Safety And Efficacy Of Lenalidomide In Patients With Relapsed Or Refractory Aggressive Non-Hodgkin's Lymphoma (NHL)

Inclusion Criteria: 1. Understand and voluntarily sign an informed consent form. 2. Age greater than or equal to 18 years at the time of signing the informed consent form 3. Able to adhere to the study visit schedule and other protocol requirements 4. Biopsy-proven non-Hodgkin's lymphoma 5. Aggressive lymphoma, the following histologies are acceptable: Follicular center lymphoma, grade 3, Diffuse large cell, Mantle cell, Transformed 6. Relapsed or refractory to previous therapy for lymphoma. Patients must have received at least one prior treatment regimen such as radiation, immunotherapy, chemotherapy, or radioimmunotherapy, and be ineligible or unwilling to undergo an autologous stem cell transplant. There is no limit on the number of prior therapies. 7. Patients must have measurable disease on cross sectional imaging that is at least 2 cm in the longest diameter. 8. Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1 or 2. 9. Women of childbearing potential (WCBP) must have a negative serum or urine pregnancy test within 7 days of starting study drug. In addition, sexually active WCBP must agree to use adequate contraceptive methods (oral, injectable, or implantable hormonal contraceptive; tubal ligation; intra-uterine device; barrier contraceptive with spermicide; or vasectomized partner) while on study drug. Exclusion Criteria: 1. Any of the following laboratory abnormalities: 1. Absolute neutrophil count (ANC) \<1,500 cells/mm\^3 (1.5 x 10\^9/L) 2. Platelet count \<100,000/mm\^3 (100 x 10\^9/L) 3. Serum creatinine \>2.5 mg/dL (221 mmol/L) 4. Serum aspartate transaminase (AST) or alanine transaminase (ALT) \>5.0 x upper limit of normal (ULN) 5. Serum total bilirubin \>2.0 mg/dL (34 mmol/L) 2. 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 3. All patients with central nervous system (CNS) disease with the exception of those patients whose CNS disease has been treated with chemotherapy, radiotherapy or surgery and remains asymptomatic, with no active CNS disease, as shown by lumbar puncture, computed tomography (CT) scan or magnetic resonance imaging (MRI), for at least 6 months. 4. Prior history of malignancies other than non-Hodgkin's lymphoma (except for basal cell or squamous cell carcinoma of the skin or carcinoma in situ of the cervix or breast) unless the subject has been free of the disease for \> or equal to 1 year 5. Any serious medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from signing the informed consent form 6. Known positive for human immunodeficiency virus (HIV) 7. Pregnant or lactating females 8. Prior \> or equal to grade 3 National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) allergic reaction/hypersensitivity to thalidomide 9. Prior \> or equal to grade 3 NCI CTCAE rash or any desquamating (blistering) rash while taking thalidomide 10. Prior use of lenalidomide 11. Use of any standard or experimental anti-cancer drug therapy within 28 days of day 1 of study drug therapy 12. Known active Hepatitis C