DISEASE CHARACTERISTICS: Documented acute myelogenous leukemia (AML) including secondary AML and biphenotypic leukemia Secondary AML may be either chemotherapy induced or evolving from a myelodysplastic syndrome Bone marrow evidence of AML must include the following: Cellularity of 20% or greater Minimum of 20% leukemic cells Signs of bone marrow failure such as: Anemia (hemoglobin less than 12.0 g/dL) Granulocytopenia (granulocyte count less than 1,500/mm3) Thrombocytopenia (platelet count less than 100,000/mm3) Must not be any of the following: Acute lymphoblastic leukemia Blastic phase of chronic myelogenous leukemia Acute promyelocytic leukemia (M3) Prior induction therapy using any conventional induction chemotherapy regimen required In first or second relapse after successful induction therapy OR Failed 1 attempt at reinduction relapse OR Refractory to at least 1 prior induction therapy No prior induction therapy allowed in secondary AML or in newly diagnosed AML in patients at least 65 years old

PATIENT CHARACTERISTICS: Age: 16 and over Performance status: ECOG 0-2 Life expectancy: At least 6 weeks Hematopoietic: See Disease Characteristics No evidence of being platelet transfusion refractory WBC no greater than 20,000/mm3 (leukapheresis, hydroxyurea, or both allowed) Hepatic: Bilirubin no greater than 2.0 mg/dL unless leukemic infiltration to liver SGOT or SGPT less than 2 times upper limit of normal Renal: Creatinine no greater than 2.0 mg/dL Cardiovascular: No evidence of symptomatic coronary atherosclerotic heart disease Other: Not pregnant Negative pregnancy test Fertile patients must use effective contraception No active infection and afebrile Afebrile, stable, and completing antibiotics allowed Febrile not from infection but from blood products allowed

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent bone marrow transplantation Chemotherapy: See Disease Characteristics At least 3 weeks since prior chemotherapy No other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: No concurrent radiotherapy Surgery: Not specified Other: No other concurrent antileukemic agents