OBJECTIVES: I. Evaluate the antileukemic effects of humanized anti-CD33 monoclonal antibody M195 (HuM195) against minimal residual disease in patients with acute promyelocytic leukemia (APL) by using a reverse transcription-polymerase chain reaction for the mutated retinoic acid receptor-alpha to detect changes in minimal residual disease. II. Assess the disease free and overall survival of patients with APL receiving HuM195 for minimal residual disease. III. Evaluate the safety and toxicity of HuM195 in these patients. IV. Evaluate whether HuM195 elicits a human anti-human antibody response, including anti-idiotype antibody responses, in patients with APL.

OUTLINE: Patients continue retinoid therapy until 30 days after documentation of clinical complete remission. Patients begin treatment within 10 days of documentation of clinical complete remission, or after RT-PCR-confirmed molecular relapse, or 3-6 weeks after chemotherapy. Patients receive HuM195 IV over 60 minutes twice a week for 6 doses. Patients with unacceptable toxicity, in first complete remission, or ineligible for bone marrow transplant (BMT) proceed to the next regimen. Patients receive idarubicin IV over 15 minutes on days 1-3 and cytarabine IV continuously over days 1-5. Patients then receive 2 more courses, given at 4-6 week intervals, consisting of idarubicin IV over 15 minutes on days 1-2 and cytarabine IV continuously on days 1-4. Patients begin maintenance therapy after toxicity resolves or 1 week after the last dose of HuM195. This consists of HuM195 IV over 60 minutes for 2 doses (72-96 hours apart). Treatment repeats once a month for 6 courses. Patients who have an initial molecular response but are positive on the RT-PCR assay, or who achieve complete remission following clinical relapse of disease during treatment are eligible for retreatment. Patients are followed every 3 months.

PROJECTED ACCRUAL: A total of 14-40 patients will be accrued for this study over 2-3 years.