Evaluation of the Efficacy and Safety of Polatuzumab Vedotin Combined With Rituximab, Gemcitabine, and Oxaliplatin (Pola-R-GemOx) as Salvage Therapy for Relapsed/Refractory Diffuse Large B-Cell Lymphoma (DLBCL) Patients Ineligible for Autologous Transplantation

This study is testing a combination chemotherapy regimen — polatuzumab vedotin, rituximab, gemcitabine, and oxaliplatin (Pola-R-GemOx) — as a second-line treatment for people with diffuse large B-cell lymphoma (DLBCL) that has returned or stopped responding to initial treatment and who are not candidates for a stem cell transplant. **You may be eligible if...** - You are 18 or older with a confirmed diagnosis of DLBCL (or certain related types) - Your cancer has come back or is not responding after one prior treatment that included rituximab and an anthracycline chemotherapy - You are not eligible for a stem cell transplant - You have at least one measurable tumor on a scan - Your organ function (blood, liver, kidneys) meets the study requirements **You may NOT be eligible if...** - You have had more than one prior line of treatment - You are eligible for and would benefit from a stem cell transplant - Your cancer does not express the CD79b protein - You have serious heart, liver, or kidney problems - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.