TORONTO -- Early testing of an antiviral medication originally intended for Ebola treatment is showing hopeful signs in the fight against COVID-19, but experts believe more research is needed before it can be widely used.

Remdesivir has not been approved for use anywhere in the world, but is among the leading contenders for future COVID-19 treatments and studies suggest positive -- albeit early -- results.

In a study published in The New England Journal of Medicine and funded by the makers remdesivir, Gilead Sciences, 61 critically ill COVID-19 patients were given a 10-day course of the drug under “compassionate use” provisions, which allows patients with severe illnesses to take medications that are not yet approved for wider use.

Of the 53 patients whose data proved usable, 68 per cent had improved and 53 per cent had been taking off their ventilators. Thirteen per cent of the patients died, however.

Among the 53 patients in the study, 22 were American, 22 were from Canada or Europe and another nine were from Japan.

Dr. Danny Chen at Mackenzie Health outside Toronto treated one of his COVID-19 patients with remdesivir and has since noticed an improvement. 

“She's definitely improved clinically,” he told CTV News. “She's now able to sit up by herself. She is breathing on her own without the assistance of a machine.

While she is still in the intensive care unit, it’s likely she’ll be discharged from the intensive care into the regular ward probably within the next couple of days.”

Remdesivir also showed positive results in recent animal testing, where it helped prevent infection and reduced the symptoms of SARS and MERS, viruses similarly related to COVID-19.

While the results appear promising, Chen still believes further research is needed as this study did not have a control to compare the results to.

“The problem is that currently we don't know what truly works, so if everyone just prescribes whatever they think is going to work, then we will never know what truly is an effective therapy for this virus,” he said.

In an open letter last week, Gilead Sciences Chairman and CEO Daniel O’Day acknowledged some of the issues experts have with the study, but added it results are significant for those who took the drug and are now recovering.

“We recognize the limitations of these compassionate use data from a purely investigational perspective, while knowing they are of the greatest significance for the patients whose symptoms improved,” he wrote in the letter.

The results are promising for ­Matthias Gotte, a virologist at the University of Alberta, who produced a study back in February concerning how remdesivir works against coronaviruses. He believes Remdesivir is the leading contender in the race for COVID-19 treatment.

“It is absolutely critical because we do not have any approved drug at the moment for the treatment of infection with any coronavirus,” he said back in March. 

More information on the drug’s effectiveness could soon be available as well.

Gilead supplied remdesivir for two studies in China, where results are expected by the end of the month. There are other studies being done in the U.S.: one where treatment is being compared over time, and another using moderately sick patients compared to traditional care.

With files from The Associated Press