DISEASE CHARACTERISTICS:

• Cytogenetically confirmed chronic phase chronic myelogenous leukemia (CML)

  • Less than 15% blasts in peripheral blood or bone marrow
  • Less than 30% blasts and promyelocytes in peripheral blood or bone marrow
  • Less than 20% basophils in blood or bone marrow
  • Platelet count at least 100,000/mm^3
• Philadelphia chromosome positive
• No more than 6 months since initial diagnosis
• No presence of leukemia beyond the bone marrow, blood, liver, or spleen (i.e., chloroma)
• Refused allogeneic stem cell transplantation as first-line therapy

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• See Disease Characteristics

Hepatic:

• Bilirubin no greater than 1.5 times upper limit of normal (ULN)
• AST or ALT no greater than 2 times ULN

Renal:

• Creatinine no greater than 1.5 times ULN

Cardiovascular:

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

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective barrier contraception during and for at least 3 months after study participation
• No other serious uncontrolled medical condition
• No history of noncompliance to medical regimens or potential unreliability

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• See Disease Characteristics
• No prior biologic therapy for CML

Chemotherapy:

• No prior chemotherapy for CML except hydroxyurea
• Concurrent hydroxyurea to control blood counts during first 3 months of treatment allowed
• No other concurrent chemotherapy

Endocrine therapy:

• No prior endocrine therapy for CML

Radiotherapy:

• No prior radiotherapy for CML

Surgery:

• Not specified

Other:

• More than 28 days since prior investigational anticancer agents
• Prior anagrelide hydrochloride for CML allowed
• Concurrent anagrelide hydrochloride to control blood counts during first 3 months of treatment allowed
• No concurrent grapefruit juice or grapefruit