Azacitidine for relapse of acute myeloid leukemia or myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation, multicenter PALG analysis

Objectives Relapse of myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo‐HSCT) belongs to the major causes of treatment failure. Methods Retrospective multicenter analysis of patients diagnosed with AML or MDS who had hematological relapse after allo‐HSCT and were treated with azacitidine for this indication. Results Twenty‐three patients receiving azacitidine as the first treatment of relapse (Group_1) and 8 patients receiving azacitidine after other treatment of relapse (Group_2) were included. There were 68% males, median age at initiation of azacitidine was 53 years (15‐66). Median time to relapse was 3.5 months and 6.3 months in Group_1 and Group_2, respectively; median time from relapse to azacitidine 0.2 and 2.3 months. Azacitidine 75 mg/m2, days 1‐7, was administered in 78% and 75% of patients in Group_1 and Group_2, concomitant DLI in 48% and 50%. With median follow‐up of 4.7 and 13.6 months, the median overall survival was 5.9 and 9.5 months. 17% and 37.5% patients proceeded to salvage allo‐HSCT, with median OS of 11.6 months and not reached respectively. Conclusions Azacitidine treatment for hematological relapse is associated with poor outcome; nevertheless, a proportion of patients may benefit from it, including patients receiving subsequent salvage allo‐HSCT.