Mosunetuzumab, sold under the brand name Lunsumio, is a

monoclonal antibody A monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a cell lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Monoclonal antibodie ...

used for the treatment of

follicular lymphoma Follicular lymphoma (FL) is a cancer that involves certain types of white blood cells known as lymphocytes. This cancer is a form of Non-Hodgkin Lymphoma and it originates from the uncontrolled division of specific types of B-cells ( centrocytes ...

. It bispecifically binds CD20 and CD3 to engage T-cells. It was developed by

Genentech Genentech, Inc. is an American biotechnology corporation headquartered in South San Francisco, California. It operates as an independent subsidiary of holding company Roche. Genentech Research and Early Development operates as an independent cent ...

. The most common adverse reactions (≥20%) include

cytokine release syndrome In immunology, cytokine release syndrome (CRS) is a form of systemic inflammatory response syndrome (SIRS) that can be triggered by a variety of factors such as infections and certain drugs. It refers to cytokine storm syndromes (CSS) and occur ...

, fatigue, rash, pyrexia, and headache. The most common grade 3 to 4 laboratory abnormalities (≥10%) include decreased lymphocyte count, decreased phosphate, increased glucose, decreased neutrophil count, increased uric acid, decreased white blood cell count, decreased hemoglobin, and decreased platelets. Mosunetuzumab was approved for medical use in the European Union in June 2022, and in the United States in December 2022. The US

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

(FDA) considers it to be a

first-in-class medication A first-in-class medication is a prototype drug that uses a "new and unique mechanism of action" to treat a particular medical condition. While the Food and Drug Administration's Center for Drug Evaluation and Research tracks first-in-class medic ...

Medical uses

Mosunetuzumab is

indicated In medicine, an indication is a valid reason to use a certain test, medication, procedure, or surgery. There can be multiple indications to use a procedure or medication. An indication can commonly be confused with the term diagnosis. A diagnosis ...

for the treatment of adults with relapsed or refractory follicular lymphoma after two or more lines of systemic therapy.

Contraindications

The prescribing information for mosunetuzumab in the US has a

boxed warning In the United States, a boxed warning (sometimes "black box warning", colloquially) is a type of warning that appears near the beginning of the package insert for certain prescription drugs, so called because the U.S. Food and Drug Administratio ...

for serious or life-threatening cytokine release syndrome.

History

Mosunetuzumab-axgb was evaluated in GO29781 (NCT02500407), an open-label, multicenter, multi-cohort study. 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. The US

(FDA) granted the application for mosunetuzumab

priority review Priority review is a program of the United States Food and Drug Administration (FDA) to expedite the review process for drugs that are expected to have a particularly great impact on the treatment of a disease. The priority review voucher program ...

breakthrough therapy Breakthrough therapy is a United States Food and Drug Administration designation that expedites drug development that was created by Congress under Section 902 of the 9 July 2012 Food and Drug Administration Safety and Innovation Act. The FDA's "b ...

, and

orphan drug An orphan drug is a medication, pharmaceutical agent that is developed to treat certain rare medical conditions. An orphan drug would not be profitable to produce without government assistance, due to the small population of patients affected by th ...

designations.

Society and culture

Legal status

In April 2022, the

Committee for Medicinal Products for Human Use The Committee for Medicinal Products for Human Use (CHMP), formerly known as the Committee for Proprietary Medicinal Products (CPMP), is the European Medicines Agency's committee responsible for elaborating the agency's opinions on all issues regar ...

(CHMP) of the

European Medicines Agency The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of pharmaceutical products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products ...

(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. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged. Mosunetuzumab was approved for medical use in the European Union in June 2022.

Names

Mosunetuzumab is the international nonproprietary name (INN).

Withdrawal from Swiss Market

In July 2025,

Roche F. Hoffmann-La Roche AG, commonly known as Roche (), is a Switzerland, Swiss multinational corporation, multinational holding healthcare company that operates worldwide under two divisions: Pharmaceuticals and Diagnostics. Its holding company, ...

withdrew Lunsumio from the Swiss market following failed price negotiations with the Swiss Federal Office of Public Health (BAG). 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. When

Swissmedic The Swiss Agency for Therapeutic Products (Swissmedic) is the Swiss surveillance authority for medicines and medical devices, registered in Bern. It began operations on 1 January 2002 as successor of ''Interkantonale Kontrollstelle für Heilmittel ...

extended the temporary authorization in February 2025 due to still-missing clinical data, Roche rejected the previously negotiated pricing model and demanded higher prices. The BAG refused to modify the agreement, citing concerns that exceptions would set a precedent for other pharmaceutical companies. The withdrawal was announced to oncologists on July 1, 2025, with Roche also refusing to provide individual case reimbursements—a standard Swiss mechanism for exceptional medical situations. Instead, the company offered to provide the medication free through its patient access program for hardship cases. Oncologists criticized the decision as unprecedented, while some experts suggested the withdrawal reflected broader pressures from potential U.S. pricing reforms that could affect Roche's largest market.

References

External links

* {{Portal bar , Medicine Monoclonal antibodies for tumors Orphan drugs Drugs developed by Genentech