Mosunetuzumab, sold under the brand name Lunsumio, is a monoclonal antibody used for the treatment of follicular lymphoma.[1][2] It bispecifically binds CD20 and CD3 to engage T-cells.[1][2] It was developed by Genentech.[4]
The most common adverse reactions (≥20%) include cytokine release syndrome, fatigue, rash, pyrexia, and headache.[2][3]
Mosunetuzumab was approved for medical use in the European Union in June 2022,[3] and in the United States in December 2022.[2][5] The US Food and Drug Administration (FDA) considers it to be a first-in-class medication.[6][7]
Mosunetuzumab is indicated for the treatment of adults with relapsed or refractory follicular lymphoma after two or more lines of systemic therapy.[2][3]
The prescribing information for mosunetuzumab in the US has a boxed warning for serious or life-threatening cytokine release syndrome.[2]
Mosunetuzumab-axgb was evaluated in GO29781 (NCT02500407), an open-label, multicenter, multi-cohort study.[2] The efficacy population consisted of 90 patients with relapsed or refractory FL who had received at least two prior lines of systemic therapy, including an anti-CD20 monoclonal antibody and an alkylating agent.[2]
The US Food and Drug Administration (FDA) granted the application for mosunetuzumab priority review, breakthrough therapy, and orphan drug designations.[2]
In April 2022, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a conditional marketing authorization for mosunetuzumab under the brand name Lunsumio, intended for the treatment of relapsed or refractory follicular lymphoma. The applicant for this medicinal product is Roche Registration GmbH.[8] Mosunetuzumab was approved for medical use in the European Union in June 2022.[3][9]
Mosunetuzumab is the international nonproprietary name (INN).[10]
In July 2025, Roche withdrew Lunsumio from the Swiss market following failed price negotiations with the Swiss Federal Office of Public Health (BAG).[11] The drug had been available since February 2023 through a special "Early Access" program that allowed reimbursement before complete clinical data was available. Under this arrangement, Roche initially covered treatment costs until efficacy was demonstrated, after which the remaining therapy could exceed 100,000 Swiss francs.[11][12][13][14]
When Swissmedic extended the temporary authorization in February 2025 due to still-missing clinical data, Roche rejected the previously negotiated pricing model and demanded higher prices.[11]
