Combination chemotherapy for acute nonlymphoblastic leukemia in adults.

Between January 1973 and February 1975, 77 adults with acute nonlymphoblastic leukemia were treated with a combination of daunorubicin, cytosine arabinoside, 6-thioguanine, prednisone, and vincristine in university-affiliated and private institutions. After 31 patients were treated (regimen 1) the doses of all drugs were significantly increased (regimen 2). Regimes 1 and 2 yielded CR rates of 59% (17 of 29 patients) and 70% (32 of 46 patients) respectively. With regimens 2 the mean number of courses and the median number of days to CR decreased from 3 to 1.4 and from 46 to 29 respectively. Failure to achieve CR was due to persistent leukemia during regimen 1 and fatal infections during regimen 2. With regimen 2 ten of 20 patients (50%) greater than 50 years had CR compared to 22 of 26 patients (85%) less than 50 years. CR rates were similar in community and university institutions.