Pfizer is seeking emergency use authorization (EUA) for its investigational COVID-19 oral antiviral PF-07321332/ritonavir (Paxlovid) for the treatment of mild to moderate COVID-19 in patients at increased risk of hospitalization or death. The drug is a SARS-CoV-2 protease inhibitor that inhibits the viral replication of SARS-CoV-2 by blocking the activity of the SARS-CoV-2-3CL protease. If approved, it would be used during COVID-19 illness.
The oral antiviral was shown in a phase 2/3 clinical trial comparing safety and efficacy of Paxlovid to placebo in 1,219 patients with laboratory-confirmed SARS-CoV-2 infection within a 5-day period with mild to moderate symptoms. Patients had at least one characteristic or underlying condition associated with increased risk of developing severe illness from COVID-19.
Interim analysis of data showed that patients receiving Paxlovid treatment had a significantly greater reduction in the risk of COVID-19-related hospitalization or death from any cause within 3 days of symptoms onset compared with placebo. Similar findings were reported in patients treated within 5 days of symptom onset. There were no deaths reported in the Paxlovid arm of the study versus 10 deaths in the placebo arm.
