Azacitidine for Relapse After Allogeneic Stem Cell Transplantation-Single-Center Study.

BACKGROUND: Relapse is the leading cause of treatment failure for myeloid malignancies treated with allogeneic hematopoietic stem cell transplantation. Treatment options are very limited and use of azacitidine is one of the available options.

METHODS: This was a retrospective, single-institution study. Of 28 evaluated patients, 18 were males, and the median age was 60 years (range, 15-78). There were 15 patients with acute myeloid leukemia, 8 with myelodysplastic syndrome, 4 with chronic myelomonocytic leukemia, and 1 with primary myelofibrosis. Ten patients received azacitidine for overt relapse, 14 received it as a preemptive therapy, and 4 others received it as maintenance treatment after allo-hematopoietic cell transplant (HSCT). Eleven patients received a donor lymphocyte infusion (DLI).

RESULTS: The patients received median 5 (1-9) cycles of azacitidine in preemptive and maintenance therapy and median 2.5 (1-9) cycles in patients with relapse. Thirty-nine percent of patients received DLIs. Median overall survival was 6.1 months (95% CI, 0.7-13) for relapse therapy vs 21.2 months (95% CI, 8.4-inf) for preemptive therapy. Among patients treated for relapse, 30% achieved temporary disease control and underwent the second allo-HSCT. A complete, cytogenetic remission was achieved in 50% of patients and stable minimal residual disease in 14% of patients in a group with preemptive therapy. Toxicity was considerable; neutropenia (71%), anemia (14%), thrombocytopenia (36%), and serious infections (36%) were observed in the preemptive setting.

CONCLUSIONS: These data support the notion that azacitidine is best used as a preemptive therapy against relapse for patients after allo-HSCT performed for myeloid malignancy. Applying azacitidine as therapy for ongoing relapse after allo-HSCT may lead to stable disease and allow for better performance of the second allo-HSCT.