30 June 2022 - - US-based pharmaceutical company Pfizer Inc. (NYSE: PFE) has submitted a New Drug Application to the US Food and Drug Administration for approval of Paxlovid (nirmatrelvir [PF-07321332] tablets and ritonavir tablets) for patients who are at high risk for progression to severe illness from COVID-19, the company said.

Paxlovid is currently authorized for emergency 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 kg [88 lbs]) with positive results of direct SARS-CoV-2 viral testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death.

The submission provides the longer-term follow-up data necessary for acceptance and potential approval.

According to the US Centers for Disease Control and Prevention, 50-60% of the US population is estimated to have one or more risk factors for progressing to severe COVID-19 illness.

These risk factors include any of the following: being aged 65 and older, obesity, diabetes, hypertension, smoking, physical inactivity, chronic kidney or liver disease, and immunocompromised conditions such as cancer, among others.

The NDA submission is supported by non-clinical and clinical data for Paxlovid.

It includes results from the Phase 2/3 EPIC-HR study (Evaluation of Protease Inhibition for COVID-19 in High-Risk Patients), which found that, compared to placebo, treatment with Paxlovid reduced the risk of hospitalization or death from any cause by 88% in non-hospitalized, high-risk adult patients treated within five days of symptom onset; results from the final Clinical Study Report showed an 86% reduction in relative risk.

The submission is also comprised of the most recent analyses from the Phase 2/3 EPIC-SR study (Evaluation of Protease Inhibition for COVID-19 in Standard-Risk Patients), which included data from both vaccinated patients with, and unvaccinated patients without, risk factors for severe COVID-19.

While the novel primary endpoint of self-reported, sustained alleviation of all symptoms for four consecutive days was not met, the data were supportive of the efficacy and safety data observed in EPIC-HR for use in patients at increased risk of progression to severe COVID-19 illness.

The NDA submission also includes an integrated analysis of data across the EPIC-HR and EPIC-SR studies, which showed an 84% reduction (p