OBJECTIVES: I. Determine the safety of STI571 in patients with accelerated phase Philadelphia chromosome positive (or chromosome negative and Bcr/Abl positive) chronic myelogenous leukemia. II. Determine the rate of hematological response to this treatment in these patients. III. Determine the improvements in symptomatic parameters with this treatment in these patients. IV. Determine the cytogenetic response to this treatment in these patients. V. Determine the time to treatment failure in these patients after receiving this treatment.