Sargramostim in Treating Patients With Chronic Phase Chronic Myelogenous Leukemia Who Are Not in Complete Cytogenetic Remission Following Initial Treatment

DISEASE CHARACTERISTICS: Histologically confirmed chronic phase chronic myelogenous leukemia (CML) Presence of t(9;22)(q34;q11) with at least 20 cells examined in metaphase by cytogenetic examination of the bone marrow Complete hematologic remission during prior therapy* as seen on 2 separate blood count analyses, defined by the following: WBC no greater than 10,000/mm^3 AND platelet count no greater than 450,000/mm^3 Disappearance of all signs and symptoms of disease, including palpable splenomegaly Normal differential counts (i.e., absence of blasts, promyelocytes, myelocytes, and metamyelocytes) NOTE: *Continuation of therapy that led to complete hematologic remission is required during study participation Persistent cytogenetic disease despite 12 months of prior imatinib mesylate therapy, which may have included a trial dose-escalation OR intolerant of imatinib mesylate at a dose greater than 400 mg/day Not in complete cytogenetic remission within 30 days of study entry Persistent Philadelphia chromosome by bone marrow exam PATIENT CHARACTERISTICS: Age 18 and over Performance status ECOG 0-2 Life expectancy More than 6 months Hematopoietic See Disease Characteristics Hepatic Not specified Renal Not specified Other Not pregnant or nursing Fertile patients must use effective contraception No uncontrolled active infective No serious medical or psychiatric illness that would prevent giving informed consent or limit survival to less than 6 months No other malignancy not in remission except curatively treated basal cell skin cancer or carcinoma in situ of the cervix PRIOR CONCURRENT THERAPY: Biologic therapy Prior sargramostim (GM-CSF) allowed Prior interferon alfa for CML allowed No prior stem cell transplantation Concurrent interferon alfa* for CML allowed NOTE: *No dose increase during study participation Chemotherapy At least 4 weeks since prior chemotherapy Endocrine therapy Not specified Radiotherapy At least 4 weeks since prior radiotherapy No concurrent radiotherapy Surgery At least 4 weeks since prior surgery Other Prior imatinib mesylate for CML allowed No other concurrent medication for CML Concurrent imatinib mesylate* for CML allowed NOTE: *No dose increase during study participation