tosi15, Pierluigi Zinzani16, Alberto Bosi2, Nicola Cascavilla3, Barbara Guiducci1, Marco Rocchi17, Alessandro Isidori1

1Hematology and Stem Cell Transplant Center AORMN, Pesaro, Italy, 2Carreggi Hospital, Firenze, Italy, 3IRCCS Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo, Italy, 4Ospedali Riuniti, Ancona, Italy, 5San Martino Hospital, Genova, Italy, 6La Sapienza University, Roma, Italy, 7AOU di Udine, Udine, Italy, 8Santa Maria delle Croci di Ravenna, Ravenna, Italy, 9Spirito Santo Hospital, Pescara, Italy, 10Piacenza Hospital, Piacenza, Italy, 11IRST, Meldola, Italy, 12IRCCS Regina Elena Institution, Roma, Italy, 13Mazzoni Hospital, Ascoli Piceno, Italy, 14AOU Policlinico di Bari, Bari, Italy, 15Infermi Hospital, Rimini, Italy, 16Sant’Orsola Hospital, Bologna, Italy, 17Carlo Bo University, Urbino, Italy

Background: A major drawback affecting clinical trials of high-dose therapy (HDT) followed by autologous stem cell transplant (ASCT) in lymphomas is the high heterogeneity of histological entities. As a consequence, the statistical power is reduced when we focus on a specific histological subset, and data are often not conclusive. We designed a phase II study to evaluate the efficacy of the BeEAM conditioning (bendamustine 200 mg/m2 on days -7,6, cytarabine 400 mg/m2 days -5-4-3-2, etoposide 200 mg/m2 days -5-4-3-2, melphalan 140 mg/m2 day-1) in resistant/relapsed diffuse large B-cell non-Hodgkin lymphoma (DLBCL) patients.

Methods: The study was registered at European Union Drug Regulating Authorities Clinical Trials (EudraCT) N. 2011-001246-14. 64 patients (median age 54.5 years, range 19-70) with resistant/relapsed DLBCL or transformed follicular lymphoma were enrolled. The primary end-point of the study is to evaluate the 1-year complete remission rate.

Results: Briefly, 47/64 patients had advanced stage disease (III-IV); 21 were primary refractory and 43 had relapsed. 33/64 were in II or subsequent CR after salvage therapy, whereas 24 were in PR and 7 in progressive disease. A median number of 5.55x106 CD34+/Kg cells (range 2.07-12.20) collected from peripheral blood was reinfused to patients. All patients engrafted, with a median time to ANC>0.5x109/l of 10 days. Median times to achieve a platelet count >20x109/l and >50x109/l were 13 and 18 days respectively. Twenty-four out of 64 patients presented a FUO (37.5%). One patient died due to an incomplete hematological recovery after transplant and one patient died due to acute liver failure, producing an overall transplant related mortality of 3.1%. Sixty-two patients are evaluable for response: 51/62 (82%) obtained a CR, 4/62 (6%) a PR, whereas 7/62 (11%) did not respond to therapy. The median follow-up after transplant was 34 months (range 1-90).

Conclusions: The stringent inclusion criteria at enrollment allow to precisely evaluate the impact of HDT with Bendamustine followed by ASCT in a highly selected population of patients with DLBCL. The 1 year remission rate was superior to 55%, thus reaching the primary end-point. Accordingly, our data provide the evidence that the Benda-BEAM regimen is safe and has promising high efficacy in resistant-relapsed aggressive diffuse large B cell lymphoma.

Disclosure: Nothing to declare.

P138 Reduced-toxicity Conditioning with Fludarabine, Thiotepa and Melphalan in Allogeneic Hematopoietic Cell Transplantation for Patients with Impaired Lung Function

Jesus Duque-Afonso, Gabriele Ihorst, Miguel Waterhouse, Robert Zeiser, Ralph Wäsch, Hartmut Bertz1, Mehtap Yücel, Thomas Köhler, Joachim Müller-Quernheim, Reinhard Marks, Jürgen Finke

University of Freiburg Medical Center, Freiburg, Germany

Background: The age of patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) has increased during the last decades, mainly due to improved reduced intensity/toxicity conditioning protocols. A reduced-intensity conditioning based on fludarabin, carmustin/BCNU and melphalan (FBM) has been previously developed at our institution. Since we observed detrimental effects in patients with compromised lung function prior allo-HCT and conditioned with FBM, efforts have been made in order to replace BCNU by thiotepa (FTM) to reduce toxicity.

Methods: In this study, we retrospectively analyzed the outcome, Graft-versus-Host (GvHD) incidence, lung function and organ toxicity of patients transplanted at our institution after conditioning with the reduced intensity/toxicity protocols FBM (n=122) and FTM (n=73) between January 1st 2013 and December 31st 2017. Patients were stratified by caring physicians to receive conditioning according to FBM protocol (fludarabine 4x30mg/m², BCNU/carmustine 2x150mg/m² and melphalan by patients >55 years:1x110mg/m² or < 55 years:1x140mg/m²) or FTM (fludarabine 4x30mg/m², thiotepa 2x5 mg/kg and melphalan for patients >55 years:1x110mg/m² or < 55 years:1x140mg/m²). We included in the analysis all patients at first allo-HCT and surviving at least 100 days after allo-HCT. During the observation period, continuously increasing number of patients were treated with FTM. Therefore, patients treated with FBM had a longer median follow-up of 957 (range 104 -2337) vs. 801 days (range 124 -1667) of FTM-treated patients.

The Cox proportional hazards regression model was used to estimate hazard ratios (HR) and confidence intervals (CI) for overall survival and progression-free survival. We applied the Fine and Gray model to compare cumulative incidence rates in the presence of competing risks and presented as subdistribution hazard ratios for relapse incidence, non-relapse mortality, aGvHD and cGvHD incidence. Pearson’s chi-square and Fisher’s exact tests were used to compare categorical variables as appropriate and Student’s T-test to compare continuous variables.

Results: Compared to patients conditioned with FBM, FTM-treated patients were younger and received less frequently GvHD prophylaxis with alemtuzumab. Patients treated with FTM suffered more frequently lymphoid malignancies and received more chemotherapy cycles. As expected, there were more patients with a HCT-CI score ≥ 4 and with impaired lung function allocated in the FTM group, due to the patient selection by caring physicians to the presumably less pulmonary toxic protocol.

Despite a higher comorbidity-index prior allo-HCT, patients conditioned with the FTM protocol show similar overall survival and relapse incidence. Hence, patients with impaired lung function prior allo-HCT, as defined by FEV1< 80% of predicted or DLCOcSB< 80% of predicted, and conditioned with FTM had a 2-year overall survival of 83.0% compared to 71.1% of FBM-treated patients (p=0.11). FTM-treated patients had less pulmonary cause of death compared to patients treated with FBM. In contrast, gastrointestinal complications were more frequently observed in patients conditioned with FTM. No differences were observed in incidence and severity of acute and chronic GvHD. Lung function was reduced in FTM-treated patients prior allo-HCT and 1 year after allo-HCT compared to FBM-treated patients.

Conclusions: In summary, the FTM protocol has reduced toxicity but sufficient anti-neoplastic effect and is suitable for patients with impaired lung function prior allo-HCT.

Disclosure: Nothing to declare.

P139 Allogeneic Stem Cell Transplant with minimal-intensity Conditioning in Patients with Cutaneous T-cell Lymphoma. A Single Centre Retrospective Review

Marianne Gallanagh1, Amy Brown1, Angharad Pryce1, Richard Szydlo2, Stephen Morris3, Renuka Palanicawandar1, Edward Kanfer1

1Imperial Healthcare Trust, London, United Kingdom, 2Imperial College London, London, United Kingdom, 3Guy’s and St. Thomas’ NHS Foundation Trust, London, United Kingdom

Background: Haematopoietic stem cell transplantation (HSCT) in advanced cutaneous T-cell lymphomas (CTCL), of which mycosis fungoides (MF) and Sezary syndrome (SS) are the most common subtypes, is increasingly practiced as a curative therapy. Minimal-intensity conditioning, using a protocol established in Stanford using anti-thymocyte globulin (ATG) and total nodal lymphoid irradiation (TNLI), is an option for CTCL patients, particularly those of older age, and those with chronic colonisation of skin lesions by potentially multi-resistant organisms which would render myeloablative conditioning regimens higher risk. The conditioning protocol comprises initial total skin electron beam therapy (TSEB) (4-8 week course) pre-transplant, followed by TNLI (day -11 to day 0), 10 x in 80cGy fractions of 4 radiation fields (2 anterior and 2 posterior including all major lymphoid areas) and ATG (day -11 through day -7, 1.5mg/kg/day). Ciclosporin was given from day -3 onwards, MMF was given from day +1 onwards. The benefits of this protocol include reduced incidence of acute GvHD and prompt multi-lineage engraftment, with evident graft vs tumour effect.

Methods: This is retrospective case series of 32 CTCL patients who underwent allogeneic transplant for advanced CTCL using the TSEB/ATG/TNLI protocol at a single centre after failure of standard therapy between 2012 and 2019. Of the 32 patients, 3 had SS and 29 of had MF. The number of prior treatments ranged from 3-8. 11 patients had matched sibling allografts, 2 patients had haploidentical sibling allografts and 19 patients had grafts from matched unrelated donors. We used the patients’ transplant protocols and hospital electronic records to retrieve information. We collected data for DFS and OS analyses as well as transplant-related mortality, and the doses and responses to donor lymphocyte infusions (DLI).

Results: We used the Kaplan Meier method to generate survival curves looking at time to two events; disease-free survival (DFS) and overall survival (OS). Of the 32 patients who were transplanted, 14 patients relapsed, of which 4 then died due to the disease progression. 7 patients received at least one DLI post-transplant, either for relapsed disease or falling chimerism, and 4 were successfully salvaged with DLI and chemotherapy/radiotherapy. An additional 5 patients died due to sepsis/GvHD. 13 patients remain in remission. The Kaplan Meier estimates of 5-year OS and 5-year DFS in this study were 63% and 45%, respectively.

Conclusions: Use of this minimally intensive protocol resulted in a predicted OS of 2/3 of patients at 5 years with approximately half of the patients being disease free, suggesting promising long-term outcomes in a disease with otherwise poor overall survival. This study has shown successful engraftment can be achieved with this minimally-invasive protocol and suggests reducing the risk of non-relapse related mortality can be achieved without increasing risk of relapse or progression. For those who relapse DLI may be of benefit and further study of its use in this setting is recommended.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (22)

[Kaplan Meier Survival Curves]

Disclosure: Nothing to declare.

P140 Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Acute Lymphoblastic Leukemia and Karnofsky Performance Status Score Equal or Lower Than 80%. A Study from the ALWP-EBMT

Francesco Saraceni1, Myriam Labopin2, Riitta Niittyvuopio3, Gerard Socié4, Nicolaus Kröger5, Edouard Forcade6, Paul Browne7, Péter Reményi8, Jan Cornelissen9, Stephen Robinson10, Ibrahim Yakoub-Agha11, Thierry Lamy12, Eolia Brissot2, Bipin Savani13, Arnon Nagler14, Mohamad Mohty2

1Ancona University Hospital, Ancona, Italy, 2Saint Antoine Hospital, Paris, France, 3HUCH Comprehensive Cancer Center, Stem Cell Transplantation Unit, Helsinki, Finland, Helsinki, Finland, 4Hopital St. Louis, Paris, France, 5University Hospital Eppendorf, Hamburg, Germany, Hamburg, Germany, 6CHU Bordeaux, Hôpital Haut-leveque, Bordeaux, France, 7St. James`s Hospital, Dublin, Ireland, 8Dél-pesti Centrumkórház - OrszágosHematológiaiésInfektológiaiIntézet, Budapest, Hungary, 9Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands, Rotterdam, Netherlands, 10Bristol Royal Hospital for Children, Bristol, United Kingdom, 11CHU de Lille, LIRIC, INSERM U995, Université de Lille, Lille, France, 12Centre Hospitalier Universitaire de Rennes, Rennes, France, 13Vanderbilt University Medical Center, Nashville, TN, United States, 14Chaim Sheba Medical Center, Tel-Hashomer, Israel

Background: We report here the results of a retrospective study designed to evaluate outcome of ALL patients undergoing allo-HCT with KPS score ≤80%.

Methods: The analysis included ALL patients aged ≥18 years, undergoing allo-HCT in first remission between 2000 and 2018, with a KPS score of 50% to 80% at the time of transplant. Patients who received manipulated grafts or had incomplete data about cytogenetics were excluded. Conditioning intensity was defined according to EBMT definitions (Aoudjhane M. et al, Leukemia 2005; 19: pp. 2304-2312).

Results: A total of 1,010 patients were identified. Median age at transplant was 43 years (18-76 years). Median year of transplant was 2011. The KPS score was =80% in 83% of the patients and < 80% in 17% of the patients. Diagnosis was Philadelphia chromosome (Ph) negative B-ALL, Ph positive B-ALL or T-ALL in 34%, 44% and 22% of the patients, respectively. Donor type was MSD or 10/10 UD in 60% and 40% of the patients, respectively. Conditioning was myeloablative (MAC) or reduced-intensity (RIC) in 78% and 22% of the patients, respectively, and it was TBI-based in 79% of the patients. Stem cell source was PBSC in 76% and BM in 24% of the patients, respectively. Anti-thymocyte globulin (ATG) was administered to 21% of the patients receiving MSD and 68% of the patients receiving 10/10 UD as donor type. Cumulative incidence of grade II-IV and III-IV aGVHD was 32% and 9%, respectively. The 2-year cumulative incidence of chronic GVHD (cGvHD) and severe cGVHD was 43% and 18%, respectively. Non relapse mortality (NRM) and relapse incidence (RI) at 2 years were 18% and 28%, respectively. At 2 years, leukemia-free survival (LFS), overall survival (OS) and GVHD-free, relapse-free survival (GRFS) rates were 54%, 64% and 41%, respectively.

On multivariate analysis, transplant from 10/10 UD was associated with higher incidence of aGVHD (HR 1.8, p< 0.0001) and higher risk of NRM (HR 1.7, p< 0.01) as compared to MSD. RIC conditioning was associated with higher risk of relapse (HR 1.2, p=0.02), lower LFS (HR 1.3, p=0.03) and lower GRFS (HR 1.3 p=0.02) as compared to MAC. NRM was not significantly different between MAC and RIC. Factors independently associated with improved OS were younger age at transplant, female sex, more recent year of transplant and Ph+ B ALL phenotype. Administration of ATG was associated with reduced risk of developing grade II-IV aGVHD (HR 0.6, p< 0.001), cGVHD (HR 0.5, p< 10-4) and severe cGVHD (HR 0.4, p< 10-4).

Conclusions: In conclusion, allo-HCT is feasible in patients with acute lymphoblastic leukemia in first remission and KPS score ≤80%, with acceptable NRM and survival rates. Transplant from a sibling donor was associated with reduced risk of NRM and aGVHD as compared to matched unrelated donor. Interestingly, despite the poor KPS score of the patients included in the analysis, a MAC protocol was associated with similar NRM, lower relapse and better LFS and GRFS as compared to RIC in the selected population. Finally, administration of ATG was associated with reduced acute and chronic GVHD rates.

Disclosure: Nothing to declare.

P141 A Prospective Cohort Study Comparing long-term Outcomes with and without Palifermin in Patients Receiving Hematopoietic Cell Transplantation for Hematologic Malignancies

Wael Saber1, Patricia Steinert1, Mei-Jie Zhang1,2, Min Chen1, Andrea Pope1, Armand Keating3, John Wingard4, Karen Ballen5, Patrick Stiff6, Miguel-Angel Perales7, Stephen Forman8, Richard Champlin9, Amelia Langston10, Torbjörn Kullenberg11, Mattias Rudebeck11, Mary Horowitz1

1CIBMTR (Center for International Blood and Marrow Transplant Research), Medical College of Wisconsin, Milwaukee, WI, United States, 2Medical College of Wisconsin, Milwaukee, WI, United States, 3Princess Margaret Cancer Center, Toronto, Canada, 4University of Florida, Gainesville, FL, United States, 5University of Virginia Health System, Charlottesville, VA, United States, 6Loyola University Medical Center, Maywood, IL, United States, 7Memorial Sloan Kettering Cancer Center, New York, NY, United States, 8City of Hope, Duarte, CA, United States, 9University of Texas MD Anderson Cancer Center, Houston, TX, United States, 10Winship Cancer Institute of Emory University, Atlanta, GA, United States, 11Swedish Orphan Biovitrum (Sobi), Stockholm, Sweden

Background: Incidence of debilitating oral mucositis (OM) can be as high as 99% after myeloablative conditioning regimens preparing patients with hematologic malignancies for hematopoietic cell transplant (HCT). Palifermin is a recombinant human keratinocyte growth factor that stimulates proliferation and differentiation of epithelial cells. In randomized controlled trials, palifermin reduced incidence and duration of severe OM in patients with hematologic malignancies receiving myelotoxic therapy in the setting of autologous hematopoietic cell support. Long-term safety of palifermin or the potential risk of stimulation of new malignancies (NM), however, has not been well established.

Methods: In this long-term, prospective, matched cohort study, patients who received palifermin and underwent autologous or allogeneic HCT for hematologic malignancies from 2006-2013 were 1:1 matched to patients who did not receive palifermin. Subjects were matched on age, HCT type, donor type, HCT date, disease type, disease status, region, and whether TBI was included in the conditioning regimen. Primary outcomes were overall survival (OS), relapse, and NM.

We adjusted for imbalances with a propensity score, modeled by logistic regression. The following covariates were used to identify factors associated with treatment assignment: age, race, disease, disease status, time from diagnosis to HCT, prior radiotherapy, type of HCT, growth factors use, graft source, donor age, donor-recipient sex and cytomegalovirus (CMV) serostatus match, conditioning regimen, graft-vs-host disease (GVHD) prophylaxis, year of HCT, and region. Equal propensity scores in both groups predicted they were equally likely to be treated with palifermin. Relative risks were estimated using Cox proportional hazards regression analysis, stratifying on the matched pair and considering the propensity score as a continuous covariate.The 46th Annual Meeting of the European Society for Blood and Marrow Transplantation: Physicians Poster Session (P001-P706) (23)

[Figure 1 overall survival; Figure2 New Malignancy]

Results: The analysis population consisted of 2191 matched pairs. The median follow-up was 8 years (range, 1-12.5 y), with excellent completeness of data across both arms (93% at 8 y). Overall, the median age was 51 y (range, < 1-80 y). HCT for acute leukemia was the most common indication (40%), followed by plasma cell disorder (28%), and non-Hodgkin lymphoma (13%). TBI was used in 41% of conditioning regimens. Fifty percent of the matched pairs underwent allogeneic HCT, and the two most common donor types were identical siblings (37%) and well-matched unrelated donors (35%). Among allogeneic HCT recipients, the majority (88.5%) received myeloablative regimens. In multivariate analyses, the relative risks of OS, relapse, and NM were not statistically significantly different between those who received palifermin and those who did not (relative risk [RR] for OS 1.01 (95% confidence intervals [CI] 0.91-1.12); RR for relapse 1.06 (95% CI 0.94-1.18); RR for NM 0.89 (95% CI 0.67-1.18)) (Figures 1, 2). The potential interactions between receiving palifermin and propensity score were tested, and no interactions were detected.

Conclusions: Long-term safety of palifermin was confirmed with no increased risk of overall mortality, relapse or NM.

Clinical Trial Registry: Not applicable

Disclosure: Swedish Orphan Biovitrum (Sobi) contracted with CIBMTR for services associated with fulfillment of the LTFU study. CIBMTR aligns all activities through the lens of its research mission and utilizes funding sources only to expand research infrastructure and to facilitate a broad research portfolio. It contractually maintains independent review and publication rights and, as such, does not consider the services provided to be a conflict of interest.

Kullenberg and Rudebeck are employees and shareholders of Sobi.

Dr. Perales reports honoraria from Abbvie, Bellicum, Celgene, Bristol-Myers Squibb, Incyte, Merck, Novartis, Nektar Therapeutics, Omeros, and Takeda. He serves on DSMBs for Cidara Therapeutics, Servier and Medigene, and the scientific advisory boards of MolMed and NexImmune. He has received research support for clinical trials from Incyte, Kite/Gilead and Miltenyi Biotec. He serves in a volunteer capacity as a member of the Board of Directors of American Society for Transplantation and Cellular Therapy (ASTCT) and Be The Match (National Marrow Donor Program, NMDP), as well as on the CIBMTR Cellular Immunotherapy Data Resource (CIDR) Committee.

P142 Pharmacokinetics of Melphalan in Lymphoma Patients undergoing Beam and Autologous Hematopoietic Stem Cell Transplant

Parastoo Dahi1,2, Andew Lin1, Jessica Flynn1, Christian Uruburo1, Ian Mcgeary1, Ryan Schofield1, Valkal Bhatt1, Lauren Derespiris1, Bradley Figgins1, Meagan Griffin1, Carmen Lau1, Anthony Proli1, Dean Carlow1, Christina Cho1,2, Oscar Lahoud1,2, Miguel Perales1,2, Craig Sauter1,2, Michael Scordo1,2, Gunjan Shah1,2

1Memorial Sloan Kettering Cancer Center, New York, NY, United States, 2Weill Cornell Medical College, Cornell University, New York, NY, United States

Background: High dose chemotherapy with BEAM (Carmustine, etoposide, cytarabine and melphalan) is a standard regimen for autologous hematopoietic cell transplantation (AHCT) in lymphoma patients. Multiple myeloma studies have shown that dosing melphalan as a fixed dose based on body surface area leads to inter-patient differences with a 5-fold variability in area under the curve (AUC), with higher AUCs associated with improved outcomes but increased toxicity. In this study, the pharmacokinetics (PK) of Evomela® (propylene glycol free melphalan, PGF-MEL) in BEAM, and its associations with outcome and toxicity were evaluated.

Methods: On D-1 prior to AHCT, 140 mg/m2 of PGF-MEL was given over 30 minutes and serum sample were drawn serially at 5, 15, 30, 40, 75, and 150 minutes after the dose. AUC PK modeling was done with Cetara Phoenix WinNonlin, Princeton, NJ. Toxicity collection is ongoing using CTCAE v4 through D+100 after AHCT.

Results: Eighty-seven patients that received BEAM conditioning between 08/2016 and 09/2019 had melphalan PK analysis. The median age was 51 (range, 19-74), 62% were male, and 53% had aggressive B-cell lymphoma. The median PK parameters were as follows: AUC 8.1 mg*h/L (range, 3.8-18.8); clearance 31.8 L/h (range 16.4-79.1); volume of distribution 33.2 L (range, 19.7-70.1); and half-life of elimination 0.7 hours (range, 0.5-1.7). The median dose of melphalan given was similar between patients ≤ median AUC and those above (260 mg [range, 200-340 mg) and 270 mg [range, 210-340 mg], respectively.) With a median follow up of 8.94 months (range 0.72-32.91) in survivors, univariate analysis showed no difference in 1-year overall survival (OS) (95.5% [84-100%] vs. 87.4% [76.5-100%], p=0.2) or progression-free survival (PFS) (78.4% [63.6-96.6%] vs. 78% [63.7-95.5%], p>0.99) when evaluating patients ≤ or above median melphalan AUC, respectively. Patients with a melphalan AUC ≤ the median had an average length of stay of 19 days (range, 5-27) vs. 21 days (range, 7-38) for those above the median exposure (OR 1.19 [1.05-1.38], p = 0.004). Toxicity data collection is ongoing.

Conclusions: Melphalan exposure ≤ 8.1 mg*h/L resulted in a shorter length of hospitalization likely driven by less toxicities, that will be reported upon completion of toxicity collection. Despite early results showing no difference in OS and PFS, the 5-fold variability seen with PGF-MEL AUC suggests that a sweet spot to optimize outcomes and minimize toxicities is needed.7

Characteristic≤ Median AUC (N = 45)> Median AUC (N = 42)OR (95% CI)P-value
Age - yr (median, range)40 (19-74)62 (30-74)1.09 (1.05-1.14)< 0.001
Sex - N (%) Male28 (62)26 (62)1.02 (0.43-2.45)> 0.9
Disease- N (%)< 0.001
B-cell lymphoma (aggressive)15 (33)31 (74)-
B-cell lymphoma (indolent)3 (7)3 (7)0.73 (0.11-5.95)
Hodgkin lymphoma16 (36)3 (7)3 (7)
T-cell lymphoma11 (24)5 (12)0.22 (0.06-0.72)
Length of stay - days (median, range)19 (5-27)21 (7-38)1.19 (1.05-1.38)0.004

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[Table 1. Baseline Characteristics]

Clinical Trial Registry: n/a

Disclosure: Valkal Bhatt (Incyte)

Miguel Perales (MolMed, NexImmune, Abbvie, Bellicum, Bristol-Myers Squibb, Incyte, Nektar Therapeutics, Novartis, Omeros, Takeda, Kite, Merck, Servier, Medigene)

Craig S. Sauter (Juno Therapuetics, Sanofi-Genzyme, Celgene, Spectrum Pharmaceuticals, Novartis, Genmab, Precision Biosciences, Kite, a Gilead Company, Gamida Cell, Pfizer, GSK)

Gunjan L. Shah (Janssen, Amgen)

P143 Comparison of Total Body Irradiation- vs chemotherapy-based Conditionings for Early Complications of Allogeneic Hematopoietic Stem Cell Transplantation in Children with All

Koray Yalcin1, Berrin Pehlivan2, Gulsun Karasu1, Vedat Uygun3, Seda Ozturkmen3, Hayriye Daloglu3, Suna Celen1, Dayanat Pashayev1, Elif Gulsah Bas2, Canan Kabakci2, Fugen Pekun1, Volkan Hazar1, Akif Yesilipek1

1MedicalPark Göztepe Hospital, İstanbul, Turkey, 2Bahcesehir University, İstanbul, Turkey, 3MedicalPark Antalya Hospital, Antalya, Turkey

Background: Pediatric patients with acute lymphoid leukemia (ALL) mainly receive myeloablative conditioning regimens based on total body irradiation (TBI) or chemotherapy (CHT) including busulfan before allogeneic hematopoietic cell transplantation (allo-HSCT). Due to severe long term complications of TBI, CHT-based conditioning has been preferred in many centers for pediatric patients. But there is lack of data about the early complications of allo-HSCT comparing TBI vs CHT.

Methods: To compare early complications of TBI and CHT consisting of busulfan, fludarabine and thiotepa conditioning regimens, we performed a retrospective analysis of single center registry data collected between 1st of January, 2015 and 30th of June, 2019 to assess the outcomes of patients receiving these regimens before an allo-HSCT. Variables associated with early complications of allo-HSCT (only in the first 100 days after transplant) and hence included into the analysis were: engraftment time, engraftment syndrome, acute graft versus host disease (aGVHD) grade 2-4, veno-occlusive disease (VOD), capillary leakage syndrome (CLS), thrombotic microangiopathy (TMA), cytomegalovirus (CMV) reactivation, bloodstream infection (BSI), hemorrhagic cystitis and posterior reversible encephalopathy syndrome (PRES).

Results: The characteristics of 72 patients was revealed in Table 1. These two conditioning regimens (CHT, n: 50; TBI, n: 22) were compared in pediatric ALL patients aged 18 years or younger at the time of transplantation in complete morphological remission (CR) (CR1, n: 40/CR2, n: 30/>CR2, n: 2). The incidences of aGVHD grade 2-4, VOD, CLS, TMA, BSI, hemorrhagic cystitis and PRES before day 100 were similar for both conditioning regimens; however, patients received TBI-based conditioning had significantly longer neutrophil engraftment time (17.5 vs 13 days, p: 0.001) and tended to have more engraftment syndrome (45.5% for TBI vs 24.0% for CHT, p: 0.069). Multivariate analysis showed that TBI-based conditioning was associated with a longer neutrophil engraftment time (HR: 1.20, p: 0.006), more CMV reactivation (HR: 3.65, p: 0.038) and more engraftment syndrome (HR: 3.18, p: 0.078). At the time of last follow-up, 59 patients were alive. Four patients died of disease progression and infection (n: 4) was the most common cause of non-relapse mortality (NRM). With a median follow-up of 25 months (2-45 months), 3 year-overall survival (OS) and -event-free survival (EFS) were 79.1% (95% CI 68.9-89.4). There was no survival advantage between two conditioning regimens [84.2% (95% CI 67.7-100.0) for TBI and 77.0% (95% CI 64.2-89.7) for CHT, p: 0.538]. Cumulative incidence of relapse (CIR) and NRM were 11.9% (95% CI 6.2-22.4) and 14.0% (95% CI 7.6-26.0), respectively, for all patients. Both groups showed a similar CIR and NRM [CIR, 5.0% (95% CI 0.7-37.1) for TBI and 6.6% (95% CI 2.2-19.7) for CHT, p: 0.844; NRM, 10.2% (95% CI 2.7-38.3) and 15.7% (95% I 7.9-31.5), respectively, p: 0.588].

Conclusions: Although this retrospective registry-based analysis has several limitations, both conditioning regimens showed a similar early complications profile. Conditioning by TBI demonstrated longer neutrophil engrafment time and more CMV reactivation in comparison to CHT and also there is a tendency for engraftment syndrome with TBI based conditioning. Comparison of these conditioning regimens warrant further evaluation in a prospective manner.

Disclosure: Nothing to declare.

P144 Differential Alemtuzumab Dosages in T-cell Deplete Allogeneic Haematopoietic Stem Cell Transplants for Myeloid Malignancies

Varun Mehra1, Daniele Avenoso1, Ximena C Castellano1, Adrian Choy1, Stefani Widya2, Mili Shah1, Shafqat Inam1, Shreyans Gandhi1, Austin Kulasekararaj1, Pramila Krishnamurthy1, Francesco Dazzi1, Hugues de Lavallade1, Victoria Potter1, Ghulam J Mufti1, Tony Pagliuca1

1King’s College Hospital, London, United Kingdom, 2King’s College London, London, United Kingdom

Background: Alemtuzumab is a monoclonal anti-CD52 antibody, a pan-lymphodepleting immunosuppressive agent in common use as part of conditioning for allogeneic stem cell transplantation (Allo-HSCT) in United Kingdom and many other centres across the globe, with benefits related to reduced graft versus Host disease (GVHD) and lower non-relapse mortality (NRM). However, evidence for effective dose schedule in Allo-HSCT remains debatable with some concerns related to delayed immune reconstitution, increased relapses with higher doses; but increased risk of acute and chronic GVHD with lower doses.

Methods: We retrospectively evaluated 391 patients undergoing Allo-HSCTs for myeloid malignancies(AML/MDS/MPNs) during 12-year period (Jan 2008 to April 2019) at Kings College Hospital, London. Two dosage schedules of Alemtuzumab based T-cell deplete conditioning with FluBu and Bu-Cy regimens using standard 100mg dose (n-158; 40.4%) were compared to those (n-233; 59.6%) receiving a lower < 100mg dose, with respect to HSCT outcomes. Close monitoring for infections, GVHD, chimerism (included fractionated lymphoid/myeloid) and disease assessments post HSCT were undertaken as per institutional policy.

Results: Baseline characteristics were broadly similar between the 2 groups in terms of conditioning intensity, patient age, underlying disease, disease risk index and donor HLA matching. Median follow up of survivors was 38 months (range 01-136months) with significantly longer follow up available for 100mg group (median 102 months vs 28 months;p< 0.001). Standard Alemtuzumab dose (100mg) was associated with a significant improvement in composite GRFS (54% vs 24% at 60 months; p< 0.001; Fig 1a) and significantly lower incidence of both grade 3-4 acute (18% vs 42% at D100; p-< 0.003; Fig 1b) and chronic GVHD (all grades)(19% vs 42% at 12 months; p< 0.001; Fig 1c) compared to < 100mg dose. No differences in OS (45% vs 45% at 60 months; p-0.55; Fig 1d), NRM (28% vs 23% at 60 months; p-0.32; Fig 1e) and relapse incidences (29% vs 30% at 60 months; p-0.75; Fig 1f) were observed along with no impact on rates of CMV, Adenoviraemia or invasive fungal disease(IFD) between the 2 cohorts, except lower EBV viraemia incidence was noted in 100mg dose group(49% vs 66%; p< 0.001).

Multivariate adjusted cox analysis (MVA) confirmed older age>60 years, mismatched unrelated donor, absence of chronic GVHD, disease relapse, ITU admission event, CMV reactivation and absence of any EBV reactivation post HSCT as significant predictive factors for poor OS, but this not affected by different Alemtuzumab doses, disease risk index or type of disease. Similarly NRM was not affected by differential alemtuzumab doses, while GRFS was positively influenced by standard 100mg dose on MVA

Conclusions: Despite concerns of relapses and delayed immune reconstitution, this report on a homogenous cohort of allo-HSCTs in myeloid malignancies confirms the contrary with no impact on OS, NRM or relapses and no significant increase in opportunistic infections with 100mg dose. With improved supportive care, effective infection management and pre-emptive cellular therapy approaches available in current era, standard dose (100mg) of alemtuzumab can be considered safe and effective in both RIC and myeloablative allo-HSCTs for myeloid malignancies, with significantly lower GVHD related morbidity and overall better GFRS.

Disclosure: No disclosures or conflict of interest to declare.

P145 Novel Reduced Intensity Conditioning (RIC) Approach to Allogeneic Hematopoietic Cell Transplantation (HCT) in Patients with Benign and Malignant Disorders of T Cell Proliferation or Dysregulation

Dimana Dimitrova1, Gulbu Uzel2, Luigi D. Notarangelo2, Amanda K. Ombrello3, Deborah Stone3, Mark Parta4, Ellen Carroll1, Jennifer Wilder4, Stephanie N. Hicks1, Jennifer L. Sadler1, Daniel H. Fowler1, Ronald E. Gress1, Christopher G. Kanakry1, Jennifer A. Kanakry1

1National Institutes of Health, National Cancer Institute, Bethesda, MD, United States, 2National Institutes of Health, National Institute of Allergy and Infectious Disease, Bethesda, MD, United States, 3National Institutes of Health, National Human Genome Research Institute, Bethesda, MD, United States, 4Frederick National Laboratory for Cancer Research sponsored by the National Cancer Institute, Frederick, MD, United States

Background: HCT has been used for decades as a definitive therapy in both primary immunodeficiency (PID) and hematological malignancy. A subset of these patients have a dysregulated T cell compartment either due to underlying PID or peripheral T cell lymphoma (PTCL) and are at particularly high risk of graft failure and/or relapse but may also enter HCT with significant comorbidities necessitating a low toxicity approach.

Methods: Twelve patients with PID (n=7) or PTCL (n=5; relapsed, n=3 and primary refractory, n=2), median age 22 years (range 7-64) received a serotherapy-based, radiation-free RIC platform designed with the goals of enhancing host T cell depletion pre-HCT to reduce graft failure risk and provide disease control, while also optimizing immune reconstitution, minimizing toxicities and complications such as graft-versus-host disease (GVHD), and permitting use of alternative donors via a posttransplantation cyclophosphamide-based approach. This was a high-risk cohort with median HCT comorbidity index score of 3 (range 0-7), and active disease in 2 PTCL patients at time of HCT. Alternative donors were commonly used: 5 patients received mismatched grafts (4 haploidentical, 1 mismatched unrelated) and 5 matched unrelated grafts. Patient and donor characteristics are detailed in Figure 1b.

Results: Neutrophil recovery occurred at median day +16 (range 13-25). With median follow up of 6 months (range 2-14), graft-failure-free survival was estimated at 81% at 6 months, with no deaths. There were 2 graft failures (1 primary, in context of rising donor-specific HLA antibodies despite desensitization, and 1 secondary), both now with full donor chimerism after retransplantation. GVHD rates have been low, with grade 1 skin only acute GVHD, not requiring systemic therapy (n=1), grade 2 steroid-responsive acute GVHD of the skin and gut (n=1), and mild chronic GVHD (n=1). Bacterial infectious complications included sepsis/pneumonia (n=2), bacteremia (n=2), and furunculosis (n=1). While BK virus-associated hemorrhagic cystitis occurred at high rates (58%), severe viral complications were infrequent. CMV reactivation occurred in 29% of known at-risk patients (n=2 of 7), with no CMV disease. RSV, asymptomatic adenoviruria, and anemia due to parvovirus B19 occurred in 1 patient each, none requiring inpatient management. At last follow up, some degree of phenotype reversal is evident in all PID patients, and all PTCL patients are either in confirmed complete remission (n=2) or show no clinical signs of disease (n=3).

Conclusions: Based on promising early outcomes, this novel platform offers a safe and effective HCT approach to diseases with historically poor survival or high risk of graft failure, while enabling use of alternative donors. Longer term follow up is needed to better characterize phenotype reversal in PID patients, incidence of relapse in PTCL patients, graft durability, immune reconstitution and late toxicities of the platform.

Clinical Trial Registry: NCT03663933

NCT03922724

Disclosure: None

P146 Profound Lymphopenia at the time of anti-thymocyte Globulin Administration is not Predictive of Survivals after allo-transplantation

Maxime Jullien1, Thierry Guillaume1, Pierre Peterlin1, Alice Garnier1, Amandine Le Bourgeois1, Camille Debord1, Beatrice Mahe1, Viviane Dubruille1, Soraya Wuilleme1, Nicolas Blin1, Cyrille Touzeau1, Thomas Gastinne1, Benoit Tessoulin1, Yannick Le Bris1, Marion Eveillard1, Alix Duquesne2, Philippe Moreau1, Steven Le Gouill1, Marie C Bene1, Patrice Chevallier1

1Nantes University Hospital, Nantes, France, 2EFS, Nantes, France

Background: Prophylactic T cell depletion via anti-thymocyte globulin (ATG) during ASCT conditioning is a standard of care for GVHD prophylaxis, although the optimal dosing strategy is still unknown. Recent studies have reported that absolute lymphocyte counts at the time of ATG administration (ALC/ATG) may predict survivals in ASCT with unrelated donors, suggesting that the dose (especially at the cut-off of < 0.1x109/L) and timing of ATG administration must be taken into account (Soiffer et al, JCO 2017; Kennedy et al, BBMT 2018).

Methods: To examine this issue, the outcome of ASCT was evaluated in all consecutive patients transplanted between 2009 and 2019 for a hematologic malignancy in our department. Conditioning regimen were purine analogue/busulfan/ATG-based. The reduced-intensity conditioning (RIC) regimen consisted of fludarabine 30mg/m²/day (d) from d-6 to d-2, busulfan 3,4 mg/kg/d from d-4 to d-3 and ATG (Thymoglobuline, Sanofi, Lyon, France) 2,5 mg/kg/d, d-2 and d-1 (FB2A2) or the same but with clofarabine 30mg/m²/d in replacement of fludarabine with 1 or 2 d of ATG (CloB2A2/CloB2A1). Reduced-toxicity myeloablative conditioning regimens (RTMAC) consisted of the same as FB2A2 but with 3 or 4 d of busulfan instead of 2 (FB3A2/FB4A2). Peripheral blood stem cells were used as source of graft from matched or 9/10 mismatched unrelated donors or siblings. We exhaustively looked at patients for whom a blood differential was available in order to evaluate the impact of lymphocyte counts at the time of ATG administration (ALC/ATG) in terms of overall, disease-free and GVHD-free/relapse-free survival.

Results: Of 395 eligible patients, 116 had a documented differential on the day of ATG administration. The median follow-up for alive patients was 49 months. RIC was administered in 80 (69%) of the patients as follows: 39 FB2A2, 12 CLOB2A2 and 29 CLOB2A1. The 36 other patients received RT-MAC: FB3A2 for 27 and FB4A2 for 9 respectively. Four-year OS, DFS and GRFS were 56.2% (47-66), 40.9% (32-51) and 34.5% (26-45), respectively for the whole cohort.

ROC curve analysis failed to identify a cut-off allowing to predict better survivals according to ALC/ATG. The median ALC/ATG was 0.070x109/L (range: 0-2.300). No difference in terms of survivals was observed when considering patients under this threshold vs others (Fig A). The same was true when considering 0.100x109/L as ALC/ATG cut-off. Regarding MAC, the median ALC/ATG was 0.100x109/L with no difference in survivals between patients under or above this value. The same was true for RIC with ALC/ATG cut-offs below the median (0.055x109/L) or below 0.100 x109/L. Interestingly, considering patients with ALC/ATG below 0.100 x109/L within the RIC setting, survivals were similar between patients who received 1d (n=25) or 2d (n=29) of ATG (Fig B).

Conclusions: This study indicates that ATG can be administered to ASCT recipients whatever the conditioning regimen and the lymphocyte count.

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[Survivals according to (A) ALC/ATG (B) number of ATG administration in lymphopenic patients]

Clinical Trial Registry: Non applicable

Disclosure: Nothing to declare.

P147 Lipid Core Nanoparticles as Vehicle for Etoposide in the Conditioning Regimen of Marrow Transplantation in Acute Myeloid Leukemia not Responding to Induction Therapy: Pilot Study

Sandra Serson Rohr1,2, Raul Cavalcante Maranhao3,4, Thauany Martins Tavoni3, Aleksandra Tiemi Morikawa3, Debora Fernandes Deus3, Jose Salvador Rodrigues Oliveira1,2

1Unifesp, Sao Paulo, Brazil, 2Santa Marcelina, Sao Paulo, Brazil, 3INCOR, Sao Paulo, Brazil, 4USP, Sao Paulo, Brazil

Background: Myeloablative conditioning regimens for HSCT elicits high toxicity

Maranhao (1994, 2003) have already showed that lipid core nanoparticles (LDE), as carrier of anti-cancer drugs reduces drug toxicity. We tested LDE-etoposide in the myeloablative conditioning regimen of HSCT of AML patients not responding to induction therapy.

Methods: A prospective pilot study with 15 patients from 2 academic hospitals in São Paulo, Brazil

Inclusion criteria: primary AML not responding to the induction therapy, 18 - 70yr, HLA-matched related or unrelated donor, ECOG ≤ 2, Karnofsky ≥ 80, and comorbidity score ≤ 2. Exclusion criteria: haploidentical donor or umbilical cord blood.

Conditioning regimen: LDE-etoposide from 20mg/kg/BW until 60mg/kg/BW on D-7 and D- 6 and TBI 1200cGy on D-3, D-2 and D-1. D0: day of stem cells infusion. For unrelated donors, thymoglobulin was added. Graft-vs-host disease (GVHD) prophylaxis: cyclosporine and methotrexate.

Results: 15 AML patients (8 males, 7 females), aged 22-66 yrs (median 47 yrs), 10 x 10 HLA-matched stem cells (9 related, 6 unrelated donors) were enrolled. Peripheral stem cell donors were mobilized with GCSF. CD34+ average infused cells were 7.6±1.6 x 106 /kg/BW. Two patients received peripheral and marrow stem cells: CD34+ (9.0±1.0 x 106 cells/kg/BW) and TNC (3.5±0.5 x 108 cells/kg/ BW). Neutrophil engraftment occurred on day 20 ± 5 and platelet 16 ± 4. All patients engrafted. There were no episodes of hypotension, anaphylaxis, or other adverse effects during LDE-etoposide infusion. There was no grade 4 or higher toxicities. Grade 3 toxicity: mucositis (6 patients), diarrhea (3) and elevation of total bilirubin (1), all before D+30. SOS was observed in 1 patient based on the Seattle criteria, which did not fulfill the Baltimore criteria.

Acute GVHD: skin grade 1 in 4 patients and grade 2 in 1. One patient had skin and GI grade 1 aGVHD. The rate of systemic aGVHD was 33,7% (26.7% grade 1, 6.7% grade 2). Chronic GVHD: 8 patients (57,1%): 4 moderate global cGVHD (28.6%) and 4 severe global cGVHD (28.6%). No fatal GVHD events occurred.

CMV reactivation: 5 patients before D+100 and 1 patient after D+100. Bacterial infection: 7 patients before D+ 100 (3 by multiresistant bacteria) and in 7 patients after D+100 (2 by multiresistant bacteria). One patient had disruption of the pulmonary aspergilloma on D+41 after engraftment and one reactivated Aspergilosis sp infection after D+60.

Five patients died, one before D+100 (aspegilloma disruption), 3 patients of refractory relapse on D+174; D+207, and D+285; and 1 patient during re-induction therapy on D+181. Seven patients are in complete response with 100% chimerism.

The median follow-up time of patients was 17.4 months (41 - 836days). Cumulative incidences of overall survival, event-free survival, relapse and non-relapse mortality at 27 months were 66.7%, 46.7%, 46.7% and 6.7% respectively.

Conclusions: LDE-etoposide based conditioning regimen of HSCT for AML has a clear-cut potential for being advantageously introduced in the clinical practice.

Disclosure: Nothing to declare.

P148 A Phase II Study to Investigate the Efficacy of short-term Everolimus in Addition to post-transplant Cyclophosphamide as graft-versus-host-prophylaxis after Allogeneic Stem Cell Transplantation (Octet-ever)

Udo Holtick1, Marco Herling1, Lukas P Frenzel1, Carmen Herling1, Joanna Schiller1, Marta Rebecca Cruz Aguilar1, Sebastian Theurich2, Michael Hallek1, Christof Scheid1

1Universität Köln, Köln, Germany, 2Universitätsklinikum Großhadern, Ludwig-Maximilians-Universität, München, Germany

Background: Conditioning regimens and the choice of immunosuppression have substantial impact on immune reconstitution after allogeneic hematopoietic stem cell transplantation (aHSCT). The pivotal mechanism to achieve and maintain remission in patients undergoing allogeneic transplantation is the induction of the graft-versus-tumor effect (GvT). Such GvT effects are not achieved in all patients transplanted and relapse is a common event. Moreover, graft versus host disease (GvHD) attacking the recipients’ healthy tissues often preceeds the development of the GvT effect and requires prolonged immunosuppressive therapy hereby abolishing the desired GvT effect. Classic immunosuppressive strategies implementing calcineurin inhibitors (CNI) hamper the immune recovery and built-up of the anti-cancer immune response.

Methods: We designed a phase II clinical study for patients with high-risk hematological malignancies using a CNI-free approach consisting of post-transplant cyclophosphamide and short-term everolimus, an immunosuppressant with anti-proliferative properties given from d+5 to d+100, after reduced-intensity conditioning and matched peripheral blood stem cell transplantation. Results after recruitment of all 19 patients planned will be presented.

Results: Nineteen patients with relapsed or refractory lymphoma and myeloma at high-risk for relapse underwent allogeneic peripheral blood stem cell transplantation with a matched related or unrelated donor after conditioning with fludarabine and busulfan. After application of post-transplant cyclophosphamide on d+3 and +4 after transplant, short-term everolimus was given from d+5 to d+100. Primary endpoint is the cumulative incidence and severity of acute GvHD. All patients presented a complete donor chimerism by d+30 and d+100. Engraftment was delayed with 17, 29 and 27 days for neutrophils, hemoglobin and platelets, respectively. The overall incidence of acute GvHD was 53%. Grade II aGvHD was found in 36% while none of the patients experienced grade III or IV aGvHD. In most cases aGvHD presented as cutaneous manifestation shortly after engraftment. The overall incidence of chronic GvHD was 21%, which was mild in all cases. Two patients died due to sepsis 18 and 20 days after transplant. One patient died due to secondary AML/ MDS three years after transplant. The cumulative incidence of non-relapse mortality on d+100 and d+365 was 11% with a median follow-up of 628 days (18-1152 days). There was one secondary graft failure. The cumulative incidence of relapse was 32% and 37% at one and two years after transplant, respectively. Relapse-free survival was 58% and 52% after one and two years. The overall survival was 73% and 64% after one and two years. All surviving patients are currently without cGvHD and immunsuppressive medication.

Conclusions: The use of post-transplant cyclophosphamide and short-term everolimus is safe with low rates of aGvHD, no severe aGvHD and a low incidence of mild cGvHD translating into a low rate of early non-relapse mortality. The relapse rates in this difficult to treat patient population are encouraging and warrant further studies using the combination of post-transplant cyclophosphamide and everolimus.

Clinical Trial Registry: Study protocol code: Uni-Koeln-1717 EudraCT number: 2013-005507-14

Disclosure: The study was supported by a research grant from Novartis to CS/UH. The other authors have no conflicts of interest to disclose.

P149 Allogeneic Stem Cell Transplantation in Patients ≥ 65 Years with Hematological Malignancies after Myeloablative treosulfan-based Conditioning: Results in 118 Patients

Simona Piemontese1, Lorenzo Lazzari1, Magda Marcatti1, Fabio Giglio1, Raffaella Greco1, Daniela Clerici1, Maria Teresa Lupo Stanghellini1, Andrea Assanelli1, Francesca Farina1, Francesca Lorentino1, Sara Mastaglio1, Sarah Marktel1, Matteo Carrabba1, Consuelo Corti1, Massimo Bernardi1, Jacopo Peccatori1, Fabio Ciceri1,2

1IRCCS San Raffaele Scientific Institute, Milan, Italy, 2University Vita-Salute San Raffaele, Milan, Italy

Background: Allogeneic hematopoietic stem cell transplantation (allo-SCT) remains the only potentially curative treatment for many hematological malignancies. For most of these, median age of occurrence is 60 years and even more. Nevertheless, the use of allo-SCT had been usually limited to a younger population because of concern related to non-relapse mortality (NRM) of older patients. We here report our large experience in allo-HSCT in patients diagnosed with hematological malignancies and older than 64 yrs.

Methods: From 2005 to 2019, 118pts older than 64yrs received a T-replete allo-SCT for acute leukemias (88pts, 75%), myelodysplastic syndromes (21pts, 18%) or others hematological malignancies (9pts, 7%) at our center. Donors were matched siblings in 19pts (16%), unrelated in 39pts (33%), haploidentical in 57pts (48%) and single cord blood unit in 3pts (3%). Median age at transplant was 67y (65-76). Seventy-seven patients (65%) were transplanted in early disease status (complete remission, CR, or upfront) while 41pts in active disease (35%). One-hundred and six patients out of 118 (90%) received a myeloablative treosulfan-fludarabine based conditioning regimen. Graft-versus-host-disease prophylaxis was sirolimus-based in 91 out of 118 pts (77%), cyclosporine-based in 27pts (23%). Post-transplant Cyclophosphamide was used in 68pts (58%), antithymocyte globulin in 41pts (35%).

Results: Median follow-up among survivors (63pts) was 35 months (3-104). All but two patients engrafted. Median time from transplant to engraftment was 21 days for neutrophils (11-50) and 24 days for platelets (9-632).

Overall survival (OS) at 1 and 3 years was 67+/-4% and 56+/-5%, respectively. Disease free survival (DFS) at 1 and 3 years was 62+/-5% and 46+/-5%, respectively. Day-100 NRM was 18+/-4%. The 1 and 3-year NRM was 26+/-4% and 36+/-5%, respectively. The 1 and 3-year cumulative incidence (CI) of relapse was 16+/-4% and 27+/-5%. Day-100 CI of acute GvHD grade II-IV was 41+/-5%, of grade III-IV was 15+/-3%. CI of overall cGvHD at 1 year was 30+/-5%, of extensive cGvHD was 19+/-4%. No differences in transplant outcomes were found in patients younger or older than 70yrs.

In multivariate analysis early disease status at transplant was the only risk factor associated to OS (HR 0.478; p=0.007. CI: 0.279-0.818), DFS (HR 0.435; p=0.001. CI: 0.262-0.722) and NRM (HR 0.433; p=0.011. CI: 0.227-0.823). The 3-year OS, DFS and NRM for patients transplanted in early disease status were as follows: 70+/-5%, 58+/-6% and 13+/-4%, respectively. Matched sibling donors were associated to lower CI of day-100 aGvHD in multivariate analysis (HR 0.538; p=0.023. CI: 0.316-0.918). Diagnosis of acute leukemia was the only risk factor associated to lower CI of cGvHD (HR 0.311; p=0.00044. CI: 0.162-0.597).

Conclusions: Based on our results we can conclude that age alone should not limit allo-SCT eligibility of patients with hematological malignancies, above all in early disease status. The use in the majority of our patients of treosulfan, an alkylating agent with a low toxic profile, could have contributed to the low incidence of NRM without negatively affecting long-term disease control.

Disclosure: Nothing to declare.

P150

Abstract already published.

P151 Fludarabine-melphalan Conditioning Results in Favorable leukemia-free Survival after Allogeneic Transplantation in Patients with Active or Measurable Residual AML

Kathryn Bower1, Madiha Siraj2, Jongphil Kim1, Biwei Cao1, Hany Elmariah1, Lia Perez1, Asmita Mishra1, Taiga Nishihori1, Farhad Khimani1, Rawan Faramand1, Aleksandr Lazaryan1, Hugo Fernandez3, Michael Nieder1, Dan Sullivan1, Joseph Pidala1, Claudio Anasetti1, Nelli Bejanyan1

1H Lee Moffitt Cancer Center and Research Institution, Tampa, FL, United States, 2University of South Florida, Tampa, FL, United States, 3Memorial Healthcare System, Pembroke Pines, FL, United States

Background: A recent large CIBMTR study demonstrated no survival benefit with use of myeloablative (MAC) compared to reduced-intensity conditioning (RIC) in patients receiving allogeneic hematopoietic cell transplant (alloHCT) for acute myeloid leukemia (AML) or myelodysplastic syndrome with high-risk disease risk index (DRI) (Bejanyan, ASH 2019). While commonly used MAC fludarabine-busulfan (FluBu) and RIC fludarabine-melphalan (FluMel) result in similar outcomes after alloHCT for AML in remission (Eapen, Blood Adv 2018), the preferred conditioning regimen for active or detectable residual (MRD+) AML at alloHCT remains unknown.

Methods: We analyzed outcomes of 125 patients with active (n=62) or MRD+ (n=63) AML who received alloHCT (2005-2017) with either MAC FluBu4 (72%) with PK-targeted IV daily average Bu AUC of 5300 or RIC FluMel (28%) with total Mel dose of 140 mg/m2.

Results: The group receiving FluMel had a higher proportion of >60-year-old patients (74% vs 21%, p< 0.001), adverse genetic risk AML by ELN 2017 (63 % vs. 51%, p=0.015), alloHCT performed from 2015-2017 (83% vs. 33%, p< 0.001) and Tacrolimus/ Sirolimus-based GVHD prophylaxis (86% vs. 50%, p=0.001). The rest of the characteristics were similar between FluBu and FluMel recipients, including the disease status at HCT (active AML, 54% vs. 37%, p=0.14). Probabilities of 2-year non-relapse mortality (NRM), relapse, leukemia-free survival (LFS) and overall survival (OS) are shown in the Figure. In multiple regression analysis after adjusting for disease status at alloHCT (active vs. MRD+) and DRI, the FluMel regimen compared to FluBu resulted in significantly lower risk of relapse (HR=0.26, 95% CI 0.11-0.63; p=0.003) and higher LFS (HR=0.49, 95% CI 0.28-0.86; p=0.014), but there was only a statistically non-significant trend of better OS (HR=0.57, 95% CI 0.32-1.02; p=0.06) (Table). NRM was similar between the two conditioning groups.

Conclusions: In conclusion, our data support the use of the RIC FluMel regimen for alloHCT in patients with MRD+ or active AML as it results in lower risk of relapse and better LFS compared to MAC FluBu. This study´s findings require confirmation in a larger cohort of patients with MRD+ and active AML.

NRMRelapseLFSOS
VariablesHR (95% CI)p valueHR (95% CI)p valueHR (95% CI)p valueHR (95% CI)p value
FluMel vs FluBu1.50 (0.71-3.17)0.290.26 (0.11-0.63)0.0030.49 (0.28-0.86)0.0140.57 (0.32-1.02)0.06
Active Disease vs MRD+2.18 (0.81-5.92)0.121.07 (0.44-2.60)0.891.40 (0.69-2.84)0.351.72 (0.84-3.52)0.14
High/Very High DRI vs Low/Intermediate DRI1.79 (0.68-4.71)0.243.11 (1.11-8.68)0.033.01 (1.40-6.51)0.0053.61 (1.64-7.95)0.0015

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[Multivariate Analysis of Clinical Outcomes]

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[Clinical outcomes of active or MRD+ AML patients by conditioning regimen]

Disclosure: Aleksandr Lazaryan- Eusa Pharma LLC scientific advisory board

The rest of the authors have nothing to declare.

P152 Sequential Conditioning: Flamsa-TBI versus flamsa-treo in High Risk Acute Myeloid Leukemia (AML) in First Complete Remission and High Risk Myelodysplastic Syndrome (MDS)

Elisa Sala, Verena Wais, Mai Thanh Nguyen, Adela Neagoie, Marie-Luise Hütter-Krönke, Andrea Gantner, Hartmut Döhner, Donald Bunjes

Ulm University Medical Center, Ulm, Germany

Background: Reduced Intensity Conditioning (RIC) regimens allowed allogeneic stem cell transplantation (allo-SCT) for patients with high risk hematological malignancies at advanced age and/or with comorbidities. In aggressive leukemia, RIC regimens may not be sufficient to control the disease, resulting in high relapse rates. The FLAMSA RIC regimen, that associates a short course of chemotherapy with a RIC backbone including TBI 4Gy, reported encouraging results in the treatment of high risk AML and MDS. Still the original protocol is associated with acute toxicity, mainly due to TBI. In this context Treosulfan is being investigated at different dosages as an attractive alternative in order to ameliorate the toxicity profile, preserving the anti-leukemic activity in a high risk population.

Methods: We substituted in the FLAMSA protocol (Schmid, JCO 2005) the TBI with Treosulfan 12g/m2/d from day -6 to -4 (FLAMSA-Treo). A retrospective comparison was then performed between FLAMSA-TBI and FLAMSA-Treo considering patients with high risk AML in first Complete Remission (CR1) and high-risk MDS. The high risk status was defined according to molecular markers, karyotype, delayed response to induction chemotherapy, and AML secondary to MDS or previous chemotherapy. Standard risk AML patients in molecular relapse after standard treatment were also considered “high risk”. The decision to treat patients with FLAMSA-Treo instead of FLAMSA-TBI conditioning was at the physician’s board discretion according to TBI availability, patient age and/or presence of comorbidities.

Results: Between 01/2006 and 06/2019 a total of 59 patients with high risk AML in CR1 (n=53) and high risk MDS (n=6) received allo-SCT after a FLAMSA conditioning. Out of 59 patients, in 45 (76%) a FLAMSA-TBI protocol was administered, while in the remaining 14 (24%) Treosulfan replaced TBI. All the patients, except three, received PBSC as source of transplantation. The GvHD Prophylaxis was based on a combination between CyclosporinA and Mycophenolate Mofetil. Further Patients’ characteristics are listed in Figure 1a. Comparing the outcome of the two subpopulations (TBI vs Treo), no significant differences were observed in terms of OS (1yOS 73% vs 90% respectively, p=0.15), TRM (1yTRM, 45% vs 7%, p=0.3) and relapse incidence (1yRI 22% vs 20%, p=0.4). Considering that we introduced the FLAMSA-Treo platform mostly in the last two years (13/14 pts) and in order to minimize potential biases related to the year of transplantation, we performed a time driven sub-analysis, including only patients transplanted since 01/2017 in both cohorts (n=23, TBI n=10, Treo n=13). In this context, Treosulfan proved to confer a survival advantage to TBI-based conditioning (1yOS 92% vs 50%, p=0.05), manly due to a reduction in the transplant related mortality (1yTRM 8% vs 40%, p=0.09).

Conclusions: In our analysis the Treosulfan-based FLAMSA protocol demonstrated a favorable toxicity profile, at least not inferior to the standard platform including TBI, for the treatment of high risk AML/MDS older patients and/or with comorbidities. The reduced toxicity profile of Treosulfan could favor especially AML patients in first complete remission. A larger prospective series of patients is needed in order to confirm these promising preliminary findings.

Disclosure: Sala E: Honoraria with Gilead.

P153 Increased non-relapse Mortality and Poor Overall Survival in Elderly Patients Treated with Fludarabine and Myeloablative Dose of Busulfan: Transplant Complications Working Group of the JSHCT

Akihito Shinohara1, Michiho Ebihara1, Nobuaki Nakano2, Emiko Sakaida3, Naoyuki Uchida4, Kentaro Fukushima5, Hitoshi Sakai6, Takashi Ashida7, Yoshinobu Kanda8, Junji Tanaka1, Takahiro Fukuda9, Yoshiko Atsuta10,11, Hideki Nakasone8

1Tokyo Women’s Medical University, Tokyo, Japan, 2Imamura General Hospital, Kagoshima, Japan, 3Chiba University Hospital, Chiba, Japan, 4Federation of National Public Service Personnel Mutual Aid Associations, Toranomon Hospital, Tokyo, Japan, 5Osaka University Hospital, Osaka, Japan, 6Shinshu University, Nagano, Japan, 7Kindai University Hospital, Osaka, Japan, 8Jichi Medical University Saitama Medical Center, Saitama, Japan, 9National Cancer Center Hospital, Tokyo, Japan, 10Japanese Data Center for Hematopoietic Cell Transplantation, Aichi, Japan, 11Nagoya University, Aichi, Japan

Background: Fludarabine and a myeloablative dose of intravenous busulfan (Flu/Bu4) are widely used together in allogeneic hematopoietic stem cell transplantation (alloHSCT) as a reduced-toxicity conditioning regimen. Although Flu/Bu4 has been applied to a wide range of age groups, the increasing number of transplant-related complications observed among elderly patients remains a major concern.

Methods: We conducted a retrospective survey of alloHSCT in Japan, using the transplant outcomes registry database maintained by the Transplant Registry Unified Management Program. The following inclusion criteria were applied: patients >15 years old with hematological malignancies who had received their first alloHSCT between 2006 and 2017, and who were treated with Flu/Bu4 (total intravenous busulfan dose of 11.2-16 mg/kg or equivalent). Patients who received total body irradiation (TBI) or other chemotherapeutic drugs were also included. Patients who received alloHSCT from cord-blood donors were excluded.

Results: The median age of patients was 58 years (range 16-80), and 43.4% of patients were 60 years or older. Of 1,443 patients, 62.6% were male. Patients were diagnosed with myeloid malignancies (87.1%), lymphoid malignancies (9.1%), and other malignancies (3.0%). Approximately two-third of the patients (66.4%) received bone marrow transplantation, and 584 (25.5%) and 830 (36.3%) patients received alloHSCT from matched related donors and 8/8 matched unrelated donors. The 5-year overall survival (OS) rate after alloHSCT was 45.5% (95% confidence interval [CI]: 42.3.5%-48.6%) for the young group (< 60 years) and 34.8% (95% CI: 31.2%-38.5%) for the elderly group (≥60 years). Although the 5-year cumulative incidence of relapse was equivalent between the two groups (P = 0.67, 32.7% and 33.8%, respectively), the 5-year non-relapse mortality (NRM) was significantly higher for the elderly group (34.0%) than for the young group (25.0%) (P < 0.01). According to the multivariate analysis, increased patient age (≥60 years) was associated with an increased risk of poor OS (hazard ratio [HR] 1.33, 95% CI: 1.19-1.49, P < 0.01) and poor NRM (HR 1.40, 95% CI: 1.19-1.65, P < 0.01). In the subgroup analysis of the elderly group, advanced diseases, administration of chemotherapeutic drugs in addition to Flu/Bu4, and poor performance status (>0) were significant risk factors for poor OS. Those patients who received chemotherapeutic drugs in addition to Flu/Bu4 experienced thrombotic microangiopathy and bleeding complications more frequently than those who did not (P < 0.01 for both comparisons); however, no significant differences were observed for primary causes of death. Nearly half of the elderly patients received TBI with Flu/Bu4. No significant difference in the OS was observed between patients treated with and without TBI; however, TBI resulted in significantly increased NRM (P < 0.01). Elderly patients treated with TBI experienced sinusoidal obstruction syndrome (P < 0.01) and bleeding complications (P = 0.04) more frequently than those treated without TBI.

Conclusions: Flu/Bu4 for elderly patients was associated with increased NRM, resulting in poor OS. In particular, the administration of additional chemotherapeutic drugs or TBI in combination with Flu/Bu4 in elderly patients increased the incidence of certain complications, which might be associated with poor NRM. Therefore, Flu/Bu4 should be used with caution in elderly patients.

Clinical Trial Registry: Not applicable

Disclosure: The authors declare. no conflict of interest. This work was supported in part by the Practical Research Project for Allergic Diseases and Immunology (Research Technology of Medical Transplantation) from Japan Agency for Medical Research and Development, AMED.

P154 Total Marrow and Lymphoid Irradiation (TMLI) in Combination with Cyclophosphamide and Etoposide improves the Outcome of Patients with poor-risk Acute Leukemia

Anthony Stein, Ni-Chun Tsai, Joycelynne Palmer, Ibrahim Aldoss, Haris Ali, Ahmed Aribi, Len Farol, Chatchada Karanes, Samer Khaled, An Liu, Guido Marcucci, Ryotaro Nakamura, Vinod Pullarkat, Eric Radany, Joseph Rosenthal, Amandeep Salhotra, Ricardo Spielberger, David S Snyder, Stephen J Forman, Monzr M Al Malki, Jeffrey Wong

City of Hope, Duarte, CA, United States

Background: Total marrow and lymphoid irradiation (TMLI) delivers augmented doses of radiation to the bone marrow while maintaining low doses to vital organs. We have conducted a phase II study in which we combined TMLI with cyclophosphamide (Cy) and etoposide (VP16) as a conditioning regimen to evaluate its anti-leukemia activity and safety/tolerability in patients with relapsed/refractory acute leukemia. We report here on 57 patients with a median of more than one year of follow-up.

Methods: TMLI (2000cGy to targets, 1200cGy to liver/brain) was administered on days -9 to -5, VP16 60mg/kg (adjusted body weight) on day -4, and Cy 100mg/kg (ideal body weight) on day -2. Bone marrow (n=6) or peripheral blood stem cells (n=51) were given on day 0. Graft versus host disease (GVHD) prophylaxis used was tacrolimus and sirolimus. The primary endpoint was progression free survival (PFS), and secondary endpoints included overall survival (OS), non-relapse mortality (NRM), and toxicity.

Results: Of the 57 patients (Table) with a median of at least 1 year of follow up, the median follow up was 12.5 months (range 1.1-48.3). Engraftment was noted for all patients. The CR/CRi rate at day +30 was 100% for the 56 patients with available data. Disease relapse/progression at 1 year was 47% (95%CI: 35-62). The estimates of NRM at 100 days and 1 year were 4% (95%CI: 1-14) and 6% (95%CI: 2-17), respectively. Relapsed disease after transplant occurred in 34 patients (60%). Four patients died in remission because of infections (n=2), West Nile encephalitis, and cGVHD.

One-year estimates of OS and PFS were 67% (95%CI: 53-78) and 48% (95%CI: 34-60), respectively. The OS/PFS of patients with a Duval score of ≥2 (i.e., high risk) was not statistically significantly different than those associated with a score < 2.

Grade ≥2 Bearman toxicities were bladder (Gr2 n=2), central nervous system (Gr2 n=1), gastrointestinal (Gr2 n=4), hepatic (Gr2 n=1, Gr3 n=1), pulmonary (Gr2 n=1), and renal (Gr2 n=2, Gr3 n=2). Grade 2 and 3 stomatitis occurred in 12 and 2 patients, respectively. There were no grade 4 toxicities or toxicity-related deaths. Acute GVHD was manageable and consistent with previous experience with the regimen.

Conclusions: 1) TMLI can be safely delivered in combination with VP16 and Cy, with NRM rates < 10%; 2) The regimen is effective for patients with relapsed/refractory acute leukemia; 3) Patient outcomes are superior over traditional rates as reported by Duval et al (Duval et al., J Clin Oncol 2010, pp.3730-9).

VariableMedian(range) or N(%)
Age at transplant (yrs)40(16-59)
Prior regimens3(1-7)
Disease diagnosis: AML, ALL43(75), 14(25)
Disease status at alloHCT: 1RL, 2RL, IF18(32), 4(7), 35(61)
Donor source: Sibling26(46)
Matched unrelated, mismatched (9/10) unrelated5(9), 26(45)
% Blasts in bone marrow, blood* at baseline25(0**-95), 17.5(1-83)
Cytogenetics at baseline: ALL: Intermediate, Adverse, Unknown7(12), 6(11), 1(2)
AML: Favorable, Intermediate, Adverse1(2), 16(28), 26(45)

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[Patient characteristics. *28 patients had 0% and were excluded. **5 patients had extramedullary disease.]

Clinical Trial Registry: NCT02094794

Disclosure: Anthony Stein: Stemline: Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Celgene: Speakers Bureau.

Joycelynne Palmer: Gilead Sciences: Consultancy.

Haris Ali: Incyte: Consultancy, Speakers Bureau.

Ibrahim Aldoss: Jazz Pharmaceuticals: Honoraria, Other: travel/accommodation/expenses, Speakers Bureau; Agios: Consultancy, Honoraria; Helocyte: Consultancy, Honoraria, Other: travel/accommodation/expenses; AUTO1: Consultancy.

Ryotaro Nakamura: Kirin Kyowa: Other: support for an academic seminar in a university in Japan; Merck: Membership on an entity´s Board of Directors or advisory committees; Celgene: Other: support for an academic seminar in a university in Japan; Alexion: Other: support to a lecture at a Japan Society of Transfusion/Cellular Therapy meeting

Amandeep Salhotra: Celgene: Other: Research Support; Kadmon Corporation: Other: Non paid consultant. Ali: Incyte: Consultancy, Speakers Bureau.

P155 A CD45-targeted Antibody Drug Conjugate Enables Allogeneic Hematopoietic Stem Cell Transplantation as a Single Agent in Mice

Sharon Hyzy1, Rahul Palchaudhuri1, Jennifer Proctor1, Bradley Pearse1, Ganapathy Sarma1, Geoff Gillard1, Asim Saha2, Tahirih Lamothe1, Melissa Brooks1, Katelyn Hammond1, Anjali Bhat1, Charlotte McDonagh1, Hans-Peter Kiem3, John Wagner2, Bruce Blazar2, Anthony Boitano1, Michael Cooke1

1Magenta Therapeutics, Cambridge, MA, United States, 2University of Minnesota, Minneapolis, MN, United States, 3Fred Hutchinson Cancer Research Center, Seattle, WA, United States

Background: Allogeneic hematopoietic stem cell transplant (Allo-HSCT) is a potentially curative treatment for malignant and non-malignant blood disorders. However, current conditioning regimens limit the use of this curative procedure due to conditioning-related mortality and morbidities. As a result, many patients are not able do not undergo this potentially curative therapy. We developed a novel antibody drug conjugate (ADCs) to provide a readily translatable approach that is fully myeloablative as a single agent while reducing the toxicity associated with current conditioning agents. We have generated an anti-mouse CD45 ADC to model this approach for conditioning recipients for minor mismatch and fully allogeneic HSCT.

Methods: Our tool CD45 ADC is engineered for rapid clearance (T1/2=1.7hr) to enable HSCT after conditioning, and a single dose of 3 mg/kg is fully myeloablative. To determine if the tool CD45-ADC could successfully condition recipients for minor histocompatibility antigen mismatched allo-HSCT, we used a single dose of the tool CD45-ADC to condition DBA/2 hosts (H-2d, CD45.2+) for transplant with CByJ.SJL(B6) mice (H-2d, CD45.1+). A matched dose of non-targeted isotype ADC (Iso-ADC) was used as a negative control, while 9 Gy TBI was used as the conventional conditioning positive control. To determine if the tool CD45 CD45-ADC could successfully condition recipients for fully mismatched allo-HSCT, we compared the ability of a single dose of the tool CD45-ADC, alone or supplemented with various levels of TBI, to condition C57BL/6 hosts (H-2b, CD45.2+) for transplant with cells from CByJ.SJL(B6) mice. We used matched doses of Iso-ADC with and without supplemental TBI and 9 Gy TBI as controls. In both studies, conditioned mice were transplanted with 2x107 whole BM cells, and peripheral chimerism was monitored over 16 weeks.

Results: In the minor mismatch (Balb/c CD45.1+→DBA/2 CD45.2+) model of allogeneic HSCT, a single dose of the tool CD45-ADC enabled full donor chimerism through 12 weeks as a single agent (Figure 1A); >90% donor chimerism was observed in T-, B-, and myeloid lineages, comparable to 9 Gy TBI conditioning. Treatment with a matched dose Iso-ADC was not effective. In the fully mismatched Balb/c → C57Bl/6 allo-HSCT model, CD45-ADC as a single agent enabled partial, transient chimerism at 3 weeks post-transplant; an iso-ADC did not. With CD45-ADC as the primary agent, supplementation with TBI doses as low as 0.5 Gy enabled durable full donor chimerism (Figure 1B), comparable to 9 Gy TBI alone. Iso-ADC required a minimum supplementation of 4 Gy TBI to enable donor chimerism.

Conclusions: Conditioning with CD45-ADC is fully myeloablative and enables complete chimerism in a minor mismatch allo-HSCT model as a single agent and enables complete chimerism in the full mismatch allo-HSCT model when supplemented with low dose (0.5 Gy) TBI. This targeted, readily translatable approach for safer conditioning could improve the risk-benefit profile for allogenic and haploidentical HSCT and may extend the curative potential of HSCT to more patients suffering from blood cancers and other diseases that may benefit from HSCT.

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[Figure 1]

Disclosure: Sharon Hyzy- Ownership Interest and Salary, Magenta Therapeutics

Rahul Palchaudhuri- Ownership Interest and Salary, Magenta Therapeutics

Jennifer Proctor- Ownership Interest and Salary, Magenta Therapeutics

Bradley Pearse- Ownership Interest and Salary, Magenta Therapeutics

Ganapathy Sarma- Ownership Interest and Salary, Magenta Therapeutics

Geoff Gillard- Ownership Interest and Salary, Magenta Therapeutics

Asim Saha- Nothing to declare.

Tahirih Lamothe- Ownership Interest and Salary, Magenta Therapeutics

Melissa Brooks- Ownership Interest and Salary, Magenta Therapeutics

Katelyn Hammond- Ownership Interest and Salary, Magenta Therapeutics

Anjali Bhat- Ownership Interest and Salary, Magenta Therapeutics

Nicholas Clark- Ownership Interest and Salary, Magenta Therapeutics

Charlotte McDonagh-- Ownership Interest and Salary, Magenta Therapeutics

Hans-Peter Kiem- Nothing to declare.

John Wagner- Consultant, PI (Magenta Therapeutics); Board Member (Gadeta); PI (BlueRock); Consultant (Rocket Pharma); PI (Novartis)

Bruce Blazar- Advisory Board Member (Kamon Pharmaceuticals, Five Prime Therapeutics, Regeneron Pharmaceuticals, Magenta Therapeutics, BlueRock Therapeutics); Research support (Fate Therapeutics, RXi Pharmaceuticals, Alpine Immune Sciences, Abbvie, BlueRock Therapeutics, Leukemia and Lymphoma Society, Childrens´ Cancer Research Fund, KidsFirst Fund); Co-Founder (Tmunity)

Anthony Boitano- Ownership Interest, Royalty and Salary (Magenta Therapeutics)

Michael Cooke- Ownership Interest and Salary (Magenta Therapeutics)

P156 Final Results of a Prospective, Multicenter, non-interventional Study on thiotepa-based Autologous Hematopoietic Cell Transplantation (ASCT) for CNS or non-CNS Lymphoma

Herbert Gottfried Sayer1, Mathias Witzens-Harig2, Mohammad Wattad3, Agnieszka Korfel4, Inken Hilgendorf5, Georg-Nikolaus Franke6, Gerald Illerhaus7, Michael Heinsch8, Bernd Metzner9, Eva Bettina Zinngrebe10, Nadezda Basara11, Mascha Binder12, Mark Ringhoffer13, Alexander Röth14, Thomas Geer15, Volker Schmidt1, Peter Dreger2

1Helios Klinikum Erfurt, Erfurt, Germany, 2Universitätsklinik Heidelberg, Heidelberg, Germany, 3Klinikum Essen Süd, Essen-Werden, Germany, 4Universitätsmedizin Berlin, Berlin, Germany, 5Universitätsklinikum Jena, Jena, Germany, 6Universitätsklinikum Leipzig, Leipzig, Germany, 7Klinikum Stuttgart, Stuttgart, Germany, 8Helios Klinikum Duisburg, Duisburg, Germany, 9Klinikum Oldenburg, Oldenburg, Germany, 10Evangelisches Krankenhaus Bielefeld, Bielefeld, Germany, 11Malteser Krankenhaus Flensburg, Flensburg, Germany, 12Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany, 13Städtisches Klinikum Karlsruhe, Karlsruhe, Germany, 14Universitätsklinikum Essen-Duisburg, Essen, Germany, 15Diakonissen-Klinik Schwäbisch-Hall, Schwäbisch-Hall, Germany

Background: Thiotepa-containing high-dose chemotherapy (HDCT) followed by ASCT is considered as standard of care in the treatment of primary or secondary central nervous system lymphoma (PCNSL/SCNSL) based on its capacity to penetrate the blood-brain barrier. In order to collect data in daily practice, this prospective, multicenter, non-interventional study was initiated to evaluate thiotepa-based HDCT prior to ASCT in patients with PCNSL or SCNSL, or non-CNS lymphoma: non-Hodgkin or Hodgkin lymphoma (NHL, HL). Primary aims of this study were assessment of safety and efficacy of thiotepa-based high-dose regimens in ASCT for lymphoma.

Methods: Eligible patients were 18 years of age or older and were assigned to undergo ASCT after HDCT either with thiotepa 20 mg/kg, BCNU 400 mg/m² +/- etoposide 450 mg/m² (TT+BCNU) for PCNSL/SCNSL; or thiotepa 10 mg/kg, etoposide 800 mg/m², araC 1600 mg/m², melphalan 140 mg/m² (TEAM) for non-CNS lymphoma (B-/T-NHL, HL). Primary endpoints were toxicity and efficacy. Data were documented at 4 time-points: before therapy, at day 30, day 100 and 1 year post ASCT.

Results: From Oct 2013 to Apr 2017, 83 patients were registered by 16 centers, of whom 80 [51 male,] had a complete dataset available and were included in this analysis. Median age was 59 years (range: 22-78), with 12 patients being older than 65 years. T+BCNU and TEAM were used in 44 (55%) and 33 (41%) patients, respectively, and other combinations in the 3 remaining patients. Diagnosis was PCNSL in 32 (40%) patients, SCNSL in 13 (16%) patients, and NHL/HL) without CNS involvement in 35 (44%) patients. Main non-hematological grade 3-4 organ toxicities up to day +30 were mucositis, diarrhea, infection, and fever, occurring in 67%, 21%, 47%, and 16%, respectively, of all 80 patients. Neutrophil recovery (>500/µl) occurred at a median of 10 days (4-21), and platelet recovery (>20.000/µl) at a median of 13 days after transplantation. Non-relapse mortality at day +100 and 1 year was 8.8% corresponding to non-adjusted 7 fatalities, all infection related with no impact of underlying disease, thiotepa regimen used, and age. On day 100, 72 patients were evaluable for response, here 42 (53%) achieved complete response, 20 (25%) partial response and 3 (4%) patients stable disease. Nineteen (24%) patients experienced relapse/progression, translating into a progression-free survival at one year of 68% (PCNSL: 78%; SCNSL: 54%; B-/T-NHL, HL: 63%), and an overall survival of 78% (PCNSL: 81%; SCNSL: 69% and B-/T-NHL, HL: 77%). No difference of therapy outcome could be detected in patients being < or > 60 years, but a worse PFS and OS for patients older than 65 years.

Conclusions: The results of this prospective study suggest that thiotepa-based high-dose chemotherapy for ASCT for both CNS and non-CNS lymphoma is effective and does not raise safety concerns compared to other HDCT regimens commonly used for ASCT of lymphoma across all age groups.

Clinical Trial Registry: CTU82G

Disclosure: Herbert G. Sayer: Honoria from RIEMSER Pharma GmbH

P157 Post-Transplant Cyclophosphamide (PT-CY), Cyclosporin (CSA) and Mycophenolate (MMF) for Patients Grafted from HLA Identical Siblings or Matched Unrelated Donors

Andrea Bacigalupo1, Patrizia Chiusolo1, Federica Sora1, Luca Laurenti1, Sabrina Giammarco2, Elisabetta Metafuni2, Idanna Innocenti2, Francesco Autore2, Alessia Di Giovanni2, Eleonora Alma2, Silvia Bellesi2, Simona Sica1

1Universitá Cattolica del Sacro Cuore, Roma, Italy, 2Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy

Background: GvHD remain a significant complication in HLA matched grafts, receiving prophylaxis with cyclosporin (CSA), methotrexate (MTX), also when combined with anti-thymocyte globulin (ATG). In a prospective study the triple combination of post-transplant cyclophosphamide (PT-CY), CSA and mycophenolate (MMF), has shown to provide the best protection against GvHD in HLA matched transplants (Bolanos, Lancet Haematol, 2019)

Methods: To assess the outcome of HLA matched grafts receiving GvHD prophylaxis with PTCY+CSA+MMF or ATG+CSA+MTX, we retrospectively analyzed the outcome of 113 HLA identical transplants grafted from identical siblings (SIBS) (n=58) or 8/8 allelic matched unrelated donors (MUD) (n=55). GvHD prophylaxis was PTCY based in 28 and ATG based in 85.

The median age was borderline lower in the PTCY arm (48 vs 53 years, p=0.08). The conditioning regimen for 82% of patients in both arms, was thiotepa (10 mg/kg), busulfan 9.6 mg/kg and fludarabine 150 mg/m^2 (TBF); full dose TBI (12 Gy) was given to 4% of the ATG based patients and 14% of the PTCY based patients (p=ns). The disease phase was equally distributed in the two groups. Acute leukemia was the most frequent diagnosis in 48% and 46% of patients respectively, followed by MDS in 19% and 16% and myelofibrosis in 14% and 17%. Peripheral blood was the graft source for all patients.

Results: Median time to neutrophils 0.5x10^9/l was day 16 vs 18 days in the ATG vs PTCY patients (p=0.01). The proportion of patients with grade 0 acute GvHD was 25% for ATG and 94% for PTCY (p=0.00001); GvHD grade II developed in 19% vs 5% respectively an grade III-IV in 2% vs 0% (p=0.002). Chronic GvHD was absent in 54% vs 96% of ATG vs PTCY patients, and moderate severe cGvHD was diagnosed in 27% vs 0% (p=0.0008). TRM was documented in 22% vs 7% of ATG vs PTCY patients (p=0.07). Follow up is too short to analyzed relapse and survival. We compared matched grafts receiving the triple PTCY based GvHD prophylaxis, with a large concurrent group of HAPLO mismatched family grafts receiving the same prophylaxis (n=105): the incidence of GvHD grade II-IV was 21% in the HAPLO grafts and 3% in the matched grafts (p=0.01), given the same GvHD prophylaxis. Similarly cGvHD (moderate severe) was diagnosed in 19% of HAPLO grafts vs 0% of matched grafts (p=0.0009).

Conclusions: Data suggest that for HLA matched transplants, a triple PTCY based -GvHD prophylaxis is significantly superior to a triple ATG based -GvHD prophylaxis, in protecting patients from acute and chronic GvHD and results in a low TRM. It also suggests that, given the same PTCY based prophylaxis, GvHD is less frequent in matched related and unrelated grafts as compared to HAPLO mismatched grafts, reassessing the role of HLA matching in allogeneic transplants. We need to determine whether relapse is not increased given the extremely low incidence of GvHD, with the triple PTCY based GvHD prophylaxis in matched grafts. However, if these results can be reproduced, we may find out that HLA matching returns as a major predictor of GvHD.

Disclosure: No disclosures

P158 Conditioning Regimen Comparison for Allogeneic Stem Cell Transplantation in non-hodgkin Lymphoma

Kristen Peterson, Andrew Lin, Josel Ruiz, Junting Zheng, Sean Devlin, Gunjan Shah, Michael Scordo, Craig Sauter, Miguel Perales, Sergio Giralt, Larry Buie, Parastoo Dahi

Memorial Sloan Kettering Cancer Center, New York, NY, United States

Background: Allogeneic hematopoietic cell transplantation (allo-HCT) allows for the possibility of cure for patients (pts) with non-Hodgkin Lymphoma (NHL) as it provides an immunologic graft-versus-lymphoma effect. Non-relapse mortality (NRM) was felt to be prohibitive with myeloablative regimens, but technical advances with the advent of reduced-intensity conditioning (RIC) or nonmyeloablative (NMA) regimens have decreased these rates. RIC regimens are generally associated with more toxicity and higher NRM than NMA regimens. Though studies showed both approaches are safe and effective, there is lack of direct comparison between these different intensities of in NHL.

Methods: This retrospective study identified patients aged ≥ 18 years who underwent allo-HCT for relapsed/refractory NHL between 3/2008-6/2017 at our center. Outcomes were compared between pts who received NMA and RIC conditioning, with intensity delineated per CIBMTR definitions. Progression-free survival (PFS) was the primary outcome. Secondary outcomes included overall survival (OS) and non-relapse mortality (NRM). Additional outcomes included rates of acute GVHD at Day 100, chronic GVHD, and CMV reactivation at Day 100. Regimen intensity and other variables significant by univariate analysis were included in the multivariate analysis.

Results: For the 144 patients identified, the median age was 56 years (range, 19-79). More pts received NMA regimens (n=80, 56%) and most did not undergo prior autologous HCT (n=103, 72%). NMA regimens were given more frequently to pts with indolent B-cell lymphoma and were more likely to receive ATG and/or rituximab (p = 0.008, p < 0.001, and p < 0.001, respectively). At a median overall follow-up of 57.8 months (range 49 - 75.1) neither median PFS or OS were reached. In univariate analysis, NMA conditioning was associated with a longer PFS than RIC [HR 1.9 (1.11-3.24), p = 0.019). No difference in OS when comparing NMA and RIC regimens [HR 1.56 (0.85-2.85), p = 0.15). There was an increase in all grades of aGVHD [HR 3.68 (2.16, 6.28), p < 0.001)] with RIC regimens, but only 12 events of grade III/IV aGVHD overall.

In multivariate analyses (with histology and ATG as covariates) NMA with rituximab had improved PFS compared to RIC without rituximab [HR 0.43 (95% CI 0.22, 0.81; p=0.009)]. However, PFS was similar comparing NMA and RIC groups [HR 0.72 (95% CI 0.37, 1.41; p=0.3)]. Similarly, aGVHD (any grade) risk was lower in NMA pts receiving rituximab compared to RIC pts who did not [HR 0.15 (0.07-0.32), p < 0.001). No significant differences were noted in NRM or CMV reactivation between groups.

Conclusions: Our study suggests that there are comparable and favorable outcomes between RIC and NMA conditioned allo-HCT for NHL with careful patient and regimen selection. Further studies are needed to better define specific criteria in choosing between NMA and RIC allo-HCT conditioning regimens for pts with NHL.

Disclosure: Gunjan Shah- Investigator + Research Funding for Janssen and Amgen

Michael Scordo- Consultancy: McKinsey & Company + Angiocrine Bioscience

Craig Sauter- Advisory Board, Honoraria and Research Funding: Juno + Sanofi-Genzyme + Celgene + Precision Biosciences. Advisory Board and Honoraria: Spectrum Pharmaceuticals + Novartis + Genmab + Kite + Gamida + Pfizer + GSK

Miguel Perales- MolMed: Advisory Board and Honoraria + NexImmune: Advisory Board and Honoraria + Abbvie: Advisory Board and Honoraria + Bellicum: Advisory Board and Honoraria + Bristol-Myers Squibb: Advisory Board and Honoraria + Incyte: Advisory Board, Honoraria and Research Funding + Nektar Therapeutics: Advisory Board and Honoraria + Novartis: Advisory Board and Honoraria + Omeros: Advisory Board and Honoraria + Takeda: Advisory Board and Honoraria + Kite: Research Funding + Merck: Consultancy and Honoraria + Servier: DSMB Honoraria + Medigene: DSMB Honoraria

Sergio Giralt - Amgen: Consultant and Investigator, Research Funding + Actinium: Consultant and Investigator, Research Funding + Celgene: Consultant and Investigator, Research Funding + Johnson & Johnson: Consultant and Investigator, Research Funding + Miltenyi: Investigator, Research Funding + Takeda: Consultant and Investigator, Research Funding + Consultant for Kite + Spectrum Pharmaceuticals + Jazz Pharmaceuticals + Novartis

P159 A Thiotepa Based Intensified Reduced Intensity Conditioning Regime in Adult Cord Blood Transplant is a Promising Alternative in Patients Unable to Receive Myeloablative Conditioning

Ian Wu1, Tangia Muquith1, Yeh Ching Linn2, Michelle Poon1, Lip Kun Tan1, Belinda Tan1, Yelly Yelly1, Teck Guan Soh1, Davanaliz Gonzales Ramos1, William Hwang2, Liang-Piu Koh1

1National University Cancer Institute, National University Health System, Singapore, Singapore, 2Singapore General Hospital, Singapore, Singapore

Background: High relapse and graft failure rates have been seen with the Minnesota reduced-intensity conditioning (RIC) for umbilical cord blood transplantation (UCBT) regimen consisting of fludarabine (Flu) 200mg/m2, cyclophosphamide (Cy) 50mg/kg and 2 Gy of total body irradiation (TBI). We evaluated a new thiotepa-based intensified RIC regimen consisting of Flu 150mg/m2, Cy 50mg/kg, thiotepa 10mg/kg, and 4Gy TBI, which has shown promising results with sustained engraftment and acceptable toxicity.

Methods: We performed a retrospective analysis of 90 adult patients in 2 institutions in Singapore receiving 4/6-6/6 HLA matched UCBT for various haematological malignancies between Aug 2006 and May 2019. Patients received 1 of 3 conditioning regimens - myeloablative Conditioning (MAC, n=56) regimen of Flu 90mg/m2, Cy 120mg/kg and 12 Gy TBI, standard reduced intensity conditioning (s-RIC, n=20) and thiotepa-based intensified reduced intensity conditioning (i-RIC, N=14) regimen.

Results: There was no significant difference in the median day to neutrophil engraftment among the 3 groups (p=