Comparative study of cytosine arabinoside therapy alone and combined with thioguanine, mercaptopurine, or daunorubicin in acute myelocytic leukemia.

Three hundred twenty-six patients with acute myelocytic leukemia were randomly and prospectively assigned to four therapeutic regimens: cytosine arabinoside either alone or in combination with daunorubicin, 6-mercaptopurine, or 6-thioguanine. The results in 231 qualified previously untreated patients were analyzed. The combination treatments produced a significantly greater frequency of complete or partial remission than single drug therapy. Treatment with cytosine arabinoside and thioguanine led to 48% age-adjusted complete and partial responses. The median sur survival from diagnosis of all 66 evaluable patients treated with these two drugs was 18 weeks, while the median survival for those who responded to this combination was 15 months.