Merck & Co. Inc. reports that its investigational Ebola vaccine candidate, rVSV-ZEBOV, was found to have 100% efficacy in an analysis of interim data from a Phase III ring vaccination trial in Guinea.

To date, more than 4,000 participants have received the vaccine in this innovative trial, called “Ebola ça suffit” or “Ebola, that's enough.” The trial was conducted by a team that included researchers from the World Health Organization (WHO), the Norwegian Institute of Public Health, the Health Ministry of Guinea and Médecins sans Frontières, among others. The results from this continuing study, as well as other studies already underway and additional studies to be conducted, will be used to support worldwide regulatory submissions.

The rVSV-ZEBOV vaccine was initially engineered with support from the Public Health Agency of Canada and was licensed to NewLink Genetics Corporation. To make the vaccine, the vesicular stomatitis virus was weakened by removing one of its genes, which was then replaced with a single Ebola virus gene that cannot cause disease by itself. Vaccinated individuals have been shown to develop antibodies against the Ebola virus, which could help protect against future infection. The significance and durability of this immune response have not been determined.

In late 2014, when the current Ebola outbreak was at its most severe, Merck licensed rVSV-ZEBOV from NewLink Genetics, with the goal of accelerating the assessment of this candidate vaccine. Since that time, Merck has helped to enable a broad development program, including the interim Phase III efficacy results. To date, the rVSV-ZEBOV vaccine has been administered to more than 9,000 people in Phase I, II, and III clinical trials.

In addition to NewLink and the Public Health Agency of Canada, global and national health organizations, including the National Institute of Allergy and Infectious Diseases (NIAID), the Walter Reed Army Institute of Research (WRAIR), the Canadian Immunization Research Network (CIRN), and the US Army Medical Research Institute of Infectious Diseases (USAMRIID) have helped to conduct studies of the rVSV-ZEBOV vaccine. Major funders for these studies included the US Department of Defense's (DoD) Defense Threat Reduction Agency (DTRA) and Joint Vaccine Acquisition Program (JVAP), the US Department of Health and Human Service's Biomedical Advanced Research Development Authority (BARDA), the National Institutes of Health (NIH), and the Wellcome Trust. In addition to the Phase III trial in Guinea e, other studies evaluating the rVSV-ZEBOV vaccine are being conducted in Sierra Leone and Liberia. Merck is responsible for research, development and manufacturing efforts in support of the rVSV-ZEBOV vaccine.

Source: Merck & Co.