Pfizer begins study of oral drug for prevention of Covid-19
![A vial of the Pfizer vaccine against the coronavirus disease (Covid-19) is seen as medical staff are vaccinated at Sheba Medical Center in Ramat Gan, Israel December 19, 2020. REUTERS/Amir Cohen/File Photo](https://947631.windlasstrade-hk.tech/sites/default/files/styles/big_2/public/images/2021/07/06/pwuhc7kpinnm5j23emnzblfex4.jpg)
Pfizer Inc said on Monday it has started a mid-to-late-stage study testing its investigational oral antiviral drug for the prevention of Covid-19 infection among those who have been exposed to the virus.
The company and its rivals, including US-based Merck & Co Inc and Swiss pharmaceutical Roche Holding AG, have been racing to develop the first antiviral pill for Covid-19.
Pfizer said it would study the drug, PF-07321332, in up to 2,660 healthy adult participants aged 18 and older who live in the same household as an individual with a confirmed symptomatic Covid-19 infection.
The trial would test PF-07321332 with a low dose of ritonavir, an older medication widely used in combination treatments for HIV infection.
Merck and partner Ridgeback Biotherapeutics said earlier this month they had begun enrolling patients in a late-stage trial of their experimental drug molnupiravir for prevention of Covid-19 infection.
Pfizer had also said earlier this month it started a mid-to-late-stage trial of PF-07321332 for the treatment of Covid-19 in non-hospitalized, symptomatic adult patients.