Sabin Vaccine Institute Begins Phase 2 Clinical Trial for Sudan Ebolavirus Vaccine

Lab technicians at Makerere University Walter Reed Project in Kampala, Uganda, analyze blood samples from clinical trial volunteers, December 18, 2023.
Lab technicians at Makerere University Walter Reed Project in Kampala, Uganda, analyze blood samples from clinical trial volunteers, December 18, 2023.

Sabin Vaccine Institute launched a Phase 2 clinical trial for its vaccine against Sudan ebolavirus, with healthy volunteers receiving the single-dose vaccine at Makerere University Walter Reed Project (MUWRP) in Uganda. There are currently no approved vaccines for this strain of ebolavirus, which saw an outbreak end just last year. Ebolavirus disease kills on average half the people infected, according to the World Health Organization.

Sudan ebolavirus is a filovirus, in the same family as Marburg virus disease and Zaire ebolavirus, which killed 11,325 in one outbreak in West Africa from 2014-16. Ebolavirus disease spreads between people via direct contact with the blood or other bodily fluids of infected people and is highly virulent, causing hemorrhagic fever.

Based on the same cAd3 platform as its Marburg vaccine candidate, Sabin’s single-dose investigational Sudan ebolavirus vaccine was found to be promising in Phase 1 clinical and non-clinical studies, with results showing it to be safe, while eliciting rapid and robust immune responses that lasted up to 12 months.

This is Sabin’s second Phase 2 clinical trial partnership with MUWRP, based in Uganda’s capital, Kampala. A Phase 2 trial for a Marburg vaccine is already underway, having recently completed enrollment. Initial results from the Marburg trial are expected later this year.

Dr. Betty Mwesigwa, deputy executive director of MUWRP, is once again the principal investigator (PI) for the Sabin-sponsored trial for the Sudan ebolavirus vaccine. In the coming weeks, participants will also be enrolled at the Kenya Medical Research Institute in Siaya, Kenya, with Dr. Videlis Nduba serving as PI for that site. In all, 125 volunteers will participate in the trial across the two countries.

“We are delighted to advance a vaccine candidate that can thwart a deadly and devastating disease, especially one that caused a fairly recent outbreak and for which no approved treatments exist,” says Amy Finan, Sabin’s Chief Executive Officer. “Sabin’s vaccine candidate is backed by strong safety and immunogenicity data, and we hope this trial will yield further evidence to move the vaccine closer to licensure.”

The most recent outbreak of Sudan ebolavirus occurred in the fall of 2022 in Uganda, after six suspicious deaths in the Mubende district. That outbreak ultimately resulted in 55 deaths. Sabin’s vaccine was the first to arrive in Uganda during that outbreak after the World Health Organization included it as one of three vaccines for possible use in an outbreak trial. The outbreak ended on January 11, prior to vaccine being deployed for use.

“Makerere University Walter Reed Project is pleased to partner with the Sabin Vaccine Institute once again,” says Dr. Mwesigwa. “Uganda has the most experience with Sudan ebolavirus outbreaks so we understand the importance of testing and researching an effective Sudan ebolavirus vaccine that could be used in the event of an outbreak.”

The Phase 2 clinical trial will evaluate safety and immunogenicity for the vaccine among a larger group of individuals than in previous trials. This is a randomized, placebo-controlled, double-blind study, meaning that neither the participants nor the researchers will know whether trial participants receive a vaccine dose or a placebo dose until after the trial is over, an approach used to help reduce experimental bias.

Participants in the clinical trial will be monitored for a full year and will include both younger (18-50 years) and older age groups (51-70 years). Interim results are expected next year. In addition to the current trial in Uganda and Kenya, Sabin plans to conduct a similar Phase 2 clinical trial for Sudan ebolavirus vaccine in the U.S.

The Sudan ebolavirus vaccine trials are supported by the Biomedical Advanced Research and Development Authority (BARDA), part of the Administration for Strategic Preparedness and Response within the U.S. Department of Health and Human Services, under multi-year contracts between the organizations.

To date, Sabin has received around $216 million in contract awards from BARDA for furthering vaccine research and development against Sudan ebolavirus and Marburg virus diseases. BARDA and Sabin began working together in September 2019 to develop the two monovalent vaccine candidates.

This project has been supported in whole or in part with federal funds from the Department of Health and Human Services; Administration for Strategic Preparedness and Response; Biomedical Advanced Research and Development Authority (BARDA), under contract numbers 75A50119C00055 and 75A50123C00010.

About the Sabin Vaccine Institute

The Sabin Vaccine Institute is a leading advocate for expanding vaccine access and uptake globally, advancing vaccine research and development, and amplifying vaccine knowledge and innovation. Unlocking the potential of vaccines through partnership, Sabin has built a robust ecosystem of funders, innovators, implementers, practitioners, policy makers and public stakeholders to advance its vision of a future free from preventable diseases. As a non-profit with three decades of experience, Sabin is committed to finding solutions that last and extending the full benefits of vaccines to all people, regardless of who they are or where they live. At Sabin, we believe in the power of vaccines to change the world. For more information, visit www.sabin.org and follow us on X, @SabinVaccine.

About Sabin’s Vaccine R&D Using the cAd3 Platform

In August 2019, Sabin announced exclusive agreements with GSK for Sabin to advance the development of the prophylactic candidate vaccines against the deadly Zaire ebolavirus, Sudan ebolavirus and Marburg virus. The three candidate vaccines were initially developed collaboratively by the U.S. National Institutes of Health and Okairos, which was acquired by GSK in 2013. The candidate vaccines, based on GSK’s proprietary cAd3 platform, were further developed by GSK, including the Phase 2 development for the Zaire ebolavirus vaccine. Under the agreements between GSK and Sabin, Sabin exclusively licensed the technology for all three candidate vaccines and acquired certain patent rights specific to these vaccines.

About the Makerere University Walter Reed Project

MUWRP is a non-profit biomedical research organization with a mission to mitigate disease threats through quality research, health care and disease surveillance. The project’s scope includes, among others; clinical research in infectious and non-infectious diseases such as HIV, Ebola, Marburg, COVID-19, Influenza and Influenza-like illnesses, and neglected tropical diseases such as Schistosomiasis, among others. A major part of the clinical research are clinical trials, where the MUWRP has conducted more than 12 phase 1 and 2 vaccine clinical trials including the first Ebola vaccine trial in Africa.