The U.S. Food and Drug Administration (FDA) granted emergency use of the experimental antiviral drug remdesivir to treat COVID-19 on Friday, a move the U.S. President Donald Trump announced over a meeting at the White House with the drug's manufacturer Gilead Science company.

"It's the first authorized therapy for COVID-19, so we're really proud to be part of it," FDA Commissioner Stephen Hahn said during the meeting.

The authorization will be applied to severely ill COVID-19 patients, and those with respiratory problems who need supplemental oxygen or ventilators.

Preliminary results of remdesivir's clinical trials show the drug can shorten the time to recovery by 31 percent for hospitalized patients, compared to a placebo treatment, according to the data released by U.S. National Institute of Health.

It suggests the drug may also help avert deaths, but that effect is not yet large enough for scientists to know for sure.

The company said at the meeting they will donate 1.5 million vials of the drug to help patients, and will work with the government to figure out best ways to distribute those drugs.

It is expected to be enough for at least 140,000 patients, depending on the number of days they need to be treated.

Different fate of remdesivir in China

Dubbed as one of the world's most hopeful drug for treating the novel coronavirus disease, remdesivir's clinical trials are showing varying results in China and the United States. 

Another study based on a similar trial design enrolled 237 COVID-19 patients from 10 hospitals in Wuhan.

It found that "remdesivir does not speed up recovery from COVID-19 compared with placebo in hospitalized patients who are critically ill."

"Unfortunately, our trial found that while safe and adequately tolerated, remdesivir did not provide significant benefits over placebo," said professor Cao Bin from China-Japan Friendship Hospital and Capital Medical University in China, who led the research.

The experiment had been terminated by the company and Chinese scientists in early April.

Both of the clinical results have been published in the peer-reviewed journal. University of Edinburgh professor John Norrie, who was not involved with the study, said, "the particular challenges of delivering pandemic trials underline the importance of data sharing, allowing rapid curation of relevant datasets for individual patient data meta-analyses.

According to Reuters, remdesivir was previously available only for patients enrolled in clinical trials or for patients cleared to get the drug under expanded use and compassionate use programs. 

Through their program, more than 181 hospital locations around the world, including hospitals in 27 U.S. states, have been administering the drug.