Regeneron Pharmaceuticals, Inc. 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 Therapeutics Advisory Group to 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 World Health Organization?s recent declaration that the current outbreak of Ebola disease caused by Bundibugyo virus in the Democratic Republic of the Congo and Uganda constitutes a public health emergency of international concern.

Inmazeb is already approved by the U.S. Food and Drug Administration for the treatment of infection caused by Orthoebolavirus zairense, also known as Zaire ebolavirus, 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 by Regeneron at no cost under a compassionate use protocol to infected persons in countries experiencing an Orthoebolavirus zairense outbreak, including the Democratic Republic of the Congo and Guinea. In September 2025, the company donated 500 doses of Inmazeb to the World Health Organization for exclusive use by governments of low- and lower-middle income countries that are most at-risk for Ebola outbreaks. Regeneron has also delivered a stockpile of Inmazeb to the U.S. Government as part of the Department of Health and Human Services?s efforts to enhance national preparedness for public health emergencies.

Regeneron is 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 Democratic Republic of the Congo, should the World Health Organization wish to utilize it for immediate treatment or as an additional component of the study. Regeneron is also supporting Afya Foundation?s emergency response efforts aimed at safeguarding frontline healthcare workers and strengthening healthcare system resilience during the current outbreak.

Inmazeb is approved by the U.S. Food and Drug Administration for the treatment of infection caused by Orthoebolavirus zairense (also known as Zaire ebolavirus) in adult and pediatric patients, including neonates born to a mother who is RT-PCR positive for Orthoebolavirus zairense infection. Inmazeb was created using Regeneron'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 the World Health Organization, the National Institutes of Health and the Institut National de Recherche Biomédicale during the 2018 Democratic Republic of the Congo outbreak. In 2019, as reported in the New 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 Food and Drug Administration in 2020, and in 2022, the World Health Organization published its first guidelines for Ebola virus therapeutics, which strongly recommends the use of Inmazeb for treatment of Zaire ebolavirus infection and calls on the global community to engage all possible mechanisms to improve access to life-saving Ebola medicines.

In November 2023, Inmazeb became the first and only Ebola treatment to be prequalified by the World Health Organization, certifying that the medicine meets World Health Organization?s standards for quality, safety and efficacy and is considered ?essential.? In addition to the supply channels established in the United States and low- and lower-middle income countries, Regeneron has also worked with governments in higher- and middle-income countries to establish Inmazeb stockpiles.