This clinical trial is focused on studying the treatment of Diffuse Large B-Cell Lymphoma, a type of cancer that affects the white blood cells. The study will evaluate the effectiveness and safety of a medication called Epcoritamab, also known by its code name GEN3013 or DuoBody-CD3xCD20. Epcoritamab is a solution for injection that is designed to help the immune system target and destroy cancer cells. The trial will also explore the use of Epcoritamab in combination with another medication called Lenalidomide, which is taken orally and works by affecting the immune system to slow or stop the growth of cancer cells.

The purpose of this study is to determine how well Epcoritamab works on its own or when combined with Lenalidomide as a first-line treatment for patients who cannot undergo anthracycline-based therapy, a common chemotherapy treatment. Participants in the study will receive either Epcoritamab alone or in combination with Lenalidomide. Some participants may also receive a placebo. The study will monitor the participants over a period of time to assess the response to the treatment, including how long the response lasts and any side effects that may occur.

Throughout the study, participants will receive regular check-ups and monitoring to ensure their safety and to gather information on how the treatment is affecting their lymphoma. The trial aims to provide valuable insights into the potential benefits of using Epcoritamab, with or without Lenalidomide, for treating Diffuse Large B-Cell Lymphoma, especially for those who are not eligible for standard chemotherapy options.