Sub-Q Mosunetuzumab Approval Simplifies R/R Follicular Lymphoma Care: Zahra Mahmoudjafari, PharmD, MBA, BCOP

The FDA recently approved a subcutaneous formulation of mosunetuzumab (Lunsumio VELO; Genentech/Roche) for adults with relapsed or refractory follicular lymphoma who have received 2 or more prior lines of systemic therapy.¹ The approval made mosunetuzumab the first subcutaneous bispecific antibody available for this indication, administered as a fixed-duration, approximately 1-minute injection rather than a 2- to 4-hour intravenous (IV) infusion.

The agency based its decision on pivotal data from the phase 1/2 GO29781 trial (NCT02500407), specifically results from the subcutaneous cohort.² These demonstrated pharmacokinetic noninferiority to the IV formulation and a consistent benefit-risk profile, ensuring that the transition to the more convenient injection does not compromise therapeutic efficacy.¹ The most common adverse events, however, included injection-site reactions (60.6%), fatigue (35.1%), and cytokine release syndrome (29.8%).

Zahra Mahmoudjafari, PharmD, MBA, BCOP, a clinical pharmacy manager in the division of hematological malignancies and cellular therapeutics within the University of Kansas Health System, discussed the approval during a recent interview with The American Journal of Managed Care^® (AJMC^®). In the first half of the interview, she explained the significance of the mosunetuzumab approval in the current follicular lymphoma treatment landscape. Mahmoudjafari also highlighted the bispecific antibody’s mechanism of action and what sets it apart from other treatments for follicular lymphoma.

“[The] mechanism is quite different from our traditional treatments that we have for follicular lymphoma, which rely on the cytotoxic effects or the immune-mediated cell killing indirectly,” she concluded. “The bispecific antibodies create a synthetic immune synapse, actively engaging these T cells to eliminate the malignant B cells. It's really nice and unique, and one of the reasons we've seen so many meaningful responses, even in patients who have heavily pretreated disease.”

References

1. Joszt L. FDA approves subcutaneous mosunetuzumab for R/R follicular lymphoma. AJMC. December 22, 2025. Accessed March 17, 2025. https://www.ajmc.com/view/fda-approves-subcutaneous-mosunetuzumab-for-r-r-follicular-lymphoma
2. A safety, efficacy and pharmacokinetic study of BTCT4465A (mosunetuzumab) as a single agent and combined with atezolizumab in non-Hodgkin’s lymphoma (NHL) and chronic lymphocytic leukemia (CLL). ClinicalTrials.gov. Updated September 12, 2025. Accessed March 17, 2026. https://clinicaltrials.gov/study/NCT02500407