Homoharringtonine and Interferon Alfa in Treating Patients With Chronic Myelogenous Leukemia

DISEASE CHARACTERISTICS: Chronic myelogenous leukemia (CML) in chronic phase Clonal evolution (i.e., the presence of clones other than the Ph chromosome) allowed Ph chromosome variants or complex Ph chromosome translocations are not considered disease acceleration Ineligible for known therapy of higher efficacy or priority Allogeneic bone marrow transplantation should be considered priority therapy for CML patients with a matched related donor No blastic phase CML (30% or more blasts in peripheral blood or bone marrow) No accelerated phase CML, defined as any of the following: 15% or more peripheral or marrow blasts or 30% or more blasts and promyelocytes 20% or more peripheral or marrow basophils Thrombocytopenia (platelets less than 100,000) unrelated to therapy Documented extramedullary disease outside of liver or spleen PATIENT CHARACTERISTICS: Age: 15 and over Performance status: Zubrod 0-2 Life expectancy: Sufficient to fully evaluate the effects of 2 courses of therapy Bilirubin no greater than 2.0 mg/dL SGOT less than 300 Creatinine less than 2.0 mg/dL OR creatinine clearance at least 60 mL/min No severe heart disease (class III/IV) No pregnant or nursing women Effective contraception required of fertile women PRIOR CONCURRENT THERAPY: No prior interferon alpha At least 2 weeks since antileukemic therapy, with recovery required Patients who received hydroxyurea within the past 2 weeks and have WBC greater than 50,000 may enter protocol after discussion with the primary investigator