RATIONALE: Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Combining biological therapy with chemotherapy may kill more cancer cells.

PURPOSE: Phase II trial to study the effectiveness of chemotherapy with cytarabine and homoharringtonine and biological therapy with interferon alfa in treating patients with chronic phase chronic myelogenous leukemia.

OBJECTIVES: I. Determine the effectiveness of low dose cytarabine, homoharringtonine, and interferon alfa in stimulating a complete cytogenic response in patients with Philadelphia chromosome positive early chronic phase chronic myelogenous leukemia. II. Evaluate the duration of the cytogenic response in these patients after this treatment. III. Determine differential success rates and analyze results by prognostic subsets (e.g., risk group, splenomegaly, thrombocytosis, age, etc.) in this patient population.

OUTLINE: Patients receive debulking therapy consisting of hydroxyurea until blood count is at proper level. Patients then receive interferon alfa and cytarabine daily by subcutaneous injection. Homoharringtonine is administered by continuous infusion on days 1-5. Treatment continues for 5-7 years in the absence of unacceptable toxicity or disease progression (accelerated or blastic phase CML). If complete remission is achieved, peripheral blood stem cells are collected. Patients are followed every 3 months for the first year and every 6 months thereafter.

PROJECTED ACCRUAL: A total of 100 patients will be accrued for this study within 3 years.

DISEASE CHARACTERISTICS: Cytologically confirmed early chronic phase chronic myelogenous leukemia (CML) Diagnosed within 12 months Philadelphia chromosome positive OR bcr positive No late chronic phase, accelerated phase, or blastic phase CML

PATIENT CHARACTERISTICS: Age: 12 and over Performance status: Zubrod 0-2 Life expectancy: Not specified Hematopoietic: Not specified Hepatic: Bilirubin less than 2 mg/dL Renal: Creatinine less than 2 mg/dL Cardiovascular: No severe heart disease Other: No psychoses Not pregnant or nursing Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: Less than 1 month of prior interferon alfa Chemotherapy: Less than 1 month of prior cytarabine Prior hydroxyurea allowed Endocrine therapy: Not specified Radiotherapy: Not specified Surgery: Not specified