MBP134 is a newer monoclonal antibody cocktail from Mapp Biopharmaceutical that neutralises multiple Ebola species including Bundibugyo, whereas ZMapp was effective only against Zaire ebolavirus.Source: WHO Disease Outbreak News / Mapp Biopharmaceutical

Has MBP134 been tested in humans yet?

Not yet. The WHO-sponsored trial in the current Bundibugyo outbreak is awaiting regulatory approval from the DRC and Uganda before dosing begins.Source: WHO

How effective was MBP134 in animal studies?

In non-human primate studies, MBP134 provided 100% protection when administered up to eight days after infection — a significantly wider treatment window than earlier antibody therapies. The studies covered Bundibugyo, Zaire, and Sudan ebolavirus strains.Source: Mapp Biopharmaceutical / published NHP studies

Background

MBP134 is a monoclonal antibody cocktail developed by Mapp Biopharmaceutical, a small San Diego-based biotech. It is designed to neutralise multiple ebolavirus species, including Bundibugyo, Zaire, and Sudan strains. This breadth addresses a core limitation of the licensed treatments REGN-EB3 (Inmazeb) and mAb114 (Ebanga), both validated in the 2018-2020 DRC outbreak but restricted to Zaire ebolavirus. In non-human primate studies, MBP134 provided 100% protection when administered up to eight days after infection, a significantly wider treatment window than earlier antibody therapies. Broadly neutralising antibody cocktails that span multiple ebolavirus species represent the current frontier of Filovirus therapeutics: a confirmed multi-species agent would, if licensed, allow responders to deploy a single treatment without first identifying the exact Ebola species in each outbreak.

WHO is sponsoring therapeutic and prophylactic trials in the current Bundibugyo ebolavirus outbreak affecting DRC and Uganda. The trial protocol evolved from the initial WHO expert advisory (which proposed MBP134 plus remdesivir) to a revised design using MBP134 plus REGN3479 (a Regeneron monoclonal antibody) for treatment, and obeldesivir (an oral prodrug of GS-441524) for post-exposure prophylaxis. As of WHO DON605 (29 May 2026), the trial had not dosed a single patient; regulatory applications to both governments had been pending since 20 May .

The trial became the first authorised therapeutic intervention in the outbreak on 16 June 2026, weeks after the first cases were reported . The delay reflects a structural countermeasure gap: there is no licensed treatment or vaccine for Bundibugyo ebolavirus. All available licensed Ebola products, Inmazeb (REGN-EB3), Ebanga (mAb114) and Ervebo, were developed exclusively against Zaire ebolavirus during the 2018-2020 DRC outbreak. MBP134's cross-species design addresses this gap; in non-human primate studies it provided 100% protection up to 8 days post-infection .

The trial dosed its first patient on 2 July 2026 after DRC and Uganda regulators cleared the protocol , ending the six weeks the drugs sat pending signoff. By WHO's DON612 (3 July 2026), the outbreak had reached 1,481 confirmed cases and 454 deaths, with patient isolation near 44 percent, still well below the 70 percent threshold the CDC model treats as the point of collapse . A ChAdOx-platform Bundibugyo vaccine candidate remained several months from trial dosing as of late May; a second rVSV-platform candidate sat further behind. Neither has human safety data.