US biopharmaceutical company Gilead Sciences Inc's (Nasdaq:GILD) antiviral drug remdesivir, for treating patients hospitalised with COVID-19, has gained approval of the US Food and Drug Administration (FDA) on 22 October 2020, making it the first and only drug approved for the disease in the US, Reuters news agency reported on Friday.

Remdesivir has been available under an FDA emergency use authorisation (EUA) since May 2020, after a study led by the National Institutes of Health showed it reduced hospital stays by five days.

This comes as the World Health Organisation (WHO) said its global trial of COVID-19 therapies found that remdesivir did not have a substantial effect on patients' length of hospital stay or chances of survival. That study has not been reviewed by outside experts.

Reportedly, Gilead has questioned the potential for bias in the WHO study, which was not "blinded," meaning that patients and their doctors were aware of which treatments were being used.

Remdesivir, which will be sold under the brand name Veklury, costs USD3,120 for a five-day treatment course, or USD2,340 for government purchasers such as the Department of Veterans Affairs.

According to Gilead, it is currently meeting demand for the drug in the US and anticipates meeting global demand by the end of October 2020. Veklury has regulatory approvals or temporary authorisations in about 50 additional countries.

Also on Friday the US FDA issued a new emergency use authorisation for remdesivir to treat hospitalised paediatric patients under age 12 who weigh enough to receive an intravenous drug.