Low-dose azacitidine after allogeneic stem cell transplantation for acute leukemia

Background: The authors hypothesized that low doses of the hypomethylating agent 5-azacitidine may maximize the graft-versus-leukemia effect and may be tolerated well after allogeneic transplantation (HSCT). METHODS: The drug was given to 17 patients with acute leukemia as salvage for disease recurrence after HSCT (n=9 patients) or as maintenance therapy (n = 8 patients). 5-Azacitidine was given subcutaneously daily for 5 days and was repeated every 4 weeks at doses of 16 mg/m ²(n = 4 patients), 24 mg/m ²(n = 9 patients), and 40 mg/m ²(n = 4 patients). A median of 8 cycles was delivered. The median follow-up was 16 months and 11 months after HSCT and 5-azacitidine treatment, respectively. RESULTS: Five of 9 patients with recurrent disease responded. Four of 13 responding patients developed disease recurrence while they were receiving 5-azacitidine after a median of 10 months. The actuarial 1-year eventfree and overall survival rates were 55% and 90%, respectively. There were no extramedullary toxicities, and no graft-versus-host disease exacerbation was observed. CONCLUSIONS: Low-dose 5-azacitidine may induce durable remissions for patients who develop disease recurrence after HSCT. Further follow-up and a larger group of patients will be necessary to confirm these observations.