Maintenance therapy with low‐dose azacitidine after allogeneic hematopoietic stem cell transplantation for recurrent acute myelogenous leukemia or myelodysplastic syndrome

BACKGROUND: Recurrence is a major cause of treatment failure after allogeneic transplantation for acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS), and treatment options are very limited. Azacitidine is a DNA methyltransferase inhibitor with activity in myeloid disease. The authors hypothesized that low‐dose azacitidine administered after transplant would reduce recurrence rates, and conducted a study to determine a safe dose/schedule combination. METHODS: Forty‐five high‐risk patients were treated. Median age was 60 years; median number of comorbidities was 3; 67% were not in remission. By using a Bayesian adaptive method to determine the best dose/schedule combination based on time to toxicity, the authors investigated combinations of 5 daily azacitidine doses, 8, 16, 24, 32, and 40 mg/m 2 , and 4 schedules: 1, 2, 3, or 4 cycles, each with 5 days of drug and 25 days of rest. Cycle 1 started on Day +40. RESULTS: Reversible thrombocytopenia was the dose‐limiting toxicity. The optimal combination was 32 mg/m 2 given for 4 cycles. Median follow‐up was 20.5 months. One‐year event‐free and overall survival were 58% and 77%, justifying further studies to estimate long‐term clinical benefit. No dose significantly affected DNA global methylation. CONCLUSIONS: Azacitidine at 32 mg/m 2 given for 5 days is safe and can be administered after allogeneic transplant for at least 4 cycles to heavily pretreated AML/MDS patients. The trial also suggested that this treatment may prolong event‐free and overall survival, and that more cycles may be associated with greater benefit. Cancer 2010. © 2010 American Cancer Society.