This clinical trial is focused on studying a type of cancer called Diffuse Large B-cell Lymphoma (DLBCL), which is a common form of non-Hodgkin lymphoma. The trial is comparing the effectiveness of a new treatment called Epcoritamab against standard chemotherapy options chosen by the investigator. Epcoritamab is a type of medication known as a monoclonal antibody, which is designed to help the immune system target and destroy cancer cells. The standard chemotherapy options in this study include combinations like Rituximab, Gemcitabine, and Oxaliplatin (R-GemOx) or Bendamustine and Rituximab (BR).

The purpose of the study is to compare how well Epcoritamab works compared to these standard treatments. Participants in the study will be randomly assigned to receive either Epcoritamab or one of the standard chemotherapy treatments. The study will monitor participants over a period to assess their overall survival, which means how long they live after starting the treatment, and other factors like how long they remain free from cancer progression. The study will also look at the response rate, which is how many participants see a reduction in their cancer, and the duration of response, which is how long the cancer remains reduced.

Participants will receive their assigned treatment and will be regularly monitored through medical assessments, including imaging tests like CT scans or MRI, to track the progress of their disease. The study will also keep track of any side effects or adverse events that participants may experience during the trial. This information will help determine the safety and effectiveness of Epcoritamab compared to the standard chemotherapy options for treating relapsed or refractory DLBCL.