OUTLINE: This is a randomized, multicenter study. Patients are stratified by age (under 50 vs 50 and over) and duration of previous complete remission (CR) (0-6 vs 7-12 months). All patients receive induction chemotherapy comprised of cytarabine IV over 2 hours, mitoxantrone IV over a maximum of 20 minutes, and etoposide IV over 1-2 hours on days 1-6. On day 5 of induction, patients are randomized to one of two treatment arms: Arm I: Patients receive day 6 of induction chemotherapy. Patients then receive monoclonal antibody HuG1-M195 (MOAB HuM195) IV over 4 hours on days 6-9 or 7-10. Treatment with MOAB HuM195 repeats every 2 weeks for 2 courses (courses 1 and 2) in the absence of disease progression or unacceptable toxicity. During course 1, MOAB HuM195 begins 30 minutes to 24 hours postchemotherapy. Patients who do not achieve CR by day 70 of induction and show evidence of bone marrow progression (regimen failure (RF)) are taken off study. Patients without RF are assigned to one of two consolidation groups based on response: Group A (CR): Patients receive consolidation chemotherapy comprised of mitoxantrone IV over a maximum of 20 minutes on days 1 and 2, and cytarabine IV over 2 hours and etoposide IV over 1-2 hours on days 1-4. Patients with New York Heart Association class II heart disease preconsolidation receive no mitoxantrone during consolidation. Patients receive MOAB HuM195 IV over 4 hours on days 4-7 or 5-8. Treatment with MOAB HuM195 repeats every 2 weeks for 2 additional courses (courses 3 and 4). During course 3, MOAB HuM195 begins 30 minutes to 24 hours postchemotherapy. Group B (partial remission (PR), hematologic improvement (HI), or stable disease (SD)): Patients receive MOAB HuM195 as in group A but no consolidation chemotherapy. Patients without RF after treatment on group A or B receive maintenance MOAB HuM195 IV over 4 hours on days 1-4. Treatment repeats every month for 8 additional courses (courses 5-12). Arm II: Patients receive day 6 of induction chemotherapy. Patients receive no MOAB HuM195 during the entire study. Patients without RF at day 70 of induction are assigned to one of two consolidation groups based on response: Group C (CR): Patients receive consolidation chemotherapy as in group A. Group D (PR, HI, or SD): Patients receive no further treatment. Patients may be eligible to receive MOAB HuM195 on PDL Study 195-302. Patients are followed every 3 months for 1 year, and then every 6 months thereafter.