DISEASE CHARACTERISTICS: Cytogenetically or molecularly proven chronic phase chronic myeloid leukemia (CML) that is Philadelphia chromosome positive OR Philadelphia chromosome negative with evidence of the BCR-ABL rearrangement or evidence of the P120 protein On interferon alfa therapy less than 6 months In complete hematologic response, defined as: WBC less than 10,000/mm3 Platelet count less than 450,000/mm3 Less than 5% circulating blasts No signs and symptoms of disease, including progressive splenomegaly