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

Ages Eligible for Study: Between 60 and 80 years old Genders Eligible for Study: Both Accepts Healthy Volunteers: No Inclusion Criteria: For patients registered at the time of initial diagnosis * Patient with histologically proven CD20+ diffuse large B cel LYMPHOMA (DLBCL) 5WHO classification 2008) including clinical subtypes (primitive mediastinal, intravascular, etc.). Patients with De Novo Transformed DLBCL from low grade lymphoma (Follicular, other..) may also be included. Patients with DLBCL associated with some small cell infiltration in bone marrow may also be included Or CD20+ B-cell lymphoma with intermediate features between DLBCL and Burkitt or with intermediate features between DLBCL and classical Hodgkin lymphoma Or CD20+ Follicular lymphoma grade 3B Or CD20+ Aggressive B-cell lymphoma unclassifiable * previous untreated with chemo- or radiotherapy For patients registered after response evaluation to first line treatment with R-CHOP: * Patient with histologically proven CD20+ diffuse large B cell LYMPHOMA (DLBCL) 5WHO classification 2008) including clinical subtypes (primitive mediastinal, intravascular, etc.). Patients with De Novo Transformed DLBCL from low grade lymphoma (Follicular, other..) may also be included. Patients with DLBCL associated with some small cell infiltration in bone marrow may also be included Or CD20+ B-cell lymphoma with intermediate features between DLBCL and Burkitt or with intermediate features between DLBCL and classical Hodgkin lymphoma Or CD20+ Follicular lymphoma grade 3B Or CD20+ Aggressive B-cell lymphoma unclassifiable * Have reached a CR or PR after first line treatment with at least 6 cycles of R-CHOP 14 regimens and up to 8 cycles of R-CHOP21 * Previously untreated with Radiotherapy For all patients: * aged from 60 to 80 years at time of registration * Ann Arbor stages II-IV at time of initial diagnosis * aaIPI\> 1 at time of initial diagnosis * ECOG performance status 0-2 * Minimum life expectancy of 3 months * Following laboratory values at screening: * ANC≥ 1000.10\^6/L and Platelets≥60000.10\^6/L * AST\<5\*ULN, ALT\<5\*ULN, Total Bilirubin\<1,5\*ULN * Creatinine clearance\>30mL/min * Women are are using effective contraception, are not pregnant and agree not to become pregnant during participation in the trial and after end of study. Men agree not to father a child during participation in the trial and during the 12 months thereafter. * Having previously signed a written informed consent form Exclusion Criteria: * Any other histological type of Lymphoma, Burkitt included. * Any history of treated or non treated small B-cell lymphoma * Central nervous system or meningeal involvement by lymphoma * Contraindication to any drug contained in the chemotherapy regimen Myocardial infarction during last 3 months or unstable coronary disease or uncontrolled chronic symptomatic congestive heart insufficiency NYHA III-IV * Uncontrolled hypertension * Uncontrolled diabetes mellitus as defined by the investigator * Active systemic infection requiring treatment * previously known HIV positive serology * Active hepatitis B or C * Prior history of malignancies other than lymphoma within 3 years * Serious medical or psychiatric illness