Inclusion Criteria

DISEASE CHARACTERISTICS:

- Confirmed diagnosis of B-cell chronic lymphocytic leukemia (CLL)

- Previously untreated

- Rai stage I, II, III, or IV

- Requiring systemic therapy

- Persistent lymphocytosis of greater than 5,000/mm^3

- Morphologically mature lymphocytes

- Monoclonal B-cell population

- CD19/CD5/CD23 positive with kappa or lambda light chain restriction by
immunophenotyping

- No other lymphoproliferative disorders including prolymphocytic leukemia, mantle cell
lymphoma, progression to aggressive B-cell lymphoma, or Richter's syndrome

- No clinical autoimmune hematologic complication of CLL including Coomb's-positive
hemolytic anemia or immune thrombocytopenia

- Positive Coomb's test allowed if no clinical hemolysis

PATIENT CHARACTERISTICS:

Age

- 16 and over

Performance status

- ECOG 0-2

Life expectancy

- At least 6 months

Hematopoietic

- See Disease Characteristics

Hepatic

- Bilirubin no greater than 2 times upper limit of normal (ULN)

- AST and/or ALT no greater than 2 times ULN

Renal

- Creatinine no greater than 2 times ULN

Other

- Accessible for treatment and follow-up

- No known HIV infection

- No active bacterial, viral, or fungal infection requiring systemic antibiotics

- No conditions requiring corticosteroid therapy

- No history of other malignancies except for the following:

- Adequately treated nonmelanoma skin cancer

- Curatively treated carcinoma in situ of the cervix

- Other solid tumors curatively treated with no evidence of disease within the
past 5 years

- No other major medical illness that would preclude study

- No known hypersensitivity to fludarabine or its components

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during and for at least 6 months
after study

PRIOR CONCURRENT THERAPY:

Biologic therapy

- No concurrent immunotherapy including monoclonal antibody therapy

- No concurrent autologous or allogeneic stem cell or bone marrow transplantation

Chemotherapy

- No other concurrent cytotoxic drugs

Endocrine therapy

- No concurrent corticosteroids except inhaled or topical corticosteroids

- No concurrent corticosteroids for nausea prophylaxis

Radiotherapy

- No prior radiotherapy affecting more than 25% of bone marrow and/or involving the
pelvic area

- No concurrent radiotherapy

Surgery

- Not specified

Other

- At least 4 weeks since prior investigational agents

- No other concurrent investigational agents