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Inmazeb® (a three-antibody cocktail consisting of maftivimab, atoltivimab and odesivimab-ebgn) was the first Ebola treatment approved by the U.S. Food and Drug Administration, indicated specifically for the Orthoebolavirus zairense species, and has been administered to hundreds of patients
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Maftivimab, the most potent neutralizing antibody in Inmazeb, has shown broad activity in vitro against multiple Ebola species, including Bundibugyo
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Maftivimab has been recommended to be studied as a monotherapy in the current outbreak
TARRYTOWN, N.Y.,May 28, 2026(GLOBE NEWSWIRE) --Regeneron Pharmaceuticals, Inc.(NASDAQ: REGN) today announced that maftivimab, the most potent neutralizing antibody included in Inmazeb® (maftivimab, atoltivimab and odesivimab-ebgn), has been recommended by the World Health Organization’s (WHO)Therapeutics Advisory Groupto be prioritized for evaluation in clinical trials of investigational treatments for Bundibugyo ebolavirus. Maftivimab has demonstrated broad activity in vitro against multiple Ebola species, including Bundibugyo.
The trial pertains to the WHO’s recent declaration that the current outbreak of Ebola disease caused by Bundibugyo virus in theDemocratic Republic of the Congo(DRC) andUgandaconstitutes a public health emergency of international concern.WHOis now working closely with the governments of DRC andUgandato facilitate the implementation of research evaluations of the prioritized products.
“We are closely coordinating our efforts with theU.S. Department of Health and Human Services(HHS) and look forward to working with theWorld Health Organizationand others as clinical evaluation moves ahead,” saidLeonard S. Schleifer, M.D., Ph.D., Board co-Chair, President and Chief Executive Officer ofRegeneron. “Regeneron has a track record of rapidly delivering important medical solutions during times of global health crisis, such as the COVID-19 pandemic and multiple Ebola outbreaks, and we know that independently run and locally executed clinical trials are critical to developing effective new medicines in such situations.”
Inmazeb is already approved by theU.S. Food and Drug Administrationfor the treatment of infection caused by Orthoebolavirus zairense, also known asZaireebolavirus, in adult and pediatric patients, including neonates born to infected mothers. Maftivimab is the most potent virus-neutralizing component of Inmazeb and has demonstrated broad neutralizing activity in laboratory studies against Bundibugyo ebolavirus; it has not yet been tested in vivo as a monotherapy against this distinct Ebola virus. Maftivimab has been administered to hundreds of human patients as a component of Inmazeb, which has demonstrated an acceptable safety profile. Since 2018, Inmazeb has been offered byRegeneronat no cost under a compassionate use protocol to infected persons in countries experiencing an Orthoebolavirus zairense outbreak, including the DRC andGuinea.
“Regeneron’s prior work in Ebola has shown how innovative science and groundbreaking technology platforms can be rapidly translated into life-saving medicines for people facing some of the world’s most dangerous infectious diseases,” saidGeorge D. Yancopoulos, M.D., Ph.D., Board co-Chair, President and Chief Scientific Officer ofRegeneron. “As we advance our robust portfolio of transformative medicines, we always strive to do the right thing when patients and the world need urgent scientific action – whether that’s by collaborating with global health organizations to pursue new treatments or offering a life-changing new gene therapy for free in the United States.”
InSeptember 2025, the company donated 500 doses of Inmazeb to theWHOfor exclusive use by governments of low- and lower-middle income countries that are most at-risk for Ebola outbreaks.1 Regeneronhas also delivered a stockpile of Inmazeb to theU.S. Governmentas part of HHS’s efforts to enhance national preparedness for public health emergencies. The company is closely coordinating its response efforts with the United States Government.
Regeneronis working as quickly as possible to prepare existing supply of maftivimab for use in potential upcoming clinical trials. Supply of Inmazeb is already on the ground in the DRC, shouldWHOwish to utilize it for immediate treatment or as an additional component of the study.Regeneronis also supporting Afya Foundation’s emergency response efforts aimed at safeguarding frontline healthcare workers and strengthening healthcare system resilience during the current outbreak.
About Inmazeb
Inmazeb is approved by theU.S.FDA for the treatment of infection caused by Orthoebolavirus zairense (also known asZaire ebolavirus) in adult and pediatric patients, including neonates born to a mother who is RT-PCR positive for Orthoebolavirus zairense infection.
Inmazeb was created usingRegeneron's VelocImmune® platform and associated VelociSuite® technologies. The treatment consists of three monoclonal antibodies that help neutralize the Ebola virus by blocking its ability to invade a patient’s cells and/or enlisting other immune cells to target infected cells and remove them from the body.
The safety and efficacy of Inmazeb was established through the 681-patient PALM Trial, which was independently conducted by theWHO, theNational Institutes of Health(NIH) and the Institut National de Recherche Biomédicale (INRB) during the 2018 DRC outbreak. In 2019, as reported in theNew England Journal of Medicine, the PALM Trial was stopped early following a pre-specified interim analysis that showed the superiority of Inmazeb in preventing death versus two other investigational treatments.
Inmazeb was approved by the FDA in 2020, and in 2022,WHO published its first guidelines for Ebola virus therapeutics, which strongly recommends the use of Inmazeb for treatment ofZaire ebolavirus infection and calls on the global community to engage all possible mechanisms to improve access to life-saving Ebola medicines. Heeding this call, inNovember 2023, Inmazeb became the first and only Ebola treatment to be prequalified by theWHO, certifying that the medicine meets WHO’s standards for quality, safety and efficacy and is considered “essential.” In addition to the supply channels established in theU.S.and low- and lower-middle income countries,Regeneronhas also worked with governments in higher- and middle-income countries to establish Inmazeb stockpiles.
Inmazeb was developed in collaboration and with federal funds from BARDA, part of the Office of the Assistant Secretary for Preparedness and Response at the HHS under ongoing USG Contract Nos. HHSO100201700016C and HHSO100201500013C.
About Regeneron
Regeneron(NASDAQ: REGN) is a leading biotechnology company that invents, develops and commercializes life-transforming medicines for people with serious diseases. Founded and led by physician-scientists, our unique ability to repeatedly and consistently translate science into medicine has led to numerous approved treatments and product candidates in development, most of which were homegrown in our laboratories. Our medicines and pipeline are designed to help patients with eye diseases, allergic and inflammatory diseases, cancer, cardiovascular and metabolic diseases, neurological diseases, hematologic conditions, infectious diseases, and rare diseases.
Regeneron pushes the boundaries of scientific discovery and accelerates drug development using our proprietary technologies, such as VelociSuite®, which produces optimized fully human antibodies and new classes of bispecific antibodies. We are shaping the next frontier of medicine with data-powered insights from the Regeneron Genetics Center® and pioneering genetic medicine platforms, enabling us to identify innovative targets and complementary approaches to potentially treat or cure diseases.
1 As defined by the World Bank based on gross national income per capita.