The effects of postinduction intensification treatment with cytarabine and daunorubicin in adult acute lymphocytic leukemia: a prospective randomized clinical trial by Cancer and Leukemia Group B.

Cancer and Leukemia Group B undertook a randomized trial of intensification treatment in adults aged 15 to 79 years with acute lymphocytic leukemia (ALL) in complete remission (CR). Daunorubicin (DNR), prednisone, vincristine (VCR), intrathecal (IT) methotrexate (MTX), and asparaginase produced 177 CRs in 277 patients. One hundred fifty-one patients were randomly assigned to receive treatment as follows: 74 received intensive cytarabine and DNR, and 77 received cycles of mercaptopurine (6-MP) and MTX, followed by 6MP, MTX, VCR, and prednisone for 3 years in all. One hundred twelve patients received CNS prophylaxis. Intensification produced major myelosuppression but did not improve remission duration (median, 21 months). Of the 151 patients with CRs who entered the intensification phase, 29% remain in continuous CR (43 to 117 months); in 19 patients, CRs have lasted for longer than 7 years. No relapses occurred after 60 months. Median survival from the time of randomization was 30 months. Those under 30 years of age responded more frequently, with longer CR and survival. While 53% of those aged 15 to 19 years remain in continuous CR, 92% of patients over 59 years have relapsed. The presence of a myeloid antigen on the leukemic cells was adversely prognostic for CR achievement and for survival. Pretreatment WBC and platelet levels independently affected CR duration and survival. Early M1 marrow development presaged longer remissions. CNS relapse occurred in 47 of 256 patients with normal CSF before treatment, in 29 before CNS prophylaxis. CNS disease occurred after CNS prophylaxis in 18 patients: 13 of 61 who had received standard premaintenance and five of 51 who received intensification. No advantage in CR duration or survival resulted from intensive treatment with DNR and cytarabine following induction of CR.