Regeneron Pharmaceuticals, Inc.

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Bullish +75

Regeneron’s Ebola Antibody Recommended by World Health Organization for Investigational Use in Response to Current Bundibugyo Ebolavirus Outbreak

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🏥 Regeneron's maftivimab antibody has been recommended by the WHO Therapeutics Advisory Group for evaluation against the current Bundibugyo ebolavirus outbreak.

🌍 The recommendation follows a WHO declaration that the Bundibugyo outbreak in the Democratic Republic of the Congo and Uganda constitutes a public health emergency of international concern.

💉 Maftivimab is the most potent neutralizing component of Inmazeb, which was the first Ebola treatment approved by the U.S. FDA for Zaire ebolavirus.

🔬 While Inmazeb is approved for Zaire ebolavirus, maftivimab has demonstrated broad in vitro activity against multiple Ebola species, including Bundibugyo.

📋 The WHO is working with governments in DRC and Uganda to facilitate clinical trials of prioritized investigational treatments for the current outbreak.

🤝 Regeneron CEO Leonard Schleifer stated the company is coordinating with the U.S. Department of Health and Human Services and global health organizations.

💰 Since 2018, Inmazeb has been provided at no cost under a compassionate use protocol to patients in countries experiencing Zaire ebolavirus outbreaks.

📦 Regeneron donated 500 doses of Inmazeb to the WHO in September 2025 for exclusive use by low- and lower-middle income countries at risk for Ebola.

🚀 The company is preparing its existing supply of maftivimab for potential upcoming clinical trials as quickly as possible.

📍 Supply of Inmazeb is already on the ground in the DRC, available for immediate treatment or as an additional component of the study.

🛡️ Regeneron is supporting the Afya Foundation's emergency response efforts to safeguard frontline healthcare workers during the outbreak.

🧬 Inmazeb was created using Regeneron's VelocImmune platform and consists of three monoclonal antibodies that neutralize the Ebola virus.

✅ The safety and efficacy of Inmazeb were established through the 681-patient PALM Trial conducted during the 2018 DRC outbreak.

📉 The PALM Trial was stopped early in 2019 after showing Inmazeb's superiority in preventing death compared to other investigational treatments.

📜 Inmazeb received FDA approval in 2020 and is indicated for adult and pediatric patients, including neonates born to infected mothers.

🌐 WHO published its first guidelines for Ebola virus therapeutics in 2022, which strongly recommend the use of Inmazeb.

Bullish Signals
  • Regeneron's maftivimab has been recommended by the World Health Organization's Therapeutics Advisory Group to be prioritized for evaluation in clinical trials for the current Bundibugyo ebolavirus outbreak.
  • Maftivimab is the most potent neutralizing antibody in Inmazeb and has demonstrated broad activity in vitro against multiple Ebola species, including the Bundibugyo virus.
  • Inmazeb was the first Ebola treatment approved by the U.S. FDA and has been administered to hundreds of patients with an acceptable safety profile.
  • Regeneron donated 500 doses of Inmazeb to the WHO in September 2025 for exclusive use by governments of low- and lower-middle income countries at-risk for Ebola outbreaks.
  • The company's PALM Trial, involving 681 patients, showed the superiority of Inmazeb in preventing death versus two other investigational treatments, leading to early trial termination in 2019.
  • Inmazeb is approved by the FDA for adult and pediatric patients, including neonates born to infected mothers, demonstrating broad applicability across patient demographics.
  • Regeneron has a track record of rapidly delivering medical solutions during global health crises, such as the COVID-19 pandemic and multiple Ebola outbreaks.
  • The company is working quickly to prepare existing supply of maftivimab for potential upcoming clinical trials while maintaining supply on the ground in the DRC.
Risk Factors
  • Maftivimab has not yet been tested in vivo as a monotherapy against Bundibugyo ebolavirus, despite being recommended for study.
  • The current clinical trial is investigational and requires independent execution by local governments in the DRC and Uganda, introducing potential delays or logistical hurdles.
  • Inmazeb is currently approved only for Orthoebolavirus zairense (Zaire ebolavirus), not specifically for Bundibugyo ebolavirus, limiting its immediate regulatory approval status for this new strain.
Full Analysis
Regeneron Pharmaceuticals announced on May 28, 2026, that the World Health Organization's (WHO) Therapeutics Advisory Group has recommended maftivimab for prioritized evaluation in clinical trials addressing the current Bundibugyo ebolavirus outbreak in the Democratic Republic of the Congo and Uganda. Maftivimab is the most potent neutralizing antibody component within Inmazeb, a three-antibody cocktail already approved by the U.S. FDA for treating Zaire ebolavirus. While Inmazeb treats the Zaire species, maftivimab has demonstrated broad in vitro activity against multiple Ebola species, including Bundibugyo, though it has not yet been tested as a monotherapy against this specific strain in vivo. The WHO declared the current outbreak a public health emergency of international concern and is collaborating with local governments to facilitate research evaluations for prioritized products like Regeneron's antibody. The company stated it is coordinating efforts with the U.S. Department of Health and Human Services and leveraging its history of rapid response during crises like COVID-19 and previous Ebola outbreaks. Inmazeb, approved by the FDA in 2020, was developed using the VelocImmune platform and consists of three monoclonal antibodies designed to neutralize the virus and support immune cells. Its efficacy and safety were established through the 681-patient PALM Trial during the 2018 DRC outbreak, which showed superiority over other investigational treatments, leading to early termination in 2019. Since approval, Inmazeb has been available under compassionate use protocols for free in affected countries including the DRC and Guinea since 2018. In September 2025, Regeneron donated 500 doses of Inmazeb specifically for low- and lower-middle income countries at risk for outbreaks and also delivered a stockpile to the U.S. Government for national preparedness. Regeneron is currently preparing its existing supply of maftivimab for potential upcoming clinical trials, while maintaining that a full supply of Inmazeb remains on the ground in the DRC should WHO wish to utilize it for immediate treatment or as an additional component of the study. Additionally, the company is supporting Afya Foundation's emergency response efforts aimed at safeguarding frontline healthcare workers and strengthening healthcare system resilience during the outbreak.