We are doing this study to find out if an experimental drug called mosunetuzumab (the study drug) is a safe and effective option for low burden follicular lymphoma. We want to know how well it works in comparison to rituximab, which is the standard drug used to treat people with this diagnosis.

Low Tumor Burden Follicular Lymphoma

Adults ages 18+ who:

• Are diagnosed with classic follicular lymphoma
• Do not have a diagnosis of follicular large B-cell lymphoma
• Have not received any previous systemic therapy to treat their lymphoma (previous radiation therapy of early stage follicular lymphoma is fine)
• Have "low burden" disease that is defined by the following features: an absence of blastoid or large centrocyte cytological features, nodal or extra-nodal tumor that measures less than 7 cm in diameter, an absence of B symptoms, no symptomatic splenomegaly (enlarged spleen), no compression syndrome, and no pleural or peritoneal serous effusion

For more information, contact the study team at nick.jeffries@duke.edu.

If you choose to join this study, you will get a random assignment (like a coin flip) to 1 of 2 groups:

Group 1: If you are in this group, you will get the usual drug (rituximab) used to treat this type of cancer. You will get rituximab 2 ways: through a vein in your arm (IV) and as an injection under the skin. On day 1 of drug cycle 1, you will get the drug as an IV. On Days 8, 15, and 22 of cycle 1, you will get the drug as an injection under the skin. The term "drug cycle" is used to refer to the dosing timelines that are used for this study. One cycle is 56 days, and participants in Group 1 will go through 5 drug cycles. For cycles 2-5, you will get rituximab only on day 1 of each cycle. It is given as an injection under the skin. The rituximab regimen may last up to about 10 months.

Group 2: If you are in this group, you will get the study drug as an injection under the skin. In cycle 1, you will get this drug on days 1, 8, and 15. For cycles 2-8, you will get the study drug only on day 1 of each cycle. The study drug regimen may last up to about 6 months. The drug is given for 8 cycles. One cycle is 21 days.