PRIOR CONCURRENT THERAPY: Biologic therapy: See Disease Characteristics At least 30 days since prior experimental biologic therapy (e.g., interleukin-2) No concurrent biologic therapy, including bone marrow transplantation Chemotherapy: See Disease Characteristics For first relapse AML with recent or prior chemotherapy: Prior hydroxyurea given as a short course (up to 48 hours) allowed, if needed, to reduce the peripheral leukocyte count Hydroxyurea must be discontinued prior to study For refractory AML with recent or prior chemotherapy: Greater than 2 weeks since prior chemotherapy except hydroxyurea given as above No other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: No concurrent radiotherapy Surgery: Not specified Other: No other concurrent experimental therapy Concurrent therapy for other preexisting diseases allowed