5-azacytidine in refractory acute leukemia

11 patients (aged 23--75 years) with refractory acute leukemia were treated at the Maine Medical Center with 5-Azacytidine, 150 mg/m2/day, by continuous infusion for 5 days every 2 weeks. Prior therapy included anthracycline/cytosine arabinoside protocols. Of the 8 patients with refractory de novo acute myelogenous leukemia, 6 achieved remission at an overall response rate of 75% (3 complete remission and 3 partial remission). An average of 1.67 courses was necessary to achieve a response. Remissions were not seen in blastic chronic myelogenous leukemia nor in acute leukemia secondary to cytotoxic drugs. Toxicity included myelosuppression, moderate nausea and vomiting, abnormal liver function tests, and neuromuscular symptoms. 5-Azacytidine by continuous infusion has significant activity in refractory acute myelogenous leukemia and should be considered for inclusion in primary remission induction therapy.