Eligible patients will be randomized to treatment with pixantrone plus rituximab or gemcitabine plus rituximab in up to six 28-day cycles. At the time patients experience progressive disease during study treatment, early follow- up, or intermediate follow-up, they enter the survival follow up period. Patients who complete study treatment or discontinue study treatment for any other reason will participate in the follow-up periods.~Early Follow-Up: After treatment completion or discontinuation, patient will enter a 24-week follow-up period.~Intermediate Follow-Up: After completing the 24-week early follow-up period, patient will enter an additional 72-week follow-up period.~Survival Follow-Up: All patients will be monitored for survival.
The purpose of this study is to evaluate the efficacy of Pixantrone + Rituximab compared to Gemcitabine + Rituximab in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), or follicular grade 3 lymphoma.