Marburg vaccine candidate deemed safe and effective in small, first-in-human study

According to results published in The Lancet this week, a Phase 1, first-in-human test of an experimental Marburg virus vaccine developed by the National Institute of Allergy and Infectious Diseases (NIAID), good safety profiles and an active immune response brought hope for the candidate’s future.

Marburg virus, or MARV, is a filovirus in the same family as the Ebola virus. It’s capable of causing a progressive and feverish illness that can rapidly lead to shock and death in large numbers of those infected. It’s thought most likely to jump from certain chronically infected bats in sub-Saharan Africa to humans, bringing with it headaches, chills, organ dysfunction, delirium, and bleeding in the gastrointestinal tract and elsewhere as it goes, among other problems. Currently, no approved vaccines or specific therapies exist to treat the disease, only supportive care.

In this study of 40 healthy adult volunteers, recipients took a single dose of either a low or higher dose of the vaccine. These recipients were enrolled at the Walter Reed Army Institute of Research Clinical Trials Center. They were monitored for adverse reactions and evaluated at regular intervals for 48 weeks to track any immune responses. On a positive note, the vaccine seemed to induce strong, long-lasting immunity to the MARV glycoprotein, with 95 percent of participants showing healthy antibody response after vaccine and 70 percent holding steady for more than 48 weeks.

The vaccine candidate is known as cAd3-Marburg and was developed at NIAID’s Vaccine Research Center. It’s based on a modified chimpanzee adenovirus, cAd3, which could no longer replicate or infect cells but hosts a glycoprotein found on the surface of MARV as a target for inducing immune responses. While this was the first test for this method on MARV, the cAd3 vaccine platform has been previously used to produce solid safety profiles among investigational Ebola virus and Sudan virus vaccines.

A single-dose vaccine for Marburg could be a massive win for areas of Africa in particular, where long-term protection could help quell outbreaks. So far, experimental vaccines have led to high efficacy and durable protection rates. As such, the possibilities presented by this testing of cAd3-Marburg have already led to plans for further trials in Ghana, Kenya, Uganda, and the United States.