CHMP Recommends EU Approval of Subcutaneous Mosunetuzumab in R/R Follicular Lymphoma

The European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) has recommended the approval of a subcutaneous (SC) formulation of mosunetuzumab (Lunsumio) for the treatment of adult patients with relapsed/refractory follicular lymphoma following at least 2 prior lines of systemic therapy.1 The European Commission is expected to issue a final decision in the near future.

The opinion is supported by data from the primary analysis of the phase 1/2 GO29781 study (NCT02500407). Findings from the study demonstrated that patients who received the SC formulation of mosunetuzumab achieved 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, 47.9%-68.6%) per independent review committee assessment. The median duration of CR was 20.8 months (95% CI, 18.8-not evaluable).

Pharmacokinetic noninferiority compared with intravenous (IV) administration was observed with the SC formulation of mosunetuzumab.

"[Mosunetuzumab] was the first-ever approved CD20 x CD3 T-cell engaging bispecific antibody demonstrating high, durable response rates and a favorable safety profile in third-line or later follicular lymphoma," Levi Garraway, MD, PhD, chief medical officer and head of global product development at Roche, stated in a news release. "If approved, the SC formulation could help to expand the treatment options available, offering people a fixed-duration therapy with a faster treatment administration time."

GO29781 was an open-label, multicenter study that examined IV and SC mosunetuzumab as monotherapy or in combination with atezolizumab (Tecentriq) in patients with relapsed/refractory B-cell non-Hodgkin lymphoma and chronic lymphocytic leukemia. In order to be eligible for the study, patients needed to have an ECOG performance status of 0 or 1, a B-cell hematologic malignancy expected to express the cluster of differentiation 20 with no available therapy expected to improve survival, and adequate hepatic, hematologic, and renal function.2

During the dose-expansion portion of the study, patients received IV or SC mosunetuzumab as a single agent or in combination with IV atezolizumab at 1200 mg.

The primary end points were determining the maximum tolerated dose of mosunetuzumab, the rate of adverse effects (AEs), as well as mosunetuzumab and atezolizumab serum concentration. Secondary end points included duration of response (DOR), progression-free survival (PFS), overall survival, ORR, and health-related quality of life assessed by the European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire Core 30.

The primary objective of the SC cohort of GO29781 was pharmacokinetic non-inferiority of the SC formulation of mosunetuzumab compared with the IV formulation.1 Key secondary end points in this cohort included CR rate, ORR, DOR, PFS, and safety and tolerability.

In terms of safety, the most common any-grade AEs were injection site reactions (60.6%), fatigue (35.1%), and cytokine release syndrome (CRS; 29.8%). The severity of CRS was low, with 27.7% of events being grade 1 to 2 and 2.1% being grade 3. Most instances of CRS occurred during cycle 1 and fully resolved in a median time of 2 days (range, 1-15).

SC mosunetuzumab has the potential to reduce treatment administration time with an injection time of approximately 1 minute, compared with 2 to 4 hours for IV infusion. The agent is designed to be administered for a fixed duration of approximately 6 to 12 months, depending on a patient’s response to treatment; it can also be given in the outpatient setting. Results from GO29781 have been submitted to other global health authorities beyond the EMA for approval, including the FDA, according to the news release.

References

1. CHMP recommends EU approval of Roche’s subcutaneous formulation of Lunsumio for people with relapsed or refractory follicular lymphoma. News release. Roche. September 18, 2025. Accessed September 19, 2025. https://www.roche.com/media/releases/med-cor-2025-09-19
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 September 19, 2025. https://clinicaltrials.gov/study/NCT02500407