The experimental drug Remdesivir is being described by the America’s top infectious disease expert as the first effective treatment for the coronavirus.

Dr Anthony Fauci said antiviral – which was developed for Ebola – has been proven to “block the virus”.

The US health chief went so far as to liken it to the discovery of the first medicine found to help treat HIV more than three decades ago.

More cautiously, Gilead Sciences, the pharmaceutical company that created the drug, stated the results from phase three of an experimental trial have not yet demonstrated the drug to be “safe or effective” in treating COVID-19 – but had promising early results.

Spearheading the drug trial is the National Institute for Allergy and Infectious Diseases whose director Dr Fauci said Remdesivir had a “clear-cut, significant, positive effect in diminishing the time to recovery”.

Gilead Sciences said it was “aware of positive data emerging” from the government’s drug trial which evaluated five-day and 10-day dosing durations of Remdesivir in patients with severe manifestations of the coronavirus.

“We understand that the trial has met its primary endpoint and that NIAID will provide detailed information at an upcoming briefing,” it said in a press release on Thursday morning (Australian time).

The trial found those who were given Remdesivir over a 10-day period showed similar signs of improvement to those taking a five-day treatment course.

Gilead Sciences chief medical officer Merdad Parsey said the study demonstrated “the potential for some patients to be treated with a five-day regimen, which could significantly expand the number of patients who could be treated with our current supply of Remdesivir”

“This is particularly important in the setting of a pandemic, to help hospitals and healthcare workers treat more patients in urgent need of care,” Dr Parsey said in a statement.

The World Health Organisation said it was too early to comment on the trial’s results, as it could not go simply off the statement put out by Gilead Sciences without any evidence.

Gilead Sciences said it plans to submit the full data for publication in a peer-reviewed journal in the coming weeks.

Remdesivir was originally developed to treat Ebola.

The lead investigator of the study Aruna Subramanian, from Stanford University said the results were encouraging.

“While additional data are still needed, these results help to bring a clearer understanding of how treatment with Remdesivir may be optimized, if proven safe and effective,” she said.