A biotech company says its experimental drug has proved effective against the new coronavirus in a major U.S. government study that put it to a strict test.

Gilead Sciences’s remdesivir would be the first treatment to pass such a test against the virus, which has killed more than 218,000 people since it emerged late last year.

Having a treatment could have a profound effect on the global pandemic, especially because health officials say any vaccine is likely a year or more away.

The study, run by the National Institutes of Health, tested remdesivir versus usual care in about 800 hospitalized coronavirus patients around the world. The main result is how long it takes patients to recover.

Gilead gave no details on results Wednesday, but said an announcement is expected soon. NIH officials did not immediately reply to a request for comment.

Remdesivir is given through an IV and is designed to interfere with an enzyme that reproduces viral genetic material. In animal tests against SARS and MERS, diseases caused by similar coronaviruses, the drug helped prevent infection and reduced the severity of symptoms when given early enough in the course of illness.

But it is not yet approved anywhere in the world for any use.