- Arm I : Patients receive interferon alfa subcutaneously (SC) and GM-CSF SC once daily for 6 months. Patients who achieve a molecular complete remission (CR) (defined as BCR-ABL-negative disease confirmed by 2 PCR assays separated by 1 month) at the end of the 6-month period, discontinue study therapy and are monitored for disease recurrence by blood tests every 4 weeks. Patients who do not achieve a molecular CR (defined as BCR-ABL-positive disease) after completion of the initial 6 months of therapy, receive an additional 6 months of therapy as above. Patients who achieve BCR-ABL-negative disease during the additional 6 months of therapy, discontinue study therapy and are monitored for disease recurrence by blood tests every 4 weeks. Patients who remain BCR-ABL-positive by PCR after an additional 6 months of therapy, are eligible to cross over to arm II.