Description: Nirmatrelvir (PF-07321332), the key component of Paxlovid [Nirmatrelvir (PF-07321332) and ritonavir] which is newly approved COVID-19 oral antiviral drug, is an orally bioavailable 3C-like protease (3CLPRO) inhibitor with potent antiviral effects against SARS-CoV-2 virus and COVID-19. On December 22, 2021, FDA issued an emergency use authorization (EUA) for Pfizer's Paxlovid (nirmatrelvir tablets and ritonavir tablets, co-packaged for oral use) for the treatment of mild-to-moderate COVID-19 in adults and pediatric patients (12 years of age and older weighing at least 40 kilograms or about 88 pounds) with positive results of direct SARS-CoV-2 testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death. On Nove 6th 2021, Pfizer announced that Paxlovid significantly reduced hospitalization and death, based on an interim analysis of the Phase 2/3 EPIC-HR (Evaluation of Protease Inhibition for COVID-19 in High-Risk Patients) randomized, double-blind study of non-hospitalized adult patients with COVID-19, who are at high risk of progressing to severe illness.

References: KoenVandyck, et al. Considerations for the Discovery and Development of 3-Chymotrypsin-Like Cysteine Protease Inhibitors Targeting SARS-CoV-2 Infection. Current Opinion in Virology Available online 27 April 2021