The World Health Organization has launched a major clinical trial to evaluate two experimental Ebola treatments in the Democratic Republic of the Congo, where the latest outbreak remains concentrated in Ituri Province.
The study will assess Mapp Biopharmaceutical Inc.’s monoclonal antibody therapy MBP134 and Gilead Sciences Inc.’s antiviral drug remdesivir alongside optimized supportive care.
Structured as an adaptive platform trial, the study has been designed to continue beyond the current outbreak if necessary. Should the epidemic end before sufficient participants are enrolled, the trial will remain active and continue recruiting patients during future Ebola outbreaks to generate conclusive evidence.
Known as the Partners trial, the initiative was established in collaboration with national authorities and scientific partners in record time. “offers real hope that we can deliver concrete results for — and with — the communities at the heart of the outbreak,” WHO Director-General Tedros Adhanom Ghebreyesus said in a social media post last week.
The trial’s flexible design enables researchers to introduce or withdraw treatments as new scientific evidence becomes available. It also allows enrolment to be paused when outbreaks subside and resumed during future epidemics, enabling data to accumulate across outbreaks caused by different Ebola virus species and the related Marburg virus until definitive findings are achieved.
The current outbreak has infected nearly 1,600 people in DR Congo and neighbouring Uganda, making it the largest outbreak ever recorded involving the Bundibugyo strain of the virus. There are currently no approved vaccines or targeted treatments for this Ebola species.
Although the number of new confirmed infections has declined in recent days, health officials say transmission remains intense in Ituri Province, where treatment centres continue to face significant pressure due to rising patient numbers.
Researchers will primarily assess all-cause mortality 28 days after patients are enrolled in the study. Secondary outcomes will include the rate of viral clearance, changes in viral load, improvements in organ function and pregnancy outcomes, with expectant mothers monitored through childbirth.
The research team intends to recruit several hundred participants over time. Instead of setting a fixed enrolment target for the current outbreak, the protocol allows recruitment to continue during future epidemics if additional participants are needed to answer the study’s key scientific questions.
Eligible participants will be randomly assigned to receive MBP134 as a single-dose monoclonal antibody infusion, remdesivir administered daily for up to 10 days, a combination of both treatments, or optimised supportive care alone.
The study also includes children, pregnant women and breastfeeding mothers, reflecting efforts to ensure populations historically excluded from outbreak research are represented despite facing some of the highest risks of death from Ebola.
MBP134 has demonstrated broad effectiveness against multiple Ebola virus species in laboratory and animal studies, including the Bundibugyo strain, although its use in humans remains limited. Remdesivir, marketed as Veklury, has shown broad antiviral activity against filoviruses in laboratory testing and has extensive safety data from the COVID-19 pandemic. However, its effectiveness against Ebola remains uncertain following earlier studies involving the Zaire Ebola strain.
University of Oxford is serving as the trial’s central coordinating office, while the WHO is sponsoring the study. Kinshasa-based physician-scientist Placide Mbala Kingebeni is leading the trial nationally.
The study begins as health authorities face growing operational challenges beyond the outbreak itself. Recent reports from the National Institute of Public Health indicate that response teams have come under attack, Ebola infrastructure has been vandalised and persistent insecurity continues to disrupt field operations. Over the weekend, an infection-prevention team carrying out decontamination work in North Kivu was attacked, with its vehicle stoned.
Authorities have also reported continued challenges with contact tracing, resistance from some communities toward screening and treatment efforts, and overcrowding at Ebola treatment centres.
Despite these obstacles, the response effort is expanding. New diagnostic laboratories have been established closer to outbreak hotspots, additional treatment facilities are under construction, and free healthcare services have been introduced in several of the worst-affected communities to encourage people to seek medical attention earlier.
