PF-07321332 is an orally active covalent inhibitor of the 3C-like protease by direct binding of the catalytic cysteine 145. 3CL protease cleaves polyproteins 1a and 1ab of SARS-CoV-2, a step required for reproduce the virus. The PF-07321332/ritonavir combination drug (trade name Paxlovid) is efficient for the treatment of COVID-19 as, in November 2021, Pfizer announced phase 2/3 clinal trial results that the drug treatment reduced 89% in hospitalizations when given within three days after symptom onset. This product is for research use only.
