DISEASE CHARACTERISTICS: Acute myelogenous leukemia (M0-M7) and acute lymphoblastic leukemia (L1-L2) Refractory or in first or subsequent relapse Circulating blasts present OR Greater than 5% blasts in bone marrow Acute myelogenous leukemia secondary to myelodysplastic syndrome or cytotoxic therapy Untreated OR Maximum of 2 intensive induction regimens Chronic myelogenous leukemia in blastic or lymphoid crisis Untreated OR Maximum of 2 intensive induction regimens No CNS leukemia