A Study to Evaluate the Efficacy of Lenalidomide as Maintenance Therapy After Completion of First-line Combination Chemotherapy in Patients With Mantle Cell Lymphoma (MCL).

Inclusion Criteria:

* Histologically-proven mantle cell non-Hodgkin's lymphoma,
* One of the following first-line induction chemotherapy regimens with rituximab: (1) combination regimen containing all of the following components: cyclophosphamide, vincristine, adriamycin and a glucocorticoid; (2) Fludarabine containing regimen such as FC (fludarabine, cyclophosphamide)
* Achieved a PR or better response after the first-line induction chemotherapy regimen (assessed by 2007 Revised Response Criteria for Malignant Lymphoma)
* ECOG performance status score of ≤ 2
* Willing to follow pregnancy precaution

Exclusion Criteria:

* Patients who have received more than 1 line of induction chemotherapy;
* Patients who have received less than 4 cycles of R-CHOP, R-CHOP-like, or R-FC are ineligible;
* Patients who achieved stable disease or progressive disease as best response with first line-induction chemotherapy;
* Any of the following laboratory abnormalities:
* Absolute neutrophil count (ANC) \< 1,500 cells/mm3 (1.5\*10\^9/L)
* Platelet count \< 60,000/mm\^3 (60\*10\^9/L)
* Serum aspartate transaminase (AST/SGOT) or alanine transaminase (ALT/SGPT)) \> 3.0 times upper limit of normal (ULN), except in patients with documented liver involvement by lymphoma
* Serum bilirubin \> 1.5 times ULN, except in case of Gilbert's Syndrome and documented liver involvement by lymphoma
* Calculated creatinine clearance (i.e. Cockcroft-Gault formula) of \< 30 mL /min
* Active or any history of central nervous system (CNS) lymphoma or leptomeningeal involvement by lymphoma
* Subjects at high risk for deep vein thrombosis (DVT) not willing to take DVT prophylaxis
* Known seropositive for or active viral infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV)