First results from a small Phase I trial published in the New England Journal of Medicine show that an Ebola vaccine being developed by GlaxoSmithKline and the National Institutes of Health was well-tolerated and produced an immunological response in each of the 20 healthy adult volunteers in the USA who received it.

The vaccine uses a type of chimpanzee cold virus as a carrier to deliver genetic material from the Sudan and the Zaire strains of the Ebola virus, which is responsible for the current outbreak in west Africa. GSK has been working with the NIH to accelerate development of both this and a monovalent version targeting only the Zaire strain in response to the current Ebola epidemic.

‘First piece in jigsaw’

Moncef Slaoui, chairman of vaccines at GSK said: “We are very encouraged by these positive first trial results”, but added that “it’s important to remember that these data are the first piece in the jigsaw and we’re continuing to gather other important information”. He added that over the coming weeks, “we will see results from further Phase I trials which will tell us more about the profile of the monovalent vaccine; most significantly results from a trial in Mali which is assessing its safety and immune response in west African populations”.

If the combined data are positive, trials will begin in early 2015 “to see whether the immune response we are seeing in Phase I actually translates into providing people in affected countries with meaningful protection against Ebola”, Dr Slaoui noted. Then, Phase III trials will involve “the vaccination of thousands of volunteers, including frontline healthcare workers in affected countries, including Liberia and Sierra Leone, and possibly Guinea”.

GSK added that it will continue to actively explore “with relevant organisations and partners all opportunities to accelerate the development of manufacturing at an industrial scale”. Additionally, the company is looking at whether use of a booster vaccine may help provide longer-lasting protection.