British drug-maker GlaxoSmithKline (GSK) has reported positive results from a Ebola vaccine Phase I trial, which showed that the drug was well-tolerated and produced an immunological response in each of the 20 healthy adults in the US.
The new vaccine candidate was co-developed by the National Institutes of Health’ (NIH) National Institute of Allergy and Infectious Diseases (NIAID) and Okairos, a biotechnology firm acquired by GSK in 2013.
The trial was conducted by the NIH and results were published in the New England Journal of Medicine (NEJM).
Volunteers in the trial were divided into two groups, receiving either a low or high dose and the results showed that the antibody response was stronger among those receiving the higher dose.
According to the investigators, seven of the high dose and two of the lose dose volunteers produced T-cell immune responses.
The vaccine uses a type of chimpanzee cold virus, known as chimpanzee adenovirus type 3 (ChAd3), which has been genetically designed to carry a non-infectious Ebola protein on its surface.
The bivalent vaccine is aimed at providing protection against two strains of the Ebola virus, Sudan and Zaire.
Both the parties have been jointly working to accelerate development of both bivalent version of the candidate vaccine and a monovalent version targeting only the Zaire strain in response to the current Ebola epidemic.
GSK chairman of Global Vaccines Dr Moncef Slaoui said: "It’s important to remember that these data are the first piece in the jigsaw and we’re continuing to gather other important information."
Additional data from the ongoing Phase I trials in the US, the UK, Mali and Switzerland are expected to be reported by the end of this year, which will provide more information about the profile of the monovalent vaccine.
The company said that the most significant results will come from a trial in Mali which is evaluating its safety and immune response in West African populations.
If results from these trials are positive, the next phases of the clinical trial programme will be started in early 2015 to see whether the immune response seen in Phase I actually translates into providing people in affected countries with meaningful protection against Ebola.
The trials will involve the vaccination of thousands of frontline healthcare workers in the affected African countries including Sierra Leone, Liberia and possibly Guinea.
Image: Ebola virus virion. Photo: courtesy of CDC/Cynthia Goldsmith.