A Dose Escalation Study of Lenalidomide in Relapsed or Refractory B-cell Chronic Lymphocytic Leukemia

Inclusion Criteria: * Documented diagnosis of B-cell CLL that has relapsed after or is refractory to at least one prior regimen. The prior regimen(s) must have included an alkylating agent and fludarabine (used in combination or separately) * ECOG \< or = 2 * Willing to agree to follow the pregnancy precautions. Exclusion Criteria: * Pregnant or nursing women * Systemic treatment for B-cell CLL within 28 days of study start * Central nervous system involvement * History of renal failure requiring dialysis * Prior treatment with lenalidomide * Alemtuzumab therapy within 56 days of initiating lenalidomide treatment * ANC \< 1000 / ul * Platelet count \< 50,000 / ul * Calculated creatinine clearance \< 60 mL/min (Cockroft-Gault method) * AST or ALT \> 3.0 x upper limit of normal * Serum total bilirubin \> 2.0 mg/dl * Neuropathy \> or = Grade 2 * Uncontrolled autoimmune hemolytic anemia or thrombocytopenia * Richter's transformation (active)