WHO recommends Regeneron’s maftivimab for Bundibugyo Ebola trials, marking a milestone in expanding treatment options beyond Zaire ebolavirus.
Written By: Kalyani Boharapi,
M. Pharm (Reg. Affairs)
Reviewed By: Pharmacally Editorial Team
Regeneron Pharmaceuticals has achieved a key milestone as the World Health Organization (WHO) recommended maftivimab for priority evaluation in clinical trials targeting Bundibugyo ebolavirus, the strain driving the current outbreak in the Democratic Republic of the Congo (DRC) and Uganda. The move, announced alongside WHO’s declaration of a public health emergency of international concern, underscores the urgent need for therapeutics beyond Zaire ebolavirus.
Scientific Rationale
Maftivimab is the most potent neutralizing antibody within Inmazeb® (maftivimab, atoltivimab, odesivimab-ebgn), the first FDA-approved treatment for Ebola virus disease caused by Orthoebolavirus zairense. While Inmazeb is approved specifically for Zaire ebolavirus, laboratory studies have demonstrated maftivimab’s broad neutralizing activity against other Ebola species, including Bundibugyo. The antibody has not yet been evaluated as a standalone therapy in clinical studies for Bundibugyo infection.
WHO Process and Trial Design
The recommendation forms part of WHO’s R&D Blueprint mechanism, which prioritizes investigational countermeasures during outbreaks. Planned evaluations are expected to follow WHO’s Master Protocol framework, enabling standardized trial design across multiple sites. Bundibugyo ebolavirus, first identified in Uganda in 2007, remains without an approved therapeutic option, making this initiative an important step toward strengthening outbreak preparedness and response.
Clinical Readiness and Supply
Regeneron is coordinating with global health agencies and the U.S. Department of Health and Human Services to support trial implementation. The company confirmed that existing Inmazeb inventory is available in the DRC and that supplies of maftivimab are being prepared for potential use. Inmazeb is also stockpiled under U.S. government contracts, supporting rapid deployment during public health emergencies.
Ebola Program Legacy
Developed using Regeneron’s VelocImmune® platform, Inmazeb combines three monoclonal antibodies that block viral entry and promote clearance of infected cells. Its efficacy was established in the 681-patient PALM trial (NCT03719586) during the 2018 DRC outbreak.
The study was stopped early after a prespecified interim analysis showed significantly lower mortality with Inmazeb than with competing investigational therapies, helping establish the treatment as a standard of care for Zaire ebolavirus infection.
Global Health Impact
Regeneron executives emphasized the importance of rapidly generating clinical evidence during infectious disease emergencies, citing prior experience with Ebola and COVID-19. Positive trial data could establish maftivimab as a targeted therapy for Bundibugyo ebolavirus and support broader research into treatments for other non-Zaire Ebola species.
The WHO recommendation opens a new development path that could strengthen global preparedness against future Ebola outbreaks.
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About the Writer
Kalyani Boharapi (LinkedIn) is a pharmacy professional and healthcare writer currently pursuing an M.Pharm in Regulatory Affairs at Dr. D. Y. Patil College of Pharmacy, with interests in pharmaceutical regulations, drug development, and healthcare innovation. She has academic exposure to dossier preparation, scientific writing, and regulatory documentation. Kalyani has also completed certification courses in Generative AI, AI in Pharma, and Bioinformatics, and actively participates in pharmaceutical conferences to stay updated with emerging trends and advancements in the healthcare and pharmaceutical industry.