Gilead Sciences Inc's drug, remdesivir, showed antiviral activity against omicron, delta and other variants of the coronavirus in laboratory studies, the company said on Friday.

The study results showed similar activity of remdesivir against the variants and an early ancestral strain of the virus detected in Seattle, Washington, Gilead said.

Remdesivir, marketed as Veklury, was approved by the FDA in October 2020 to treat hospitalized COVID-19 patients. Last month, this was expanded to non-hospitalized patients who were at high risk of severe disease.

Gilead added that the viral enzyme of the coronavirus that remdesivir targets does not contain any additional unique mutations.

"Now with a new version of omicron (BA.2 subvariant) increasing in circulation around the world, these latest data also suggest that remdesivir will retain antiviral activity against this new subvariant," said Tomas Cihlar, senior vice president of virology research at Gilead.