Regeneron Gains WHO Advisory Backing for Maftivimab Trials in Bundibugyo Ebolavirus Outbreak

Investigational use frameworks and emergency supply chains are now in focus for Regeneron Pharmaceuticals, after the WHO Therapeutics Advisory Group recommended maftivimab be prioritized for clinical evaluation in the active Bundibugyo ebolavirus outbreak spanning the Democratic Republic of the Congo and Uganda, a situation the WHO has declared a public health emergency of international concern.

Maftivimab is the primary virus-neutralizing component of Inmazeb (maftivimab, atoltivimab and odesivimab-ebgn), the first Ebola treatment approved by the U.S. Food and Drug Administration under 21 CFR frameworks for Orthoebolavirus zairense. In vitro data show broad neutralizing activity against multiple Ebola species, including Bundibugyo; however, maftivimab has not yet been evaluated as a monotherapy in vivo against this distinct viral species. The WHO recommendation positions it as a monotherapy candidate for the current outbreak trials, a meaningful regulatory and clinical distinction from its approved combination indication.

For regulatory affairs leads, the pathway here is investigational rather than label-extension: WHO is coordinating with DRC and Uganda governments to implement locally executed research evaluations, consistent with established emergency use and compassionate access precedents. Regeneron has confirmed active coordination with the U.S. Department of Health and Human Services, signaling that federal preparedness infrastructure is engaged alongside multilateral channels.

Supply readiness context is relevant. In September 2025, Regeneron donated 500 doses of Inmazeb to the WHO for exclusive use by at-risk low- and lower-middle income country governments. A separate Inmazeb stockpile has been delivered to the U.S. Government as part of HHS national preparedness efforts. Since 2018, Inmazeb has been offered at no cost under compassionate use to patients in countries experiencing Orthoebolavirus zairense outbreaks, including the DRC and Guinea, providing an existing logistics and distribution baseline that may inform maftivimab monotherapy supply planning for the current response.

The safety profile of maftivimab as a component of Inmazeb has been established across hundreds of administered patients, a data point that will likely anchor the investigational trial design and inform any expedited review submissions to participating national regulatory authorities.

The pace at which WHO and partner governments formalize trial protocols will determine whether maftivimab monotherapy generates in vivo efficacy data before the current outbreak is contained.

Source: Regeneron Pharmaceuticals via GlobeNewswire, 28 May 2026.