DISEASE CHARACTERISTICS: Confirmed diagnosis of chronic myelogenous leukemia in accelerated phase At least 15% but less than 30% blasts in blood or bone marrow At least 30% blasts plus promyelocytes in the peripheral blood or bone marrow At least 20% peripheral basophils Thrombocyte count less than 100,000/mm3 (unrelated to therapy) Patients must have never been in blastic phase Ph chromosome positive OR Ph chromosome negative and Bcr/Abl positive