Nirmatrelvir

Nirmatrelvir (PF-07321332) is an orally bioavailable 3C-like protease (3CL) inhibitor that is the subject of clinical trial NCT04756531. 3CL is responsible for cleaving polyproteins 1a and 1ab of SARS-CoV-2. Without the activity of the SARS-CoV-2 3CL, nonstructural proteins (including proteases) cannot be released to perform their functions, inhibiting viral replication. In 2020, Pfizer was investigating another potential treatment for SARS-CoV-2, PF-07304814. Both drugs were inhibitors of SARS-CoV-2 3CL, but nirmatrelvir has the advantage of being orally bioavailable. Nirmatrelvir is advantageous in that it can be prescribed to patients before they require hospitalization, while PF-07304814 requires intravenous administration in hospital. In December 2021, the FDA granted an emergency use authorization to Paxlovid, a co-packaged product containing both nirmatrelvir and ritonavir, for the treatment of certain patients with mild-to-moderate COVID-19. It was fully approved by the FDA on May 25, 2023. Paxlovid was approved for use in Canada in January 2022 for the treatment of adult patients with mild-moderate COVID-19 and later granted conditional marketing authorization by the European Commission on January 27, 2022.

Nirmatrelvir (PF-07321332) is an orally bioavailable 3C-like protease (3CL) inhibitor that is the subject of clinical trial NCT04756531. 3CL is responsible for cleaving polyproteins 1a and 1ab of SARS-CoV-2. Without the activity of the SARS-CoV-2 3CL, nonstructural proteins (including proteases) cannot be released to perform their functions, inhibiting viral replication. In 2020, Pfizer was investigating another potential treatment for SARS-CoV-2, PF-07304814. Both drugs were inhibitors of SARS-CoV-2 3CL, but nirmatrelvir has the advantage of being orally bioavailable. Nirmatrelvir is advantageous in that it can be prescribed to patients before they require hospitalization, while PF-07304814 requires intravenous administration in hospital. In December 2021, the FDA granted an emergency use authorization to Paxlovid, a co-packaged product containing both nirmatrelvir and ritonavir, for the treatment of certain patients with mild-to-moderate COVID-19. It was fully approved by the FDA on May 25, 2023. Paxlovid was approved for use in Canada in January 2022 for the treatment of adult patients with mild-moderate COVID-19 and later granted conditional marketing authorization by the European Commission on January 27, 2022.

In the US, Europe, and Canada, nirmatrelvir, in combination with ritonavir, is indicated for the treatment of mild-to-moderate coronavirus disease 2019 (COVID-19) in adults who are at high risk for progression to severe COVID-19, including hospitalization or death. In Europe, this therapeutic indication is approved under conditional marketing authorization.

• Mild, moderate Novel Coronavirus Infectious Disease (COVID-19)