The 2018–2020 Ebola outbreak in the Democratic Republic of the Congo (DRC) marked a turning point in medical history, as researchers successfully validated two life-saving treatments through a randomized controlled trial. According to the World Health Organization (WHO), patients receiving mAb114 or REGN-EB3 showed significantly higher survival rates compared to those treated with ZMapp, the previous standard of care.
How the Ebola Treatment Trial Worked
During the North Kivu and Ituri outbreak, the National Institute of Allergy and Infectious Diseases (NIAID) and the DRC’s Institut National de Recherche Biomédicale (INRB) launched the PALM trial (Pamoja Tulinde Maisha, or “Together Save Lives”). Researchers enrolled 681 patients across four treatment centers. Participants were randomly assigned to receive one of four drugs: ZMapp, remdesivir, mAb114, or REGN-EB3.
The study was designed to compare the efficacy of these monoclonal antibody therapies. These treatments work by neutralizing the virus, preventing it from entering human cells and replicating.
Why mAb114 and REGN-EB3 Replaced ZMapp
The trial was stopped early in August 2019 after an independent data safety monitoring board determined that the results were statistically conclusive. Data indicated that mortality rates were dramatically lower for patients treated with the two superior drugs.
* REGN-EB3: Developed by Regeneron Pharmaceuticals, this “cocktail” of three antibodies demonstrated a mortality rate of approximately 29%.
* mAb114: Derived from a human survivor of the 1995 Kikwit Ebola outbreak, this single-antibody treatment resulted in a mortality rate of approximately 34%.
* ZMapp: The control drug, which had been used during the 2014–2016 West Africa epidemic, showed a mortality rate of 49%.
According to the New England Journal of Medicine, the lower mortality rates for mAb114 and REGN-EB3 were even more pronounced when patients arrived at treatment centers shortly after the onset of symptoms.
Impact on Future Outbreak Response
The success of the PALM trial demonstrated that rigorous clinical research can be conducted safely and effectively even in the midst of a volatile humanitarian crisis. Before these findings, Ebola had a case fatality rate that often exceeded 50% without advanced intervention.
These treatments provide a standardized protocol for medical responders. By utilizing these monoclonal antibodies, healthcare providers can offer patients a much higher probability of recovery. The study also highlighted the importance of early detection and rapid access to care, as the effectiveness of both mAb114 and REGN-EB3 is highly dependent on how quickly they are administered after infection.
Frequently Asked Questions
What are monoclonal antibodies?
These are laboratory-made proteins that mimic the immune system’s ability to fight off harmful pathogens like viruses. In the case of Ebola, they bind to the virus and block its ability to infect healthy cells.
Are these treatments vaccines?
No. These are therapeutic treatments, not vaccines. They are designed to treat people who have already been infected with the Ebola virus, whereas vaccines are used to prevent infection before exposure occurs.
Is this treatment available for all strains of Ebola?
The trial focused specifically on the Zaire ebolavirus species, which was responsible for the 2018–2020 outbreak in the DRC. Research remains ongoing to ensure treatment efficacy across different viral variants.