Chemotherapy in Treating Patients With Previously Untreated Chronic Lymphocytic Leukemia

DISEASE CHARACTERISTICS: Diagnosis of B-cell chronic lymphocytic leukemia (CLL) manifested by all of the following: Threshold peripheral lymphocyte count greater than 5000/mm3 Small to moderate peripheral lymphocytes with no greater than 55% prolymphocytes Peripheral lymphocyte count less than 15,000/mm3 At least 30% lymphoid cells in bone marrow Monoclonality of B lymphocytes Active disease by at least one of the following criteria: Weight loss of at least 10% within the past 6 months or prolonged fever or night sweats without evidence of infection Progressive marrow failure (stage III or IV disease) manifested by Hemoglobin less than 11 g/dL (anemia) AND/OR Platelet count less than 100,000/mm3 (thrombocytopenia) Autoimmune anemia and/or thrombocytopenia minimally responsive to corticosteroid therapy Massive or progressive splenomegaly Massive or progressive lymphadenopathy Progressive lymphocytosis (not due to the effects of corticosteroids) Marked hypogammaglobulinemia or development of monoclonal protein in the absence of any of the above criteria is not sufficient for eligibility 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) SGOT no greater than 1.5 times ULN (unless due to hemolysis or CLL) Renal: Creatinine no greater than 1.5 times ULN Cardiovascular: No New York Heart Association class III or IV heart disease No myocardial infarction in the past month Other: No uncontrolled infection No active infection with HIV (AIDS) No other malignancy within past 2 years except nonmelanomatous skin cancer or carcinoma in situ of the cervix Not pregnant or nursing Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: Prior interferon allowed Chemotherapy: No prior cytotoxic chemotherapy Endocrine therapy: See Disease Characteristics Prior corticosteroids, somatostatin analogues, and tamoxifen allowed Radiotherapy: At least 4 weeks since prior radiotherapy Surgery: At least 4 weeks since prior major surgery