OBJECTIVE To assess the efficacy and toxicity of a new treatment program of intensified and shortened cyclical chemotherapy (protocol 8707) in adults with acute lymphoblastic leukemia (ALL). METHODS Previously untreated adults < or = 60 years old with ALL were treated with a four-agent induction chemotherapy regimen. This was followed by cyclical postremission therapy with high-dose cytarabine/etoposide; high-dose methotrexate/6-mercaptopurine; and daunorubicin, vincristine, prednisone, and asparaginase. Maintenance chemotherapy with oral methotrexate and 6-mercaptopurine was continued for 30 months. CNS prophylaxis was given with intrathecal methotrexate in addition to the systemic chemotherapy indicated above. RESULTS Seventy-eight of 84 patients (93%) achieved complete remission. With a median follow-up of 5.6 years, 5-year event-free survival (EFS) of all remission patients is 52%. Patients with high-risk features including adverse cytogenetics, failure to achieve remission with the first cycle of chemotherapy, and B-precursor disease with WBC counts more than 100,000/microL all relapsed unless taken off study for transplantation. For patients without these high-risk features, 5-year EFS was 60%. Compared with our previous treatment regimen, results appear to be improved for patients with standard-risk B-precursor disease (5-year EFS, 66% v 34%; P =.01). CONCLUSIONS Intensified and shortened chemotherapy may improve the outcome for patients with ALL with B-precursor disease lacking high-risk features. Further trials of this regimen are warranted.