Possible vaccine for Ebola went years untested on humans
GALVESTON, Texas — Almost a decade ago, scientists from Canada and the United States reported that they had created a vaccine that was 100 percent effective in protecting monkeys against the Ebola virus. The results were published in a respected journal, and health officials called them exciting. The researchers said tests in people might start within two years and a product could potentially be ready for licensing by 2010 or 2011.
It never happened. The vaccine sat on a shelf. Only now is it undergoing the most basic safety tests in humans — with nearly 5,000 people dead from Ebola and an epidemic raging out of control in West Africa.
Its development stalled in part because Ebola is rare and until now outbreaks had infected only a few hundred people at a time. But experts also acknowledge that the lack of follow-up on such a promising candidate reflects a broader failure to produce medicines and vaccines for diseases that afflict poor countries. Most drug companies have resisted spending the enormous sums needed to develop products useful mostly to countries with little ability to pay.
Now, as the growing epidemic devastates West Africa and is seen as a potential threat to other regions as well, governments and aid groups have begun to open their wallets.
A flurry of research to test drugs and vaccines is underway, with studies starting for several candidates, including the vaccine produced nearly a decade ago.
A federal official said in an interview Thursday that two large studies involving thousands of patients were planned to begin soon in West Africa and were expected to be described in detail Friday by the World Health Organization.
With no vaccines or proven drugs available, the stepped-up efforts are a desperate measure to stop a disease that has defied traditional means of containing it.
“There’s never been a big market for Ebola vaccines,” said Thomas W. Geisbert, an Ebola expert at the University of Texas Medical Branch in Galveston and one of the developers of the vaccine that worked so well in monkeys.
“So big pharma, who are they going to sell it to?” Geisbert added: “It takes a crisis sometimes to get people talking. ‘OK. We’ve got to do something here.’”
Dr. James E. Crowe Jr., director of a vaccine research center at Vanderbilt University, said that academic researchers who develop a prototype drug or vaccine that works in animals often encounter a “biotech valley of death” in which no drug company will help them cross the finish line.
The Ebola vaccine on which Geisbert collaborated is made from another virus, vesicular stomatitis virus, which causes a mouth disease in cattle but rarely infects people. It had already been used successfully in making other vaccines.
The researchers altered VSV by removing one of its genes, rendering the virus harmless, and inserting a gene from Ebola. The transplanted gene forces VSV to sprout Ebola proteins on its surface. The proteins cannot cause illness, but they provoke an immune response that in monkeys, considered a good surrogate for humans, fought off the disease.
The vaccine was actually produced, in Winnipeg by the Public Health Agency of Canada. The Canadian government patented it, and 800 to 1,000 vials of the vaccine were produced. In 2010, it licensed the vaccine, known as VSV-EBOV, to NewLink Genetics, in Ames, Iowa.
The Canadian government donated the existing vials to the World Health Organization, and safety tests of the vaccine in healthy volunteers have already begun.
NewLink’s product is one of two leading vaccines being tested. The other, which uses a cold virus that infects chimpanzees, was developed by researchers at the National Institutes of Health and Glaxo-SmithKline. The first tests of an earlier version of it, employing a different cold virus, began in 2003.
Several other vaccine candidates, not as far along, are also in the pipeline and may be ready for safety testing next year. Once any drugs or treatments pass the safety tests they will be available for use in larger numbers of people, and health officials are grappling with whether they should be tested for efficacy in the traditional way, in which some people at risk are given placebos instead of the active drug.
Governments and the military became interested in making vaccines against Ebola and a related virus, Marburg, during the 1990s after a Soviet defector said the Russians had found a way to weaponize Marburg and load it into warheads. Concerns intensified in 2001 after the Sept. 11 terrorist attacks and anthrax mailings.
The government money led to major advances in the laboratory, Geisbert said, but was insufficient to cover the huge costs of human trials.
Nor could the small companies that were involved in the early studies in animals afford to pay for human trials. No finished product came to market.
Geisbert moved on, working on treatments for Ebola and another version of the VSV vaccine. For the vaccine work, his main collaborator has been Dr. Heinz Feldmann, chief of virology at the Rocky Mountain Laboratories in Hamilton, Mont., part of the National Institute of Allergy and Infectious Diseases.