This clinical trial studies lenalidomide as chemoprevention in treating patients with high-risk, early stage B-cell chronic lymphocytic leukemia (B-CLL). Chemoprevention is the use of certain drugs to keep cancer from forming. The use of lenalidomide may slow disease progression in patients with early stage B-cell chronic lymphocytic leukemia

PRIMARY OBJECTIVES:

I. To determine time to progression in patients with high risk CLL.

SECONDARY OBJECTIVES:

I. Overall response rate including (complete remission [CR]+partial remission [PR]) of lenalidomide.

II. To determine the incidence of immune mediated flare reaction. III. To characterize the toxicity profile of single agent lenalidomide in previously untreated B-CLL.

IV. To correlate expression of B-CLL co-stimulatory ligands and clinical efficacy of lenalidomide in this patient population.

V. To conduct correlative studies.

OUTLINE: Patients receive lenalidomide orally (PO) once daily for 4 weeks. Treatment repeats every 4 weeks for up to 12 courses in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up at 30 days and then every 3 months for 5 years.

Inclusion Criteria:

Patients must have a definitive diagnosis of B-CLL as defined by the International Workshop on CLL (IWCll) criteria Patient must have early stage B-CLL defined as Rai stage 0, 1 or 2 Patients must not have received any prior treatment for management of B-CLL

Patients must be assessed to have high risk B-CLL as defined by either one of the following criterion:

• High-risk cytogenetics (either 17p deletion or 11q deletion);
• Unmutated immunoglobulin heavy chain gene rearrangement Patents must understand and voluntarily sign an informed consent form Able to adhere to the study visit schedule and other protocol requirements Patients must have measurable disease either an absolute lymphocyte counts (ALC) of more than 5,000/ul or measurable lymphadenopathy or organomegaly Eastern Cooperative Oncology Group (ECOG) performance status of =< 2 at study entry Females of childbearing potential (FCBP) must have a negative serum or urine pregnancy test with a sensitivity of at least 50 mIU/mL 10-14 days prior to and again within 24 hours before starting lenalidomide and must either commit to continue abstinence from heterosexual intercourse or begin TWO acceptable methods of birth control, one highly effective method and one additional effective method AT THE SAME TIME, at least 28 days before she starts taking lenalidomide; FCBP must also agree to ongoing pregnancy testing; men must agree to use a latex condom during sexual contact with a FCBP even if they have had a successful vasectomy; all patients must be counseled at a minimum of every 28 days about pregnancy precautions and risks of fetal exposure Able to take aspirin (81 or 325mg) or warfarin sodium daily as prophylactic anticoagulation Absolute neutrophil count >= 1.0 x 10^9/L Platelet count >= 30 x 10^9/L Serum creatinine =< 1.5 x upper limit of normal (ULN) Total bilirubin =< 1.5 mg/dL Aspartate aminotransferase (AST/SGOT) and alanine aminotransferase (ALT/SGPT) < 2 x ULN or =< 5 x ULN if hepatic metastases are present

Exclusion Criteria:

Any serious medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from signing the informed consent form Pregnant or lactating females (lactating females must agree not to breast feed while taking lenalidomide) Any condition, including the presence of laboratory abnormalities, which places the subject at unacceptable risk if he/she were to participate in the study or confounds the ability to interpret data from the study Use of any other experimental drug or therapy within 28 days of baseline Known hypersensitivity to thalidomide or lenalidomide Prior history of development of erythema nodosum if characterized by a desquamating rash while taking thalidomide or similar drugs Patients who have been treated with any prior therapy for B-CLL Patients with history of any other cancer (except non-melanoma skin cancer or carcinoma in-situ of the cervix, unless in complete remission and off therapy for that disease for > 3 years) Patient with history of cardiac arrest within the past 6 months Any prior use of lenalidomide Concurrent use of other anti-cancer agents or treatments Known history of hepatitis B or C Known human immunodeficiency virus (HIV) positive status