Pfizer starts testing its oral COVID-19 antiviral drugs in adult patients

FILE PHOTO: A vial labelled with the Pfizer-BioNTech coronavirus disease (COVID-19) vaccine is seen in this illustration picture taken March 19, 2021. REUTERS/Dado Ruvic/Illustration/File Photo

Pfizer Inc said on Wednesday it had started dosing in a mid-to-late-stage trial of its oral antiviral therapy for COVID-19 in non-hospitalized, symptomatic adult patients.

The company and its rivals, including U.S.-based Merck & Co Inc and Swiss pharmaceutical Roche Holding AG, have been racing to develop the first antiviral pill to be taken on early signs of the illness.

Pfizer’s mid-to-late-stage trial in 1,140 participants would study the therapy, PF-07321332, in combination with a low dose of ritonavir, which has been used with other antivirals too, the company said.

PF-07321332 is designed to block the activity of a key enzyme that is needed for the coronavirus to replicate.

To date, Gilead Sciences Inc’s remdesivir, administered intravenously, is the only approved antiviral treatment for COVID-19 in the United States.

Merck and partner Ridgeback Biotherapeutics’ molnupiravir is already being studied in a late-stage trial in non-hospitalized patients to see if it reduces the risk of hospitalization or death.

The companies said on Wednesday they had started a late-stage trial of molnupiravir for the prevention of COVID-19 infection.

Pfizer said in July if the PF-07321332 trial was successful, it would file for a potential emergency use authorization in the fourth quarter.