5-azacytidine in acute leukemia.

101 patients with acute leukemia in relapse were treated with 5-azacytidine according to three schedules: Regimen A--300 mg/m2(day divided intravenously at 8 hour intervals for 5 days; Regimen B--750 mg/m2 as a single iv pulse dose administered at 2 to 3 weeks intervals; and Regimen C--300 mg/m2/day by continuous infusion daily for 5 days. Twelve patients achieved a complete remission (CR) and six achieved a partial remission (PR) for an overall 18% response rate. Of 78 patients receiving an adequate trial the response rate was 23%. An average of 1.5 courses and a median of 5 weeks were necessary to achieve a response. The median duration of CR patients was 21 weeks and for PR patients it was 5 weeks. Response rates were 24% for Regimen A, 0 for Regimen B, and 1 of 8 for Regimen C. The CR rate for AML and AMML was 13%. Two of eight AMoL patients achieved a CR. Only 2 of 23 ALL patients responded, one of whom achieved a CR. Toxicity included moderate to severe nausea and vomiting, diarrhea, stomatitis, skin rash, and prolonged myelosuppression. 5-azacytidine has significant activity in the acute nonlymphoblastic leukemias.