A clinical trial of two potential treatments for the strain of Ebola driving a deadly outbreak in the Democratic Republic of the Congo began in the country on Thursday, the World Health Organization said, according to CIDRAP and AFP.

The trial is evaluating the monoclonal antibody MBP134, developed by Mapp Biopharmaceutical, and the antiviral remdesivir, made by Gilead Sciences, alone and in combination, against a control group receiving the best available supportive care, CIDRAP reported. It is being run by the DRC's National Institute for Biomedical Research together with the University of Oxford and the Institute of Tropical Medicine in Antwerp, Belgium.

As of late June, the WHO had recorded 1,406 confirmed cases and 438 deaths in the DRC, with about 208 recoveries, according to WHO figures cited by CIDRAP. Neighbouring Uganda has reported roughly 20 cases and two deaths.

Why this outbreak is different

The outbreak, first reported in May 2026 in the country's northeast, is caused by the Bundibugyo species of Ebola, for which there are no licensed vaccines or treatments, according to the WHO and Doctors Without Borders. That distinguishes it from the Zaire species, against which the licensed Ervebo vaccine is directed.

The WHO's Strategic Advisory Group of Experts on Immunization has not recommended using Ervebo outside controlled research settings in this outbreak, because evidence on whether it cross-protects against Bundibugyo remains limited and inconclusive, according to WHO guidance. A WHO technical advisory group has prioritised two experimental Bundibugyo vaccine candidates — one from IAVI and one from Oxford and the Serum Institute of India — for near-term evaluation.

Why it matters

Neither MBP134 nor remdesivir has previously been tested in humans specifically against Ebola, according to CIDRAP. Two antibody treatments are already approved for the more familiar Zaire species, but none exists for Bundibugyo, leaving clinicians without a proven therapy for the current outbreak.

Vasee Moorthy, acting lead of the WHO's research and development Blueprint, cautioned that results would not come quickly. "We shouldn't expect that this is going to be over in weeks, it will take some months," he said, adding that the trial could ultimately enrol around a thousand patients, according to CIDRAP.

What to watch

Open questions include whether case numbers stabilise across the affected provinces of Ituri, North Kivu and South Kivu, and whether the trial can enrol enough patients to yield reliable results while the outbreak is still active; Moorthy said that could take months. Progress on the two prioritised vaccine candidates will also be closely followed, as a licensed Bundibugyo vaccine could change how future outbreaks of the strain are contained.