Pentostatin, Cyclophosphamide, and Rituximab in Treating Patients With Previously Untreated Chronic Lymphocytic Leukemia

DISEASE CHARACTERISTICS:

Diagnosis of chronic lymphocytic leukemia (CLL), as evidenced by an absolute lymphocytosis in the blood of at least 5,000 lymphocytes per microliter OR bone marrow lymphocytosis ≥ 30% of all nucleated cells

Previously untreated disease

Meets 1 of the following risk criteria as defined by the three-stage Rai system

Intermediate-risk disease

Must meet the criteria for active disease as defined by the NCI Working Group guidelines including the following:

Weight loss
Fatigue
Fevers
Evidence of progressive marrow failure
Splenomegaly
Progressive lymphadenopathy
Progressive lymphocytosis with a rapid doubling time
High-risk disease
Malignant lymphocytes must demonstrate B-cells via immunophenotypic or immunohistochemical analysis
Patients with small lymphocytic lymphoma (CLL type) are eligible

PATIENT CHARACTERISTICS:

Inclusion criteria:

Karnofsky performance status 60-100%
Total bilirubin ≤ 2.0 mg/dL (patients with Gilbert disease or autoimmune hemolytic anemia should have an evaluation for other causes of hyperbilirubinemia, but if none are found they may be enrolled regardless of serum bilirubin)
Total creatinine ≤ 2.0 mg/dL OR creatinine clearance > 50 mL/min
Not pregnant or nursing
Fertile patients must use effective contraception
Patients with autoimmune hemolytic anemia or autoimmune thrombocytopenia are eligible for treatment on this protocol regardless of disease stage

Exclusion criteria:

Significant active infections

Ongoing hepatitis B infection, specifically hepatitis B antigen or surface antigen positivity

Patients who are hepatitis B antibody positive are eligible for this protocol

PRIOR CONCURRENT THERAPY:

Concurrent prednisone allowed provided it is used as brief courses (≤ 7 days) for inflammatory conditions unrelated to CLL
No prior cytotoxic therapy or rituximab for this cancer
No concurrent radiotherapy or other chemotherapy