The purpose of this study is to determine the recommended dose of CMC544 administered in combination with rituximab (R-CMC544), and in alternance with rituximab, gemcitabine and oxaliplatin (R-GEMOX) in the first phase of the study. After that, efficacy and safety of this combination will be evaluated preliminarily in patients with DLBCL in relapse or refractory, who are no candidates for autologous transplant.