RATIONALE: Imatinib mesylate may stop the growth of cancer cells by blocking the enzymes necessary for cancer cell growth. Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Giving imatinib mesylate together with decitabine may kill more cancer cells.

PURPOSE: This phase II trial is studying how well giving imatinib mesylate together with decitabine works in treating patients with accelerated or blast phase chronic myelogenous leukemia.

OBJECTIVES:

• Determine the duration of response and response rate in patients with accelerated or blastic phase chronic myelogenous leukemia treated with imatinib mesylate and decitabine.
• Determine the survival rate of patients treated with this regimen.
• Determine the toxicity of this regimen in these patients.
• Determine the effects of this regimen on gene methylation in the leukemic cells of these patients.

OUTLINE: Patients are stratified according to prior exposure to imatinib mesylate (yes vs no).

Patients receive oral imatinib mesylate daily and decitabine IV over 1 hour daily, 5 days per week, for 2 consecutive weeks. Courses repeat every 4-6 weeks in the absence of disease progression or unacceptable toxicity.

PROJECTED ACCRUAL: A total of 20-80 patients (10-40 per stratum) will be accrued for this study within 20 months.

• Drug: decitabine
• Drug: imatinib mesylate

DISEASE CHARACTERISTICS:

• Histologically confirmed chronic myelogenous leukemia

  • Philadelphia chromosome positive by cytogenetics OR fluorescent in situ hybridization
  • Accelerated or non-lymphoid blastic phase

PATIENT CHARACTERISTICS:

Age

• Any age

Performance status

• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• Not specified

Hepatic

• Bilirubin no greater than 2 times upper limit of normal (ULN)
• AST no greater than 2 times ULN

Renal

• Creatinine less than 2.0 mg/dL

Cardiovascular

• Normal cardiac function
• No New York Heart Association class III or IV heart disease

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• No prior decitabine
• At least 2 weeks since other prior chemotherapy (unless there is evidence of rapidly progressive disease) and recovered
• Concurrent hydroxyurea allowed during the first 2 courses of study therapy in patients with rapidly progressing disease

Endocrine therapy

• Not specified

Radiotherapy

• Not specified

Surgery

• Not specified

Other

• Prior imatinib mesylate allowed

  • Patients who received at least 4 weeks of prior imatinib mesylate must have failed therapy, as evidenced by resistance after 8 weeks or disease progression
• No concurrent grapefruit or grapefruit juice