Sabin Institute Starts Phase 2 Trial for Sudan Ebolavirus Vaccine

On July 15, 2024, the Sabin Vaccine Institute announced the launch of a Phase 2 clinical trial for its vaccine targeting the Sudan ebolavirus. The trial is being conducted at the Makerere University Walter Reed Project (MUWRP) in Uganda, involving healthy volunteers who will receive the single-dose vaccine. This trial is significant as there are currently no approved vaccines for this particular strain of the ebolavirus, which recently caused an outbreak.

Sudan ebolavirus is part of the filovirus family, closely related to Marburg virus and Zaire ebolavirus. The latter caused a devastating outbreak in West Africa between 2014 and 2016, resulting in 11,325 deaths. Ebolavirus disease is highly contagious, spreading through direct contact with the bodily fluids of infected individuals and causing severe hemorrhagic fever. According to the World Health Organization, the disease has a fatality rate of about 50%.

The investigational Sudan ebolavirus vaccine developed by Sabin uses the cAd3 platform, the same technology used for its Marburg vaccine candidate. Phase 1 clinical and non-clinical studies of the vaccine showed promising results, indicating it is safe and capable of eliciting a rapid and strong immune response lasting up to 12 months.

This marks the second Phase 2 clinical trial collaboration between Sabin and MUWRP, which is based in Uganda's capital, Kampala. A Phase 2 trial for a Marburg vaccine is already in progress, with initial results expected later this year. Dr. Betty Mwesigwa, deputy executive director of MUWRP, is the principal investigator for the Sudan ebolavirus vaccine trial. The trial will also enroll participants at the Kenya Medical Research Institute in Siaya, Kenya, where Dr. Videlis Nduba will serve as the principal investigator. A total of 125 volunteers from both Uganda and Kenya will take part in the trial.

Amy Finan, the CEO of Sabin, expressed optimism about the vaccine's potential to combat a life-threatening disease for which no approved treatments currently exist. She emphasized the strong safety and immunogenicity data supporting the vaccine candidate and hopes the trial will provide further evidence to advance the vaccine toward licensure.

The most recent Sudan ebolavirus outbreak occurred in Uganda in the fall of 2022, starting with six suspicious deaths in the Mubende district and ultimately resulting in 55 deaths. Sabin's vaccine was the first to arrive in Uganda during the outbreak after the World Health Organization identified it as one of three vaccines for potential use in an outbreak trial. However, the outbreak ended on January 11 before the vaccine could be deployed.

Dr. Mwesigwa of MUWRP highlighted Uganda's extensive experience with Sudan ebolavirus outbreaks, stressing the importance of developing a viable vaccine for future outbreaks. The current Phase 2 clinical trial aims to evaluate the vaccine's safety and immunogenicity in a larger group of participants through a randomized, placebo-controlled, double-blind study. This methodology ensures that neither the participants nor the researchers know who receives the actual vaccine or a placebo, reducing experimental bias.

Participants will be monitored over a year, including both younger (18-50 years) and older age groups (51-70 years). Interim results from the trial are expected next year. Sabin also plans to conduct a similar Phase 2 trial for the Sudan ebolavirus vaccine in the United States.

The Sudan ebolavirus vaccine trials are supported by the Biomedical Advanced Research and Development Authority (BARDA), under the U.S. Department of Health and Human Services. Sabin has so far received around $216 million in contract awards from BARDA for advancing vaccine research against Sudan ebolavirus and Marburg virus diseases. Since their collaboration began in September 2019, BARDA and Sabin have been working on developing monovalent vaccine candidates for these diseases.