Maintenance therapy with Azacitidine for patients with myeloid malignancies after allogeneic hematopoietic stem cell transplantation

Disease relapse is a major cause of treatment failure after allogeneic haematopoietic stem cell transplantation (allo-HSCT) in patients with acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS). We retrospectively evaluated all patients (n = 145) with high-risk AML and MDS who underwent allo-HSCT between 2016 and 2022. Among them, 53 patients received maintenance therapy with azacitidine (AZA), and 10 of these patients received preemptive therapy. The rest of the 92 patients were in the control arm. The median follow-up time was 1215 days (103-3173 days). The median number of administered AZA cycles was 8. The 2-year relapse-free survival was 86.8% (46/53) in the AZA group compared with 76.1% (70/92) in the control group (P = 0.121). The 2-year overall survival in the AZA and control groups were 88.7% (47/53) and 82.6% (76/92), respectively (P = 0.326). Six patients (11.3%) in the AZA group experienced relapse, all of whom had a minimal residual disease (MRD)-positive status pre-HSCT. A total of 17 (32.1%) patients experienced grade 3-4 adverse events. In the preemptive therapy group, 70% (7/10) of the patients achieved complete remission after AZA treatment. AZA maintenance therapy following allo-HSCT is well tolerated and further follow-up and a larger group of patients will be necessary to confirm the potential to prevent relapse. The pre-transplant MRD status was identified as an important factor affecting the efficacy of AZA maintenance therapy.