This clinical trial is focused on studying a type of cancer called follicular lymphoma, which is a form of non-Hodgkin lymphoma. The trial is investigating a new treatment called odronextamab, also known by its code name REGN1979. Odronextamab is a special type of medication known as a bispecific antibody, which is designed to target specific proteins on cancer cells. The study aims to compare the effectiveness and safety of odronextamab with a commonly used treatment involving rituximab combined with various chemotherapy drugs, including vincristine sulfate, bendamustine hydrochloride, doxorubicin hydrochloride, cyclophosphamide, and prednisone.

The purpose of the study is to determine how well odronextamab works and how safe it is for patients who have not been treated for follicular lymphoma before. The study is divided into two parts. In the first part, the focus is on assessing the safety and tolerability of odronextamab. In the second part, participants will be randomly assigned to receive either odronextamab or the standard treatment with rituximab and chemotherapy. The study will monitor the participants over a period to see how well the treatments work in achieving a complete response, which means the disappearance of all signs of cancer.

Participants in the study will receive their assigned treatment and will be closely monitored by healthcare professionals. The study will involve regular check-ups and tests, such as imaging scans like MRI or CT scans, to track the progress of the treatment. The trial is expected to continue for several years to gather comprehensive data on the long-term effects and benefits of the treatments being studied.