During this phase, treatment will be received with either odronextamab combined with chemotherapy or rituximab combined with chemotherapy. The specific combination assigned will be determined randomly.

The chemotherapy regimen will consist of cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and either prednisolone or prednisone. This combination is commonly referred to as CHOP or CVP chemotherapy.

Odronextamab or rituximab will be administered through an intravenous infusion, which means the medication will be delivered directly into a vein over a period of time.

Cyclophosphamide and doxorubicin hydrochloride will be given through intravenous administration, delivered directly into a vein.

Vincristine sulfate will be administered by injection.

Prednisolone or prednisone will be taken orally, meaning by mouth in pill or liquid form.

The exact dosages, frequency of administration, and duration of this treatment phase will be determined based on the specific protocol requirements and individual medical assessment.

Throughout the treatment period, regular visits will be scheduled to monitor response to therapy and assess any side effects.

During these visits, imaging tests such as computed tomography scans or magnetic resonance imaging may be performed to evaluate how the lymphoma is responding to treatment.

Blood tests will be conducted to monitor bone marrow function and liver function.

Physical examinations will be performed to assess overall health status and any changes in symptoms.

Any side effects or adverse reactions experienced will be documented and evaluated by the medical team.

At specific timepoints during and after treatment, formal assessments will be conducted to determine how well the lymphoma has responded to therapy.

A key evaluation will occur at 30 months to determine if a complete response has been achieved, meaning that no signs of lymphoma can be detected.

These evaluations will include imaging studies reviewed by independent specialists to provide an objective assessment of treatment response.

The medical team will also assess disease progression and overall survival throughout the study period.

At various points during the trial, questionnaires will be completed to assess physical functioning, overall quality of life, and treatment-related symptoms.

These assessments will help evaluate how the treatment affects daily activities and overall well-being.

The questionnaires will ask about general health status, lymphoma-specific symptoms, and any burden from treatment side effects.

Responses to these questionnaires will be used to understand the impact of treatment from a patient perspective.

After completing the active treatment phase, ongoing follow-up visits will continue to monitor long-term outcomes.

During this period, assessments will focus on whether the lymphoma remains in remission or if any signs of disease progression appear.

The time until any additional lymphoma treatment becomes necessary will be tracked.

Long-term safety monitoring will continue to identify any delayed side effects from the treatment received.

This follow-up period may extend for several years to fully evaluate the durability of treatment response and overall survival.

Throughout the trial, blood samples will be collected to measure odronextamab levels in the bloodstream.

These samples will also be tested to determine if the body has developed any antibodies against odronextamab, which are proteins the immune system might produce in response to the medication.

If antibodies are detected, additional testing will determine if they are neutralizing antibodies, which could potentially affect how well the medication works.

This monitoring will occur both during the period when odronextamab is given with chemotherapy and when it is administered alone.