Pfizer unveils its oral SARS-CoV-2 inhibitor
Bethany Halford
Abstract
Drugmaker Pfizer presented its oral COVID-19 antiviral clinical candidate PF-07321332 last week at ACS Spring 2021. The compound, which is currently in Phase 1 clinical trials, is the first orally administered compound in the clinic that targets the main protease (also called Mpro or the 3CL protease) of SARS-CoV-2, the virus that causes COVID-19. By inhibiting the main protease, PF-07321332 prevents the virus from cleaving long protein chains into the parts it needs to reproduce itself. Dafydd Owen, director of medicinal chemistry at Pfizer, revealed the compound’s structure. Last year, Pfizer reported PF-07304814 , a different small-molecule inhibitor of SARS-CoV-2’s main protease. The work to develop that compound began during the 2002–3 outbreak of severe acute respiratory syndrome. But that molecule can be administered only intravenously, which limits its use to hospitals. Because PF-07321332 can be taken orally, as a pill or capsule, it could be given outside hospitals if