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

OBJECTIVES:

- To determine the frequency of response in patients with previously untreated,
intermediate- or high-risk B-cell chronic lymphocytic leukemia (CLL) treated with
pentostatin, cyclophosphamide, and rituximab.

- To characterize the toxicity of this regimen in these patients.

OUTLINE: Patients receive cyclophosphamide IV followed by pentostatin IV on day 1 in course
1. Beginning in course 2 and in all subsequent courses, patients receive cyclophosphamide IV
on day 1, pentostatin IV on day 1, and rituximab IV on day 1 or on days 1 and 2. Treatment
repeats every 3 weeks for up to 6 courses in the absence of disease progression or
unacceptable toxicity.

After completion of study treatment, patients are followed at least every 3 months for 1
year.

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