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.