This study is a multicentric, phase III open-label, randomized trial evaluating the efficacy and safety of R-CHOP given every 14 days compared to R-CHOP given every 21 days in association or not with darbepoetin alfa in order to maintain hemoglobin above 13 g/dl, compared to classical symptomatic treatment of anemia in patients aged 66 to 80 years with not previously treated diffuse large B-cell lymphoma with at least one adverse prognostic factor of the age adjusted IPI.