Ebola: Are Treatments, Vaccines on the Horizon?
Other New Hopes continued...
On the treatment side, an early-stage safety trial of an anti-Ebola therapy developed by Tekmira Pharmaceuticals began in January in healthy volunteers. The Vancouver company announced in early July the FDA had put the trial on hold until safety concerns are resolved. The therapy, called TKM-Ebola, is under FDA “fast-track” status. It's been shown to be 100% effective in treating Ebola-infected monkeys.
On Aug. 7, though, Tekmira said the FDA had changed the full hold placed on TKM-Ebola to a “partial clinical hold. This action enables the potential use of TKM-Ebola in individuals infected with Ebola virus,” the company said in a statement.
“We are pleased that the FDA has considered the risk-reward of TKM-Ebola for infected patients,” said Tekmira president and CEO Mark Murray, PhD, in the statement. “We have been closely watching the Ebola virus outbreak and its consequences, and we are willing to assist with any responsible use of TKM-Ebola. The foresight shown by the FDA removes one potential roadblock to doing so.”
Another treatment that's been tried but not formally studied in people is using the blood of an infected person. Samaritan’s Purse has said Brantly received a unit of blood from a 14-year-old boy, a former patient of his who recovered from Ebola.
The boy’s blood would have antibodies against the lethal virus, so giving it to someone battling the disease “makes all the sense in the world,” Eldridge says. “There’s clear evidence that antibodies will protect against Ebola infection.” Because Brantly also received the experimental serum, it will be hard to know which treatment helped or if his health would have improved on its own.
Another path to an Ebola vaccine would be to do studies in animals under the FDA’s Animal Rule, a “very long process,” says M. Javad Aman, PhD. He's a former research scientist at the U.S. Army Medical Research Institute of Infectious Diseases.
The rule applies to drugs and biological products, such as vaccines, developed to treat or prevent serious or life-threatening conditions caused by exposure to toxic substances. Because it would be unethical to test such drugs or biological products by deliberately exposing people to a toxic substance, the Animal Rule allows the FDA to approve them based on how well they work in animals. The agency applied the Animal Rule in December 2012 to approve raxibacumab injection for treatment and prevention of inhaled anthrax.
Aman is the co-founder of Integrated BioTherapeutics, or IBT, in Gaithersburg, MD. IBT has developed an Ebola vaccine that, like the vaccines against HPV (human papillomavirus), uses “virus-like particles,” or VLPs. VLPs are like a sheep in wolf’s clothing. They contain proteins found on the surface of a virus, evoking an immune response, but they lack viral genetic material, so they can’t make people sick. The IBT vaccine is intended to protect wild gorillas and chimpanzees, for which Ebola is now considered as big a threat as poaching and habitat loss, according to the company.