Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of chronic lymphocytic leukemia (CLL) meeting 1 of the following criteria:

- Previously untreated disease

- Progressive or relapsed CLL after treatment with nonpurine analog-containing
regimens as chlorambucil or bendamustine hydrochloride

- Meets 1 of the following staging criteria:

- Binet stage A disease with B symptoms requiring treatment

- Binet stage B disease requiring treatment, meeting ≥ 1 of the following
criteria:

- Rapid disease progression

- Enlarged lymph nodes and organs

- Severe B symptoms

- Binet stage C disease

- Must have comorbidities (i.e., CIRS score > 6)

- Must have restricted kidney function (i.e., creatinine clearance < 70mL/min)

- No transformation to aggressive non-Hodgkin's lymphoma (Richter's syndrome)

PATIENT CHARACTERISTICS:

- Life expectancy > 6 months

- Creatinine clearance > 30 mL/min

- No active second malignancy

- No active bacterial, viral, or fungal infection

- No conditions that would preclude substitution of iron

- No severe myocardial, coronary, or respiratory insufficiency

- No severe liver insufficiency

- No known hypersensitivity to darbepoetin alfa

- No cerebral dysfunction that would preclude participation in the required study
procedures

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- No concurrent participation in another clinical trial