ASH 2022: Phase II Study Results With Mosunetuzumab in Resistant Follicular Lymphoma

By: Kayci Reyer
Posted: Friday, January 6, 2023

Mosunetuzumab therapy, a CD20 x CD3 T-cell–engaging bispecific monoclonal antibody, may lead to durable clinical response and prolonged tolerability in some patients with relapsed or refractory follicular lymphoma, according to findings from an updated analysis from a phase II trial presented at the 2022 American Society of Hematology (ASH) Annual Meeting and Exposition (Abstract 610). Mosunetuzumab therapy, a fixed-duration treatment used in outpatient care, has previously been shown to result in a high complete response rate with manageable toxicities. On December 22, the U.S. Food and Drug Administration granted accelerated approval to this agent for this patient population.

“Compared with [patients’] last prior therapy, [mosunetuzumab] demonstrated higher [objective response rates and complete response] rates, with longer [duration of response, duration of complete response, progression-free survival], and time to next therapy, although limitations should be noted for retrospective comparisons and the absence of standardized imaging assessment for the last prior therapy,” concluded Nancy L. Bartlett, MD, of the Washington University School of Medicine, St. Louis, and colleagues.

The study included 90 patients with relapsed or refractory follicular lymphoma who had received at least two prior therapies. At a median follow-up of 26.7 months, the objective response and complete response rates were 77.8% and 60.0%, respectively. Median progression-free survival was not reached, and 2-year progression-free survival was 51.4%. Neither the median duration of response nor the median duration of complete response was reached. Remission endured for at least 24 months in 79.5% of patients who achieved a complete response.

No new cytokine-release syndrome events or significant adverse events were reported between the initial and follow-up analyses. The adverse event–related discontinuation rate was 4.4%. No treatment-related grade 5 adverse events were noted. Among patients experiencing cytokine-release syndrome events (44.4%), the majority (84.5%) occurred during cycle 1, and 97.2% had a severity of grade 1 or 2. Patients who experienced cytokine-release syndrome events had an objective response rate of 77.5% versus 78.0% in those who did not experience such events.

Disclosure: For full disclosure of the study authors, visit ash.confex.com.

2022 ASH Annual Meeting and Exposition

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