Comparison between different reduced intensity conditioning regimens in AML/MDS patients in a Latin American center of adult stem cell transplantation

<b>Background:</b> Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for several hematological diseases. Prospective and retrospective studies have associated myeloablative conditioning regimens with increased non-relapse mortality and less intense regimens with disease relapse, leading to similar overall survival rates.<b>Objectives:</b> Analyze the experience with the different RIC schemes in patients transplanted for AML/MDS in our program.<b>Methods:</b> We retrospectively analyzed our program's reduced-intensity conditioning regimens (RIC) between 2012 and 2022 in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS).<b>Results:</b> During this period, 450 allogeneic stem cell transplantations were performed, of which 52 patients were treated with RIC for AML, mostly in men. The 3-year overall survival/progression-free survival rates were 52/53%, 51/57%, and 57/55% in the fludarabine-reduced intensity with total-body irradiation, Melphalan, and Busulfan, respectively (<i>p</i> = 0.89). The composite incidences of aGVHD III-IV, cGVHD, and admission to the critical patient unit were 21%, 25%, and 30%, respectively, without statistically significant differences according to the type of conditioning, but with a trend of greater ICU admission in patients who used melphalan-based conditioning.<b>Conclusion:</b> Our study found no differences in overall survival, progression-free survival, and complications between the most commonly used reduced-intensity conditioning regimens.