Sabin Launches U.S. Phase 2 Trial of Marburg Vaccine

The Sabin Vaccine Institute has launched a Phase 2 clinical trial of its Marburg vaccine candidate in the United States, with the first doses administered this week in Melbourne, Florida.

The trial expands on Sabin’s ongoing Phase 2 research in Kenya and Uganda. Initial data from those African sites are expected in the coming months.

The U.S. trial will enroll 200 adult volunteers, ages 18 to 70, across four locations: Melbourne; Dallas, Texas; Huntsville, Alabama; and Peoria, Illinois. The randomized, placebo-controlled, double-blind study will evaluate the vaccine’s safety and immune response, monitoring participants for one year.

Sabin’s clinical efforts come amid a rising frequency of Marburg virus outbreaks, intensifying global demand for a licensed vaccine.

In 2024, the Sabin Vaccine Institute supported an open-label Phase 2 trial in Rwanda during a Marburg outbreak by supplying the investigational vaccine. The trial, sponsored by the Rwanda Biomedical Centre, vaccinated more than 1,700 people — primarily frontline health workers — with first doses delivered within nine days of the outbreak’s declaration. Rwanda’s outbreak ended Dec. 20 with a case fatality rate of 23%, below the historical average of about 50%. Factors such as rapid detection, better surveillance and timely care contributed to the lower death rate.

Another Marburg outbreak was declared in Tanzania on Jan. 20 and ended on March 13.

There are currently no approved vaccines for Marburg virus disease, a highly virulent illness caused by a filovirus in the same family as Ebola. It spreads through direct contact with the blood or bodily fluids of infected individuals and causes severe hemorrhagic fever.

“Recent outbreaks highlight the urgent need to strengthen our defenses against this deadly and unforgiving disease,” said Amy Finan, Sabin’s chief executive officer. “Sabin’s Phase 2 clinical trials will generate essential data to move this vaccine closer to licensure — and offer a potentially life-saving tool where none exists.”

Sabin’s single-dose Marburg vaccine candidate, based on the cAd3 platform, showed promise in Phase 1 and preclinical studies, producing rapid and robust immune responses while demonstrating safety.

“Conducting clinical trials in Africa is key to evaluating the vaccine in regions where Marburg and other filoviruses are most common or endemic,” said Kelly Warfield, Sabin’s president of research and development. “The U.S. trial will give us vital safety and immune response data for non-endemic populations, helping us better prepare for outbreaks and spread of this disease.”

The trials are funded by the Biomedical Advanced Research and Development Authority (BARDA), part of the U.S. Department of Health and Human Services. Sabin and BARDA began collaborating in 2019 to develop vaccine candidates for Marburg and Sudan viruses. To date, Sabin has received approximately $252 million in BARDA funding under multi-year contracts to support vaccine development.

A separate Phase 2 trial of Sabin’s Sudan virus vaccine is underway in Uganda and Kenya. A U.S. trial for the Sudan candidate is scheduled to begin later this year.