Ebola Outbreak Increases Pressure to Start Vaccine Trials

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The world’s worst outbreak of Ebola has killed close to 1,100 people in West Africa and the disease could continue spreading for months, increasing pressure on researchers to accelerate the development of therapeutic interventions.

According to the British drugmaker GlaxoSmithKline, which is co-developing an Ebola vaccine together with scientists at the National Institutes of Health, a clinical trial is set to start this fall. Federal officials have said there are 400 doses available for testing in healthy adults.

GSK acquired the vaccine after buying Swiss-based biotech company Okairos last year. The experimental vaccine has already produced promising results in animal studies involving primates and, pending approval from the U.S. Food and Drug Administration, is ready to enter Phase I testing in humans.

Assuming that the drug works as well as hoped and is fast-tracked for approval, it could be ready for widespread deployment in 2015.

In the meantime, the World Health Organization, who declared last week that the Ebola outbreak was a global health emergency, has said that it is ethical to use untested drugs to treat patients infected with the virus [1]. San Diego-based Mapp Biopharmaceutical sent 12 does of an experimental drug called ZMapp to treat several people infected. ZMapp contains a cocktail of antibodies that attack proteins on the surface of the virus. These are the last known doses available; the company has said it will take months to build up even a modest supply.

Ebola was discovered in 1976 and, until this year, the world had recorded just 1,640 deaths from the deadly virus. On Wednesday, the World Health Organization reported that 128 new cases of the Ebola virus disease and 56 deaths were reported from Guinea, Liberia, Nigeria and Sierra Leone [2]. That brings the total this year to 1,069 people that have died of Ebola in West Africa. To put those numbers in perspective, almost 40% of all people known to have died from the Ebola virus have died in the current outbreak.

Although the outbreak is spreading at a frightening rate, it’s infecting people in a linear fashion; see the curves below for the number of suspected and confirmed Ebola cases (infection growth, not deaths) for each West African country. A linear spread means that each person is infecting on average around one other person.

A government laboratory in Canada has developed another Ebola vaccine and said earlier this week it will donate 800 to 1,000 doses to the World Health Organization. The CEO for NewLink Genetics, who licensed the vaccine from the Canadian government, has said the company could manufacture tens of thousands of doses over the next couple of months.

Yet two other drugs in development by Tekmira Pharmaceuticals and Sarepta Therapeutics, which use RNA interference to target the Ebola virus directly, could be tested in people affected. The development of Ebola drugs by both companies was stalled in August 2012 as federal agencies prepared for the sequestration at the beginning of 2013. Although Sarepta Therapeutics stopped developing their compound after the Defense Department halted its funding, the company has said it has enough experimental drug left over to treat about two dozen people.

Experts caution that most of these drugs are so early in development and in such limited quantities that they may not make a difference to those affected in West Africa.