Azacitidine as salvage therapy for relapsed acute myeloid leukemia/myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation

Objective There are no established salvage therapies for relapsed myeloid malignancies after allogeneic hematopoietic stem cell transplantation (allo‐HSCT). Azacitidine (AZA) has been reported as a promising treatment in such cases. Methods We conducted a retrospective analysis of patients at our institution who received AZA for relapse after allo‐HSCT between 2014 and 2015. Results Twenty‐two patients received AZA as salvage therapy; 19 had acute myeloid leukemia and 3 had myelodysplastic syndrome. The median number of AZA cycles was 2 (range, 1‐12). Seventy‐seven percent of patients received AZA at a dose of 75 mg/m2 for either 5 or 7 days. The median interval between each AZA administration was 32 days (20‐63 days). Donor lymphocyte infusion (DLI) was administered in 5 patients. The median follow‐up period after AZA therapy was 360 days (range, 63‐805). The overall response rate was 15% in patients with non‐hematological CR (Non‐HCR) or hematological relapse (H‐Rel) and 56% in patients with molecular relapse (M‐Rel). The 1‐year overall survival (OS) rates in patients with Non‐HCR/H‐Rel and M‐Rel were 37.3% and 74.1%, respectively (P = 0.30). Patients who received DLI had favorable OS, and those with early H‐Rel had poor OS. Grade 3‐4 infection occurred in 12 patients. Discussion Our study suggests that AZA ± DLI is a tolerable and promising treatment in M‐Rel patients. The efficacy of AZA in H‐Rel patients is limited.