Imatinib Mesylate in Treating Patients With Myelofibrosis

DISEASE CHARACTERISTICS: Diagnosis of myelofibrosis with myeloid metaplasia (MMM), defined by all of the following: Leukoerythroblastic blood picture Fibrosis involving > 1/3 sectional area of bone marrow biopsy Splenomegaly (unless patient has undergone prior splenectomy) Philadelphia chromosome negative No myelodysplastic syndrome No systemic disorders associated with marrow fibrosis Red blood cell transfusion dependent, defined by 1 of the following: Patient has required ≥ 2 units of red blood cells every 4 weeks within the past 8 weeks Hemoglobin ≤ 8 g/dL on ≥ 3 occasions (≥ 2 weeks apart ) over the past 8 weeks No evidence of disease transformation to acute myelogenous leukemia, defined as > 20% blasts in bone marrow and/or peripheral blood PATIENT CHARACTERISTICS: Performance status ECOG 0-3 Life expectancy Not specified Hematopoietic Absolute neutrophil count > 1,000/mm^3 Platelet count > 50,000/mm^3 Hepatic Bilirubin ≤ 1.5 times upper limit of normal (ULN) AST or ALT ≤ 2 times ULN (unless due to extramedullary hematopoiesis in the liver) Renal Creatinine ≤ 1.5 times ULN Cardiovascular No New York Heart Association grade III-IV heart disease Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective barrier method contraception during and for 3 months after completion of study treatment No serious, uncontrolled medical condition No patients who are considered potentially unreliable or with a history of noncompliance to medical regimens PRIOR CONCURRENT THERAPY: Biologic therapy More than 2 weeks since prior interferon alfa Chemotherapy No concurrent chemotherapy except hydroxyurea to control elevated blood counts Endocrine therapy More than 4 weeks since prior corticosteroids, danazol, or other androgens for MMM Other More than 4 weeks since other prior treatment for MMM No other concurrent experimental drug therapy for MMM