What if the cure for Ebola were already in your local pharmacy?
That's the question that Gene Olinger and his colleagues are trying to answer in a project funded by the Defense Threat Reduction Agency and National Institutes of Health. Working off a list of Food and Drug Administration-approved, "off the shelf" drugs and adding in other common small molecules such as metals, herbs and food additives, the researchers came up with 2,700 promising compounds. They tested each in cell cultures and found that 171 appeared to have some antiviral activity against Ebola.
They prioritized the 30 best for additional testing in mice. They infected the animals with Ebola and found that a number of drugs seemed to have a positive effect and that two of them actually stopped the mice from getting sick at all.
Seventy percent of the group given the antidepressant Zoloft survived, and 100 percent of the group given the calcium channel blocker Vascor — typically used in heart patients to lower blood pressure — survived. In contrast, all the mice in both control groups, which received no treatment, died within 10 days.
"It was quite shocking that some of these drugs worked. To be honest, we didn't think some of these would," Olinger, a scientist under contract with the National Institute of Allergy and Infectious Diseases, said in an interview.
Using an approved drug to treat a novel disease has many advantages for both practical and scientific reasons. It's easier to create stockpiles of pills or injections if factories are set up to the right standards and there would be less paperwork and other time-consuming bureaucracy to get through. Moreover, there would be less worry about toxic side effects since drugs on the market have already been proved safe for use in humans.
Olinger cautioned that there is still a long way to go before we know whether any of the information from the study can be translated into a treatment for humans. A lot of drugs that look miraculous in mice end up doing nothing in humans. The researchers' next step is to test a handful of the drugs in guinea pigs and primates and to try to figure out what mechanisms may have led to blocking the progression of the virus.
He said he believes it's possible there may be a combination of drugs that could work as a treatment, but that there's a much lower bar to developing a prophylactic for someone upon immediate exposure or suspicion of exposure rather than one for a patient with full-blown symptoms.
The group is posting its data sets online to try to crowdsource some of these answers.
"Today’s science world is data rich. We may have missed something in the data and either tomorrow or many years for now another researcher may interpret differently and find a different answer," Olinger said.
The World Health Organization, NIH and Department of Defense will collectively decide how to move forward with human testing if and when the research advances to that stage. Scientists are also working on trying to figure out whether the blood plasma treatment given to a handful of patients can be made more widely available and working on testing several Ebola vaccine candidates.