Objective  To investigate the efficacy and safety of maintenance therapy with azacitidine for acute myeloid leukemia (AML) patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

  Methods  The clinical data of 30 AML patients who received maintenance therapy with azacitidine (after allo-HSCT in The Second Affiliated Hospital of Air Force Military Medical University from November 2018 to August 2021) were retrospectively analyzed. The minimal residual disease (MRD) status of the patients after allo-HSCT and the incidence of graft-versus-host disease (GVHD) were monitored. The overall survival (OS) rate, disease-free survival (DFS) rate, and the cumulative incidence of relapse were estimated via Kaplan-Meier methodology and the safety of the treatment protocol was analyzed.

  Results  83.33% (25/30) patients received at least four cycles of azacitidine maintenance therapy, while 36.67% (11/30) patients received all six cycles of azacitidine maintenance therapy. The MRD status of 10 patients was positive before maintenance therapy, and the MRD status of 9 patients turned negative after maintenance therapy. The overall negative conversion rate was 90%. Following up until November 30, 2021, the median OS time of the 30 patients was (33.7±1.8) months, the three-year OS rate was (83.2±9.9)%, and the three-year DFS rate was (81.3±9.4)%. Until the end of follow-up time, four patients relapsed, and the three-year cumulative incidence of relapse was (18.7±9.4)%. The incidence of grade 3/4 hematological toxicities was 23.33% (7/30). Chronic GVHD (cGVHD) of skin was alleviated in two of the patients, and cGVHD of the liver was aggravated in one of the patients. No new onset of GVHD occurred in any of the patients.

  Conclusions  Maintenance therapy with azacitidine for AML patients after allo-HSCT could reduce the relapse rate and improve the survival of patients. The therapy also has low hematologic toxicity and exhibits no increases in the incidence of GVHD.