Imatinib Mesylate in Treating Patients With Chronic Myelogenous Leukemia

Inclusion Criteria: * Diagnosis of Philadelphia chromosome positive (Ph+) chronic phase chronic myelogenous leukemia (CML) * Stratum I (closed to accrual as of 12/05/03): * CML in first chronic phase with resistance to interferon alfa (IFN-A) therapy defined as one of the following: * WBC count at least 20,000/mm\^3 after at least 3 months of treatment with an IFN-A-containing regimen * Rising WBC count (at least 100% increase to a level of at least 20,000/mm\^3) by two samples at least two weeks apart while receiving treatment with an IFN-A-containing regimen * At least 66% Ph+ cells in bone marrow after 1 year of IFN-A therapy * At least 30% increase in Ph+ cells in bone marrow after IFN-A-induced cytogenetic response while continuing to receive IFN-A therapy * Intolerance to interferon therapy defined as more than two grade 2 toxic effects or any grade 3 toxic effect related to interferon therapy, except grade 3 fever, that is persistent beyond the first 28-day course of therapy and unresponsive to standard supportive care interventions * Stratum II (closed to accrual as of 7/29/05): CML recurring after stem cell transplantation or in second or subsequent chronic phase * No molecular relapse (only evidence is detection of bcr-abl rearrangement with normal bone marrow and blood morphology and normal standard cytogenetic analysis) * Stratum III (closed to accrual as of 7/29/05): Newly diagnosed CML in first chronic phase with no prior treatment except hydroxyurea * Stratum IV: Newly diagnosed CML in first chronic phase with no prior treatment except hydroxyurea * No accelerated or blast phase defined as one or more of the following: * WBC doubling time less than 5 days * Chloroma * Medullary fibrosis * More than 10% blasts in peripheral blood or bone marrow * More than 20% promyelocytes in peripheral blood or bone marrow * More than 20% basophils and eosinophils in peripheral blood * Performance status - ECOG 0-2 * At least 8 weeks * See Disease Characteristics * Shortening fraction ≥ 27% by echocardiogram OR ejection fraction ≥ 50% by radionuclide angiogram * Bilirubin no greater than 1.5 times normal * ALT less than 3.0 times normal * Albumin greater than 2 g/dL * Creatinine no greater than 1.5 times normal * Creatinine clearance or radioisotope glomerular filtration rate at least 70 mL/min * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No uncontrolled infection * No CNS toxicity greater than grade 2 * See Disease Characteristics * No prior immunotherapy (for patients in stratum III \[closed to accrual as of 7/29/05\] and stratum IV only) * At least 3 months since prior stem cell transplantation (SCT) (patients with allogeneic SCT must have no active graft-versus-host disease \[GVHD\] and have stable use of steroids) (for patients in stratum II only ) * At least 1 week since prior growth factors * At least 1 week since prior biologic therapy, including interferon alfa (for patients in stratum I \[closed to accrual as of 12/05/03\] and stratum II only) * Recovered from prior immunotherapy * No concurrent immunomodulating agents * See Disease Characteristics * No prior chemotherapy (for patients in stratum III \[closed to accrual as of 7/29/05\] and stratum IV only) * At least 6 weeks since prior busulfan or nitrosoureas * At least 7 days since prior hydroxyurea * At least 7 days since prior low-dose cytarabine (less than 30 mg/m\^2 every 12 to 24 hours) * At least 14 days since prior moderate-dose cytarabine (100-200 mg/m\^2 for 5 to 7 days) * At least 28 days since prior high-dose cytarabine (1-3 g/m\^2 every 12 to 24 hours for 6 to 12 doses) * At least 21 days since all other cytotoxic chemotherapy * Recovered from prior chemotherapy * No concurrent chemotherapy * No concurrent steroids other than for controlled GVHD in patients with prior allogeneic SCT * No prior radiotherapy (for patients in stratum III \[closed to accrual as of 7/29/05\] and stratum IV only) * At least 2 weeks since prior local palliative (small port) radiotherapy\* * At least 3 months since prior craniospinal radiotherapy or radiotherapy to 50% or more of pelvis\* * At least 6 weeks since prior substantial bone marrow radiotherapy\* * Recovered from prior radiotherapy * No prior imatinib mesylate * No concurrent enzyme-activating anticonvulsants * No concurrent warfarin * No concurrent naturopathic agents or herbal medicines * No other concurrent investigational agents * Concurrent low-molecular weight heparin allowed