Study of Lenalidomide Maintenance Versus Placebo in Responding Elderly Patients With DLBCL and Treated With R-CHOP

Patients should have received at least 6 and up to 8 cycles of the R-CHOP 14 or R-CHOP 21 regimen or 6 R-CHOP-14 or -21 completed by 2 Rituximab alone in accordance to local preferences. Patients can be registered to participate in the study at two time points: * At time of initial diagnosis and study enrolment (signature of informed consent) before the first cycle of treatment with R-CHOP. * At randomization (signature of informed consent) after treatment in first line with R-CHOP and have reached at least PR or CR. Evaluation of the response to R-CHOP must be in accordance with Revised Response Criteria for Malignant Lymphoma(2007). Stratification: Before randomization, the patients will be stratified according to the country and the response to R-CHOP (PR vs CR). Randomization: Patients in CR/PR after R-CHOP will be randomized to maintenance therapy with lenalidomide or placebo.