DISEASE CHARACTERISTICS:

* Diagnosis of chronic lymphocytic leukemia (CLL) of any stage as defined by the following:

* Peripheral blood absolute lymphocyte count greater than 5,000/mm\^3 within 14 days prior to study
* Lymphocytes must be small to moderate size with no more than 55% prolymphocytes, atypical lymphocytes, or lymphoblasts morphologically
* Phenotypically characterized as B-CLL
* Must have one of the following characteristics indicating need for chemotherapy:

* Progressive marrow failure (hemoglobin less than 10 g/dL and/or platelet count less than 100,000/mm\^3)
* Progressive lymphocytosis with an increase of more than 50% over a 2 month period or anticipated doubling time of less than 6 months
* Massive (i.e., greater than 6 cm below left costal margin) or progressive splenomegaly
* Massive nodes or clusters (i.e., greater than 10 cm in longest diameter) or progressive adenopathy
* At least 10% weight loss within 6 months of study
* Extreme fatigue
* Fevers greater than 100.5 degrees F for 2 weeks without evidence of infection
* Night sweats without evidence of infection
* No autoimmune anemia or autoimmune thrombocytopenia

PATIENT CHARACTERISTICS:

Age:

* 18 and over

Performance status:

* ECOG 0-2

Life expectancy:

* Not specified

Hematopoietic:

* See Disease Characteristics

Hepatic:

* Bilirubin no greater than 2 mg/dL unless secondary to tumor

Renal:

* Creatinine no greater than 2.0 mg/dL
* Creatinine clearance at least 40 mL/min if creatinine is greater than 1.5 mg/dL

Other:

* No other prior or concurrent malignancy within the past 2 years except basal cell carcinoma of the skin or carcinoma in situ of the cervix
* No active infection requiring oral or intravenous antibiotics
* Not pregnant or nursing
* Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

* Not specified

Chemotherapy:

* No prior cytotoxic chemotherapy

Endocrine therapy:

* No prior steroid treatment for CLL

Radiotherapy:

* Not specified

Surgery:

* Not specified