Canadian researchers said on Wednesday they have developed an antibody treatment that may be able to prevent death from Ebola virus even when given three full days after infection.
The findings, published in the U.S. journal Science Translational Medicine, suggested that it may be possible to develop a cure for Ebola even after the virus can be detected in the blood and disease symptoms have become apparent.
Although rare, Ebola virus is considered one of the most if not the most aggressive virus known to date in part because of its rapidity to kill, which can be within one week from exposure or three to four days from when the first symptoms become apparent. This leaves very little time for any treatment to act and save a sick individual.
“For this reason, such a treatment has been considered by many to be closer to the domain of science fiction than contemporary scientific research,” lead author Qiu Xiangguo at the Public Health Agency of Canada told Xinhua.
In their study, the researchers gave Ebola-infected monkeys a treatment made of three specific antibodies in combination with interferon alpha, a molecule that is produced naturally by the body to fight viruses.
The antibodies are “like three little but powerful missiles” that target three different outer regions of the virus, Qiu said. Once in contact with the virus external coat, these antibodies interfere with the virus lifecycle and reduce the ability of the virus to reproduce. At the same time, the interferon alpha boosts the defenses of the infected individual by stimulating a natural but rapid and robust anti-viral response, she said.
The combination of antibody and interferon therapy was 75 percent and 100 percent protective in cynomolgus and rhesus monkeys when given three days post-infection. About half of the cynomolgus monkeys were protected at four days post-infection in cases where only interferon alpha was given earlier, one day post- infection, Qiu said.
“Although we were very optimistic we were not expecting to see 100 percent survival in Ebola-infected non-human primates when treated only three days before they succumb to the disease on average,” Qiu said.
“This study shows that what seemed impossible to many, i.e. to develop a cure capable of stopping Ebola virus on its track only a few days before death, has now been made and proven efficacious in conditions that are at least as serious if not more severe than what has been observed and described in humans,” she added.
The researchers said they have tentatively scheduled a phase I safety trial, slated for the end of 2014 or early 2015, to test the combination therapy in humans. PNA