Thiotepa-Based Conditioning Regimen Compared to Non-Thiotepa Conditioning Regimen Prior to Allogeneic Stem Cell Transplantation in β Thalassemia Major: Impact on Survival

Abstract This study is to investigate the survival impact of thiotepa as part of the conditioning therapy for β thalassemia major (TM) patients, undergoing HSCT from haploidentical and sibling cord blood transplant. We retrospectively analyzed 262 transplant patients and compared outcomes between Cyclophosphamide -fludarabinebusulfan - thiotepa (with TT group)and Cyclophosphamide fludarabine -busulfan(without TT group) regimens from July 2014 to July 2018. Transplantation was performed from 86 matched sibling (32.8%), 103 unrelated (39.3%) ,13 matched parent(5%), 41 haploidentical (15.6%), and 19 sibling cord blood (7.3%) donors, with a median follow-up of 27 months(1months-72months) and median age of 7 years old(2 ys-18ys). The overall survival (OS), thalassemia free survival (TFS), graft rejection (GR) and transplantation related mortality (TRM) among TT group and without TT group in matched sibling transplant patients was 97.6%, 97.6%, 0%, 2.4% and91.6%, 91.6%, 0%, 8.4% (P=0.355 in TFS), respectively; in unrelated transplant patients was 97.9%, 97.9%, 0%, 2.1% and 95.2%,93.3%, 1.9%, 4.8% (P=0.256 in TFS), respectively; in matched parent transplant was 90.9%, 90.9%, 0%, 9.1% and 100%. 100%, 0%, 0%;( P=0.546 in TFS), respectively; whereas, in haploidentical transplant was 100%, 96.9%, 3.1%, 0% and 88.9%, 77.8%, 12.5%, 11.1%(P=0.043 in TFS); and in sibling cord blood transplant was 100%, 100%, 0%, 0% and 100%, 62.3%, 29.9%, 0% (P=0.035 in TFS). Our data suggest that thiotepa-based conditioning regimen in TM is effective and safe and survival outcome of thiotepa-based regimen in haploidentical transplant and sibling cord blood transplant are encouraging. Thiotepa-based regimen may improve survival outcome in haploidentical transplant and sibling cord blood transplant. Figure. Figure. Disclosures No relevant conflicts of interest to declare.