Rituximab, Pentostatin, Cyclophosphamide, and Lenalidomide in Treating Patients With Previously Untreated B-Cell Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma

DISEASE CHARACTERISTICS:

* Diagnosis of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), meeting the following criteria:

  * Biopsy-proven SLL according to WHO criteria
  * CLL diagnosis\* according to NCI working group criteria as evidenced by all of the following:

    * Peripheral blood lymphocyte count of \> 5,000/mm³
    * Small to moderate peripheral blood lymphocyte with \< 55% prolymphocytes
    * Immunophenotyping consistent with CLL defined as:

      * B-cell markers with CD5 antigen in the absence of other pan-T-cell markers (e.g., CD3, CD2)
      * CD19, CD20, or CD23
      * Dim surface immunoglobulin expression
      * Exclusively kappa or lambda light chains
    * Diagnosis of mantle cell lymphoma must be excluded by negative FISH analysis for t(11;14)(IgH/CCND1) on peripheral blood or tissue biopsy or negative immunohistochemical stains for cyclin D1 on involved tissue biopsy NOTE: \*Splenomegaly, hepatomegaly, or lymphadenopathy are not required for the diagnosis of CLL
* Previously untreated disease and meets ≥ 1 of the following criteria\*:

  * At least 1 or more of the following disease-related symptoms:

    * Weight loss \> 10% within the previous 6 months
    * Extreme fatigue attributed to CLL
    * Fevers \> 100.5º F for 2 weeks without evidence of infection
    * Night sweats without evidence of infection
  * Evidence of progressive marrow failure as manifested by the development of or worsening anemia (i.e., hemoglobin ≤ 11 g/dL) and/or thrombocytopenia (i.e., platelet count ≤ 100,000/mm³) not due to autoimmune disease
  * Symptomatic or progressive lymphadenopathy, splenomegaly, or hepatomegaly
  * Progressive lymphocytosis due to CLL with an increase of \> 50% over a 2-month period or an anticipated doubling time \< 6 months NOTE: \*Marked hypogammaglobulinemia or the development of a monoclonal protein in the absence of any of the above criteria for active disease are not sufficient for protocol therapy

PATIENT CHARACTERISTICS:

* ECOG performance status 0-3
* Serum creatinine ≤ 1.5 times upper limit of normal (ULN)
* Total bilirubin ≤ 3.0 times ULN (unless due to Gilbert disease)

  * Direct bilirubin \< 1.5 mg/dL for Gilbert disease to be diagnosed if total bilirubin \> 3.0 times ULN
* AST and ALT ≤ 3.0 times ULN (unless due to hemolysis or CLL)
* Willing to provide blood samples
* Able to take acetylsalicylic acid (ASA) (81 or 325 mg) daily as prophylactic anticoagulation (patients intolerant to ASA may use low molecular weight heparin)
* Not pregnant or nursing
* Negative pregnancy test
* Female patients must use effective double-method contraception beginning 1 month prior to, during, and for 4 weeks after completion of study treatment
* Male patients must use effective contraception during and for 4 weeks after completion of study treatment
* No comorbid conditions, including any of the following:

  * New York Heart Association class III or IV heart disease
  * Recent myocardial infarction (\< 1 month)
  * Uncontrolled infection
  * Infection with HIV/AIDS
* No other active primary malignancy requiring treatment or that limits survival to ≤ 2 years
* No history of deep venous thrombosis or pulmonary embolism ≤ 12 months prior to study registration
* No active hemolytic anemia requiring immunosuppressive or other pharmacologic therapy

PRIOR CONCURRENT THERAPY:

* See Disease Characteristics
* No prior chemotherapy or monoclonal antibody-based therapy for treatment of CLL
* Nutraceutical treatments with no established benefit in CLL (e.g., epigallocatechin gallate or other herbal treatments) are not considered prior therapy
* More than 4 weeks since prior radiotherapy
* At least 4 weeks since prior major surgery
* No concurrent corticosteroids

  * Concurrent low doses of steroids (e.g., \< 10 mg of prednisone or equivalent dose of other steroid) used for treatment of non-hematologic medical conditions allowed
  * Prior use of corticosteroids allowed
* No prior thalidomide or lenalidomide
* No concurrent therapeutic doses of coumadin-derivative anticoagulants (e.g., warfarin)

  * Doses of ≤ 2 mg daily allowed for thrombosis prophylaxis
  * Prophylactic doses of low molecular weight heparin allowed