Pentostatin, Cyclophosphamide, and Rituximab With or Without Bevacizumab in Treating Patients With B-Cell Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma

DISEASE CHARACTERISTICS:

* Diagnosis of 1 of the following:

  * Biopsy proven small lymphocytic lymphoma (SLL)
  * Chronic lymphocytic leukemia (CLL)\* as evidenced by the following criteria:

    * Peripheral blood lymphocyte count \> 5,000/mm³ consisting of small to moderate size lymphocytes
    * Immunophenotyping consistent with CLL, defined by the following:

      * The predominant population of lymphocytes share both B-cell antigens (CD19, CD20, or CD23) as well as CD-5 in the absence of other pan-T-cell markers (CD-3 or CD-2)
      * Dim surface immunoglobulin expression
      * Exclusively kappa and lambda light chains
    * Negative FISH analysis for t(11;14)(IgH/CCND1) on peripheral blood or tissue biopsy samples NOTE: \*Splenomegaly, hepatomegaly, or lymphadenopathy are not required for the diagnosis of CLL
* Has ≥ 1 of the following indications\*\* for chemotherapy:

  * Evidence of progressive marrow failure as manifested by the development of or worsening anemia (hemoglobin ≤ 11 g/dL) and/or thrombocytopenia (platelet count ≤ 100,000/mm³)
  * Symptomatic or progressive lymphadenopathy, splenomegaly or hepatomegaly
  * Has ≥ 1 of the following disease-related symptoms:

    * Weight loss \> 10% within the past 6 months
    * Extreme fatigue attributed to CLL
    * Fevers \> 100.5\^oF for 2 weeks without evidence of infection
    * Night sweats without evidence of infection
  * Progressive lymphocytosis (not due to the effects of corticosteroids) with an increase of \> 50% over a 2-month period or an anticipated doubling time of \< 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 indications for study treatment

PATIENT CHARACTERISTICS:

* Eastern Cooperative Oncology Group performance status 0-3
* Life expectancy ≥ 12 months
* Total bilirubin ≤ 3.0 times upper limit of normal (ULN) (unless due to Gilbert's disease)

  * Direct bilirubin \< 1.5 mg/dL (in patients with Gilbert's disease)
* Serum glutamate oxaloacetate transaminase ≤ 3.0 times ULN (unless due to hepatic involvement by CLL)
* Creatinine ≤ 1.5 times ULN
* Urine protein:creatinine ratio \< 1.0 OR \< 1 g of protein by 24-hour urine collection
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception during and for 12 months after completion of study treatment
* Willing to provide mandatory blood and tissue samples
* None of the following cardiovascular conditions:

  * NYHA class III-IV heart disease
  * Myocardial infarction within the past 6 months
  * Unstable angina
  * Stroke, cerebrovascular accident, or transient ischemic attack within the past 6 months
  * Arterial thromboembolic events within the past 12 months
  * Clinically significant peripheral vascular disease
  * Uncontrolled hypertension, defined as systolic BP \> 150 mm Hg or diastolic BP \> 100 mm Hg

    * Hypertension allowed provided it is controlled with a stable anti-hypertensive regimen
  * History of hypertensive crises or hypertensive encephalopathy
  * Deep venous thromboses or pulmonary embolism within the past 12 months
* No evidence of bleeding diathesis or coagulopathy
* No uncontrolled or active hemolytic anemia requiring immunosuppressive therapy or other pharmacologic treatment
* No active or recent history (within the past 30 days) of hemoptysis (≥ ½ teaspoon of bright red blood per episode)
* No abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within the past 6 months
* No active peptic ulcer disease
* No serious non-healing wound, ulcer, or bone fracture
* No significant traumatic injury within the past 28 days
* No uncontrolled infection
* No active HIV infection
* No other active primary malignancy (except nonmelanoma skin cancer or carcinoma in situ of the cervix) requiring treatment or limiting survival to ≤ 2 years
* No psychiatric or addictive disorders or other conditions that, in the opinion of the investigator, would preclude study participation

PRIOR CONCURRENT THERAPY:

* Prior corticosteroids allowed
* More than 4 weeks since prior radiotherapy
* More than 28 days since prior and no concurrent major surgical procedure or open biopsy
* More than 7 days since prior minor surgical procedure, fine needle aspiration, or core biopsy (other than bone marrow biopsy)
* No concurrent therapeutic doses of coumadin-derivative anticoagulants (e.g., warfarin)

  * Doses of ≤ 2 mg daily allowed for prophylaxis of thrombosis
  * Prophylactic doses of low molecular weight heparin allowed
* No other concurrent investigational agents for treatment of CLL or SLL
* No other concurrent specific anticancer treatment except hormonal therapy