A Study of Mosunetuzumab Alone or With Zanubrutinib in People With Follicular Lymphoma

During Cycle 1, Mosunetuzumab will be administered SC in a step-up dosing schedule at the dose of 5 mg on Day 1, 45 mg on Day 8, and 45 mg on Day 15). Beginning with Cycle 2, Mosunetuzumab will be administered SC at the dose of 45 mg on Day 1. Each Cycle lasts 3 weeks. After the first 8 cycles (approximately 6 months) of therapy, subjects who achieved CR will discontinue therapy, those who attained a PR will receive up to 17 doses (approximately 12 months). Subjects who achieve stable disease (SD) or who experience progressive disease (PD) will be taken off study and subsequent management will be left at the discretion of the investigator.

In Cohort 2, Zanubrutinib is concurrently administered continuously starting on Cycle 1, Day -7 and is given for 12 months in both patients with CR and those with PR. Cohort 2 patients with evidence of circulating lymphoma cells at baseline will initiate Zanubrutinib dosing on Cycle 2 Day 1 and continue dosing for 12 months.