DISEASE CHARACTERISTICS:

• Diagnosis of Philadelphia (Ph) chromosome-positive chronic myelogenous leukemia (CML) in chronic or accelerated phase, defined as having any of the following:

  • Peripheral blood (PB) or bone marrow (BM) blasts at least 10% but less than 30%
  • PB or BM blasts and promyelocytes at least 20%
  • PB or BM basophils at least 20%
  • Progressive splenomegaly (at least 10 cm confirmed twice at least 4 weeks apart or 50% increase in splenomegaly over 4 weeks)
  • Clonal evolution defined as the presence of additional cytogenetic abnormalities other than the Ph chromosome
  • Thrombocytopenia (platelet count less than 100,000/mm^3) unrelated to therapy
  • Hemoglobin less than 7 g/dL unrelated to therapy or bleeding
• Failed prior treatment with imatinib mesylate or intolerant, unable, or unwilling to receive it
• Ineligible for higher-priority or higher-efficacy regimens or protocols
• No blastic phase CML

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Life expectancy:

• At least 18 weeks

Hematopoietic:

• See Disease Characteristics

Hepatic:

• Bilirubin no greater than 1.5 mg/dL

Renal:

• Creatinine no greater than 1.5 mg/dL OR
• Creatinine clearance greater than 60 mL/min

Other:

• No other concurrent illness that would preclude study entry
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No more than 2 prior cytotoxic regimens in addition to imatinib mesylate and/or hydroxyurea
• At least 4 weeks since prior chemotherapy and recovered
• Concurrent hydroxyurea and/or anagrelide allowed during first 2 courses

Endocrine therapy:

• Not specified

Radiotherapy:

• At least 4 weeks since prior radiotherapy and recovered

Surgery:

• Not specified

Other:

• See Disease Characteristics
• See Chemotherapy
• At least 24 hours since prior imatinib mesylate
• No other concurrent investigational agents