Interferon Alfa and Imatinib Mesylate in Treating Patients With Chronic Myelogenous Leukemia

DISEASE CHARACTERISTICS: Diagnosis of chronic phase chronic myelogenous leukemia Cytogenetically confirmed Philadelphia chromosome-positive disease or other variant of t(9;22) No secondary chromosomal abnormalities No more than 10% blasts in bone marrow Newly diagnosed OR Received prior imatinib mesylate as a single agent for no more than the past 9 months without achieving a complete cytogenetic response No evidence of extramedullary involvement except nodes, liver, or spleen PATIENT CHARACTERISTICS: Age Any age Performance status ECOG 0-3 Life expectancy Not specified Hematopoietic Platelet count greater than 100,000/mm^3 Absolute neutrophil count greater than 1,500/mm^3 Hepatic Bilirubin no greater than 2 times upper limit of normal (ULN) SGOT no greater than 2 times ULN INR no greater than 1.5 times ULN* PTT no greater than 1.5 times ULN* NOTE: * Except patients on anticoagulants Renal Creatinine no greater than 2 times ULN Other Considered potentially reliable No history of noncompliance to medical regimens No other active malignancy requiring chemotherapy or radiotherapy Not pregnant or nursing Negative pregnancy test Fertile patients must use effective barrier-method contraception during and for at least 3 months after study PRIOR CONCURRENT THERAPY: Biologic therapy No prior interferon therapy No prior stem cell or bone marrow transplantation Chemotherapy No prior chemotherapy (except hydroxyurea and/or anagrelide to control counts) Endocrine therapy Not specified Radiotherapy Not specified Surgery At least 4 weeks since prior major surgery and recovered Other No concurrent grapefruit juice or grapefruit products No concurrent warfarin Concurrent low-molecular weight heparin allowed