Topline findings: GO29781 trial
- Efficacy: 75% objective response rate and 59% complete response rate in third-line or later FL.
- Durability: Median duration of response reached 22.4 months.
- Safety: Cytokine release syndrome occurred in 30% of patients, was largely low grade, and typically resolved within two days.
- Administration advantage: One-minute subcutaneous dosing designed to reduce clinic time and treatment burden.
The FDA has approved subcutaneous (SC) Lunsumio VELO (mosunetuzumab) for the treatment of adult patients with relapsed or refractory (R/R) follicular lymphoma (FL) following two or more lines of systemic therapy.1
The approval of Lunsumio VELO, a CD20xCD3 bispecific, is based on data from the Phase I/II GO29781 clinical trial (NCT02500407).
In a company press release, Levi Garraway, MD, PhD, Roche’s chief medical officer and head of global product development, said: “Since follicular lymphoma often requires lifelong management, reducing the burden of care for these individuals is of paramount importance. 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.”
Earlier in November, the European Commission granted conditional marketing authorization to SC Lunsumio for the same indication.2
GO29781 trial results
- In the GO29781 study, Lunsumio VELO achieved a 75% objective response rate (ORR) and a 59% complete response rate (CRR) in patients with third-line or later FL.
- The median duration of response (DoR) was 22.4 months, indicating durable clinical benefit.
- The most common adverse reactions (≥20%) included injection-site reactions, fatigue, rash, cytokine release syndrome (CRS), COVID-19 infection, musculoskeletal pain, and diarrhea.
- CRS occurred in 30% of patients, was predominantly low grade, and typically arose during Cycle 1.
- CRS events resolved within a median of two days, with few Grade 3 cases and no unresolved events.
Ian Flinn, MD, PhD, Tennessee Oncology and One Oncology, added: “This approval is a significant step in broadening access to effective treatments for people living with follicular lymphoma. With its manageable cytokine release syndrome profile and reduced administration time, Lunsumio VELO enables oncologists to deliver advanced care in community practice settings.”
Trial design
- GO29781 is a multicenter, open-label study in patients with relapsed or refractory B-cell non-Hodgkin lymphoma.
- The trial used a dose-escalation and expansion design to evaluate mosunetuzumab.
- Mosunetuzumab was administered via both intravenous and SC routes.
- The study assessed safety, efficacy, and pharmacokinetics of mosunetuzumab.
- Regulatory efficacy was based on ORR and DoR.
First FDA approval in 2022
Lunsumio was first approved by the FDA as an intravenous infusion for the treatment of adult patients with R/R FL following two or more lines of systemic therapy in December 2022.3
The original approval was based on earlier outcomes from GO29781.
- In heavily pretreated FL, Lunsumio achieved an 80% ORR, with a 60% CRR.
- Responses were durable, with 57% of patients maintaining benefit for at least 18 months and a median DoR of 22.8 months.
- Efficacy was observed in patients at high risk of progression and those refractory to prior therapies.
- CRS was the most common adverse event (39%), with a median duration of 3 days.
- Other frequent adverse events (≥20%) included fatigue, rash, pyrexia, and headache.
In a company statement from the time, Elizabeth Budde, MD, PhD, hematologic oncologist and associate professor, City of Hope Division of Lymphoma, Department of Hematology & Hematopoietic Cell Transplantation, and Lunsumio clinical trial investigator, said: “This approval is a significant milestone for people with relapsed or refractory follicular lymphoma, who have had limited treatment options until now. As a first-in-class T-cell engaging bispecific antibody that can be initiated in an outpatient setting, Lunsumio’s high response rates and fixed-duration could change the way advanced follicular lymphoma is treated.”
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 22, 2025. https://www.roche.com/media/releases/med-cor-2025-12-22
2. European Commission Approves Subcutaneous Mosunetuzumab in R/R Follicular Lymphoma. OncLive. November 19, 2025. Accessed December 22, 2025. https://www.onclive.com/view/european-commission-approves-subcutaneous-mosunetuzumab-in-r-r-follicular-lymphoma
3. FDA Approves Genentech’s Lunsumio, a First-in-Class Bispecific Antibody, to Treat People With Relapsed or Refractory Follicular Lymphoma. News release. Genentech. December 22, 2022. Accessed December 22, 2025. https://www.gene.com/media/press-releases/14978/2022-12-22/fda-approves-genentechs-lunsumio-a-first