Although ZMapp was once praised as a wonder drug against the deadly Ebola virus, but it recently fell short of the bar for effectiveness in a clinical trial, researchers revealed.
According to an AFP release as published in the Guardian, experts pointed out that ZMapp helped more people survive, compared to those who received the standard therapy of intravenous fluids and medical care.
“It is likely that this drug had a significant effect. It is not a miraculous effect,” said Jesse Goodman, a doctor and infectious disease expert at Georgetown University who was not involved in the study.
A total of 37 percent of patients died after receiving standard treatment alone, compared to 22 percent who died after receiving standard therapy plus ZMapp, made by Mapp Pharmaceuticals in San Diego, California, according to the study in the New England Journal of Medicine.
Those who were given ZMapp saw a 40 percent lower relative risk of dying than those who did not get it.
Statistically, this meant 91 percent likelihood that ZMapp was better than the current standard of care alone.
Before the trial began, researchers established that the drug would have to meet a 97.5 percent probability threshold to be declared superior to hydration and hospital care.
A key setback for the phase II clinical trial undertaken in Sierra Leone, Guinea, Liberia and the United States was that the deadly epidemic was winding down by the time the research got under way.
Only 72 people enrolled instead of the hoped-for 200 patients during the study which ran from March 2015 to January 2016.
The Ebola outbreak swept across West Africa from late 2013 to until 2016, and killed more than 11,000 people.
Ebola is spread by contact with bodily fluids, and causes a range of symptoms, from fever and body aches to vomiting, diarrhea and hemorrhage.
According to the World Health Organization, Ebola has killed up to 90 percent of those infected during some outbreaks, though the average chance of survival is about 50-50.
There is no drug on the market to treat Ebola.
As an experimental therapy not yet approved by regulators, ZMapp was granted fast-track status by the US Food and Drug Administration last year, a designation aimed at speeding its arrival on the market.
At the height of the Ebola epidemic, ZMapp rose to fame as the possible reason why some patients had reached the brink of death and survived.
It was touted as key reason why American missionary Kent Brantly was able to pull through, after becoming infected while treating Ebola patients in Liberia.
Grown in tobacco leaves, ZMapp was also scarce, with a limited amount of doses ever made.It even stoked controversy when some claimed that white missionaries were more likely to receive it than African patients and medical workers who fell ill.
But a top doctor in Sierra Leone, Martin Salia, who also became sick with Ebola while treating patients, was given ZMapp and died anyway. Doctors later said it appeared his disease had been too advanced by the time he was treated.