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