WHO backs three experimental drugs for Bundibugyo Ebola outbreak

AFRICA—The World Health Organization (WHO) has identified three experimental treatments as top priorities for clinical evaluation in response to the ongoing Bundibugyo strain Ebola outbreak affecting the Democratic Republic of the Congo (DRC) and Uganda.

The agency has recommended Mapp Biopharmaceutical’s MBP134 antibody therapy, Regeneron’s monoclonal antibody, maftivimab, and Gilead Sciences’ antiviral, remdesivir, for immediate study in clinical trials to assess their safety and effectiveness against the rare Ebola strain.

WHO announced the recommendations after convening several technical advisory groups and outside experts to review available treatment and vaccine candidates.

The agency emphasized that all proposed therapies and vaccines should only be used within ethically approved clinical trials to generate reliable scientific data.

Outbreak escalates across the region

The latest recommendations come as health authorities continue to battle a widening outbreak in eastern DRC, with additional confirmed cases reported in Uganda.

WHO recently declared the outbreak a Public Health Emergency of International Concern (PHEIC), citing concerns over regional spread, insecurity in affected areas, and the absence of approved medical countermeasures for the Bundibugyo virus.

Unlike the more common Zaire strain of Ebola, the Bundibugyo variant currently has no licensed vaccine or targeted treatment.

Health officials say the outbreak has already resulted in hundreds of suspected infections and deaths, while surveillance teams continue contact tracing and case investigations across affected communities.

WHO said the experimental therapies demonstrated encouraging results in preclinical studies and animal models, prompting experts to prioritize them for urgent clinical assessment.

Regeneron expands support for Ebola response

Regeneron confirmed this week that supplies of maftivimab are already available in the DRC and could be deployed immediately for investigational treatment programs or integrated into ongoing research efforts.

The company noted that maftivimab, one of the antibodies in its FDA-approved Ebola therapy, Inmazeb, has shown broad neutralizing activity against several Ebola species, including the Bundibugyo strain.

WHO advisors also recommended evaluating combination therapy involving monoclonal antibodies and remdesivir, a strategy researchers believe could improve treatment outcomes for infected patients.

Meanwhile, Reuters reported that U.S. authorities are also collaborating with Mapp Biopharmaceutical and other partners to accelerate development and possible deployment of MBP134 during the current outbreak response.

Vaccine candidates move toward clinical trials

On the vaccine front, WHO identified the single-dose rVSV Bundibugyo vaccine, developed by the International AIDS Vaccine Initiative (IAVI), as the most promising candidate currently under development.

However, the vaccine is not expected to be ready for human efficacy trials for another seven to nine months.

Another candidate vaccine, ChAdOx1 Bundibugyo, developed by Oxford University in partnership with the Serum Institute of India, could enter clinical testing within two to three months if additional animal study data confirm its potential effectiveness.

WHO also reviewed the possible use of Merck’s Ervebo, currently the only licensed Ebola vaccine globally.

However, experts advised against deploying the vaccine outside research settings because evidence showing protection against the Bundibugyo strain remains limited and inconclusive.

Focus on prevention and clinical research

In addition to treatment efforts, the WHO highlighted Gilead’s experimental oral antiviral obeldesivir as a priority option for post-exposure prevention among contacts of confirmed Ebola cases.

The agency said the drug’s effectiveness will depend heavily on the rapid identification of cases and on robust contact tracing systems in affected regions.

WHO is currently working with authorities in the DRC and Uganda, alongside partners including Africa CDC and international research organizations, to design and implement clinical trials under strict ethical and scientific standards.

Health officials are also strengthening surveillance, laboratory testing, cross-border coordination, and community engagement as they attempt to contain further spread of the virus across the region.