A Study to Evaluate the Efficacy and Safety of Lenalidomide as Maintenance Therapy for Patients With B-Cell Chronic Lymphocytic Leukemia (CLL) Following Second Line Therapy

This is a phase 3, randomized (computer assigned by chance to treatment arm), study being completed an multiple sites to compare the safety and efficacy (how well a drug works) of lenalidomide maintenance therapy to placebo (dummy capsule that contains no lenalidomide or active substances) maintenance therapy. Patients are assigned by a computer with a 50/50 chance to receive placebo or lenalidomide study treatment. Study drug will be taken once each day until the patient discontinues the study. Patients will remain on study drug until progression of disease. Patients will visit their study doctor every 28 days until disease progression to complete safety and efficacy assessments. Quality of life assessments will be completed every other month. If a patient who discontinue study drug prior to disease progression (i.e. due to an adverse reaction to the study drug), they will continue to visit the study doctor each month to complete the efficacy assessments up to progression of disease. Safety assessments may include laboratory blood tests, ECG tests and questions about any medical conditions or side effects experienced during the study. Efficacy assessments may include laboratory blood tests and focused physical exams. Computed tomography (CT) scans along with blood tests and bone marrow samples will be collected to confirm if a patient has improvement of response while on study. After disease progression, patients will be contacted every 12 weeks for survival information, next CLL treatments and quality of life questions. Subjects currently on lenalidomide treatment will discontinue lenalidomide treatment immediately and complete the Treatment Discontinuation assessment. The subjects will then transition to the survival follow-up period.