Comparison of myeloablative vs reduced intensity conditioning regimens in stem cell transplantations for acute myeloid leukemia.

e18518 Background: The development of reduced intensity conditioning (RIC) regimens enabled allogeneic hematopoietic stem cell transplantations (allo-HSCT) also for patients who had contraindications and comorbidities for myeloablative conditioning (MAC) regimens. The aim of this study is to evaluate the effects of conditioning regimens on outcomes of alllo-HSCT for patients with acute myeloid leukemia. Methods: We retrospectively analysed 362 acute myeloid leukemia patients who underwent allo-HSCT between November 1989 to November 2016. We compared the outcomes of MAC vs RIC by Fisher’s test and chi-square test. Results: Engraftment was achieved in 87% of RIC and 95% of MAC recipients (p = 0.03).Incidences of acute and chronic graft vs host disease were not statistically different in groups (41% vs 47%, p = 0.7; 32% vs 43%, p = 0.2).Relapse rate was higher in RIC group (45% vs 25%, p = 0.02).Both 1-year overall survival (OS) and 1-year relapse free survival (RFS) rate were lower in the patients treated with RIC (71% vs 35%; 55% vs 16%).The higher OS was related with patients who were transplanted in remission, received grafts from related donors as well as having acute and chronic graft vs host disease. Conclusions: In the treatment of young patients who do not have comorbidities for intense conditioning regimens, show good performance status and are high risk; the initial use of standard myeloablative conditioning regimens is feasible. However, the lower number of RIC transplants and the variations between groups in terms of patient and donor characteristics might effect the results of this study. [Table: see text]