FDA Approves Subcutaneous Mosunetuzumab in Follicular Lymphoma

The US FDA has approved mosunetuzumab-axgb (Lunsumio VELO) as a subcutaneous (SC) formulation for the treatment of adult patients with relapsed/refractory (R/R) follicular lymphoma (FL) after 2 or more lines of systemic therapy.¹

This approval stems from the results of the phase 1/2 GO29781 study (NCT02500407).

Mosunetuzumab is a CD20 and CD3 bispecific antibody. As a subcutaneous formulation,  it reduces administration time with an approximately 1-minute injection compared with a 2-to-4-hour intravenous (IV) infusion.

“Since [FL] often requires lifelong management, reducing the burden of care for these [patients] is of paramount importance,” said Levi Garraway, MD, PhD, chief medical officer and head of Global Product Development of Genentech, in a news release. “With this FDA approval, treatment can now be administered in just [1] minute, which significantly reduces the time patients spend in the clinic and helps to align care with their individual needs and preferences.”

About the GO29781 Study

The multicenter, open-label phase 1/2 study evaluated mosunetuzumab in patients with third-line or later FL. The objective response rate and complete response rate in patients treated with mosunetuzumab were 75% (95% CI, 64%–83%) and 59% (95% CI, 48%–69%), respectively. The median duration of response was 22.4 months (95% CI, 16.8–22.8).

The most common adverse events (AEs) were injection site reactions, fatigue, rash, cytokine release syndrome (CRS), COVID-19 infection, musculoskeletal pain, and diarrhea. The CRS rate was 30% and AEs were mostly low grade (grade 1–2, 28%; grade 3, 2.1%), occurred during the first cycle, and were resolved after a median duration of 2 days.

The study evaluated the safety, efficacy, and pharmacokinetics of the agent administered both as an IV and SC treatment in patients with R/R B-cell non-Hodgkin lymphoma. Mosunetuzumab is being investigated as a monotherapy and in combination with other agents.

Genentech, developer of the agent, is evaluating mosunetuzumab in multiple ongoing phase 3 studies in earlier lines of treatment. The SUNMO (NCT05171647)² study is evaluating mosunetuzumab in combination with polatuzumab vedotin-piiq (Polivy) in patients with second-line or later large B-cell lymphoma, and the MorningLyte (NCT06284122)³ study is investigating mosunetuzumabin combination with lenalidomide (Revlimid) in patients with previously untreated FL.

“This approval is a significant step in broadening access to effective treatments for people living with [FL],” said Ian Flinn, MD, PhD, Tennesse Oncology and One Oncology in a news release.¹ “With its manageable [CRS] profile and reduced administration time, [SC mosunetuzumab] enables oncologists to deliver advanced care in community practice settings.”

REFERENCES

1.FDA approves Genentech’s Lunsumio VELO for subcutaneous use in relapsed or refractory follicular lymphoma. Genentech. News release. December 21, 2025. Accessed December 22, 2025. https://tinyurl.com/5n6knczc

2.A study evaluating efficacy and safety of mosunetuzumab in combination with polatuzumab vedotin compared to rituximab in combination with gemcitabine plus oxaliplatin in participants with relapsed or refractory aggressive B-cell non-Hodgkin’s lymphoma (SUNMO). ClinicalTrials.gov. Updated November 12, 2025. Accessed December 22, 2025. https://www.clinicaltrials.gov/study/NCT05171647

3.Study of mosunetuzumab plus lenalidomide compared to anti-CD20 anti-body + chemotherapy in follicular lymphoma FLIPI2-5 (MorningLyte). ClinicalTrials.gov. Updated October 15, 2024. Accessed December 22, 2025. https://www.clinicaltrials.gov/study/NCT06284122