FDA Approves Subcutaneous Mosunetuzumab for R/R Follicular Lymphoma

The subcutaneous version of mosunetuzumab can be initiated and maintained in the outpatient setting.

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The FDA has granted approval to a subcutaneous formulation of mosunetuzumab (Lunsumio VELO; Genentech/Roche) for the treatment of adult patients with relapsed or refractory (R/R) follicular lymphoma (FL) who have received 2 or more prior lines of systemic therapy.1

Mosunetuzumab is now the first subcutaneous bispecific antibody available for this indication. Previously, the treatment was approved as a 2- to 4-hour intravenous (IV) infusion.2 The new subcutaneous formulation is administered as a fixed-duration, approximately 1-minute injection.

“Since follicular lymphoma often requires lifelong management, reducing the burden of care for these individuals is of paramount importance,” Levi Garraway, MD, PhD, Roche’s chief medical officer and head of global product development, said in a statement.1 “With this FDA approval, treatment can now be administered in just one minute, which significantly reduces the time patients spend in the clinic and helps to align care with their individual needs and preferences.”

The approval was supported by pivotal data from the phase 1/2 GO29781 trial (NCT02500407), which demonstrated pharmacokinetic non-inferiority to the IV formulation and a consistent benefit-risk profile.

The European Union approved this formulation more than a month earlier in November.3

Efficacy Data From GO29781

The approval was primarily based on results from the subcutaneous cohort of the multicenter, open-label GO29781 study. In patients with R/R FL who had received at least 2 prior lines of therapy—including an anti-CD20 antibody and an alkylating agent—subcutaneous mosunetuzumab demonstrated an overall response rate (ORR) of 74.5% (95% CI, 64.4%-82.9%) and a complete response (CR) rate of 58.5% (95% CI, 46.9%-68.6%). Responses were found to be durable, with a median duration of CR (DOCR) of 20.8 months (95% CI, 18.8-NE).

Pharmacokinetic analyses confirmed that the SC delivery achieved non-inferior exposure levels compared with the IV route, ensuring that the transition to the more convenient injection does not compromise therapeutic efficacy.

Safety Profile and Administration

The safety profile of subcutaneous mosunetuzumab was consistent with the known effects of the IV formulation, with the addition of local injection-site reactions. The most common adverse events (AEs) of any grade included injection-site reactions (60.6%), fatigue (35.1%), and cytokine release syndrome (CRS; 29.8%).

CRS events were predominantly low-grade and manageable. Grade 1 or 2 CRS occurred in 27.7% of patients, while grade 3 CRS was reported in only 2.1%. All CRS events occurred during the first cycle of treatment and resolved within a median of 2 days. To mitigate the risk of CRS, the therapy utilizes a step-up dosing schedule during the first cycle.

With the manageable safety profile and the 1-minute administration time, subcutaneous mosunetuzumab can be initiated and maintained in the outpatient setting. The treatment is designed for a fixed duration of approximately 6 to 12 months, allowing patients the possibility of a treatment-free period following the completion of their regimen.

“This approval is a significant step in broadening access to effective treatments for people living with follicular lymphoma,” said Ian Flinn, MD, PhD, Tennessee Oncology and One Oncology.1 “With its manageable cytokine release syndrome profile and reduced administration time, Lunsumio VELO enables oncologists to deliver advanced care in community practice settings.”

References

1. FDA approves Roche’s Lunsumio VELO for subcutaneous use in relapsed or refractory follicular lymphoma. News release. Roche. December 21, 2025. Accessed December 23, 2025. https://www.roche.com/media/releases/med-cor-2025-12-22

2. Joszt L. FDA approves bispecific antibody mosunetuzumab for R/R follicular lymphoma. AJMC®. December 23, 2022. Accessed December 17, 2025. https://www.ajmc.com/view/fda-approves-bispecific-antibody-monsunetuzumab-for-r-r-follicular-lymphoma

3. European Commission approves Roche’s Lunsumio subcutaneous for relapsed or refractory follicular lymphoma. News release. Roche. November 18, 2025. Accessed December 17, 2025. https://www.roche.com/media/releases/med-cor-2025-11-19