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