The US Food and Drug Administration (FDA) has granted full approval to Pfizer’s oral antiviral Paxlovid for the treatment of mild-to-moderate COVID-19 in adults who are at high risk for progression to severe COVID-19, including hospitalization or death.
Paxlovid (nirmatrelvir tablets and ritonavir tablets, co-packaged for oral use) is the fourth drug—and first oral antiviral pill—approved by the FDA to treat COVID-19 in adults, according to a release from the FDA.
Paxlovid manufactured and packaged under the emergency use authorization and distributed by the US Department of Health and Human Services will continue to be available to ensure continued access for adults, as well as treatment of eligible children ages 12 to 18 who are not covered by this approval. Paxlovid is not approved or authorized for use as a pre-exposure or post-exposure prophylaxis for the prevention of COVID-19.
“While the pandemic has been challenging for all of us, we have made great progress mitigating the impact of COVID-19 on our lives,” says Patrizia Cavazzoni, MD, director for the FDA’s Center for Drug Evaluation and Research, in a release. “Today’s approval demonstrates that Paxlovid has met the agency’s rigorous standards for safety and effectiveness and that it remains an important treatment option for people at high risk for progression to severe COVID-19, including those with prior immunity. The FDA remains committed to working with sponsors to facilitate the development of new prevention and treatment options for COVID-19.”
The efficacy of Paxlovid was primarily supported by the final results of the EPIC-HR clinical trial. EPIC-HR was a randomized, double-blind, placebo-controlled clinical trial studying Paxlovid for the treatment of non-hospitalized symptomatic adults with a laboratory-confirmed diagnosis of SARS-CoV-2 infection.
Patients were adults 18 years of age and older with a prespecified risk factor for progression to severe disease or were 60 years and older regardless of prespecified chronic medical conditions. All patients had not received a COVID-19 vaccine and had not been previously infected with COVID-19.
Paxlovid significantly reduced the proportion of people with COVID-19 related hospitalization or death from any cause through 28 days of follow-up by 86% compared to placebo among patients treated within five days of symptom onset and who did not receive COVID-19 therapeutic monoclonal antibody treatment. In this analysis, 977 patients received Paxlovid, and 989 patients received placebo, and among these patients, 0.9% who received Paxlovid were hospitalized due to COVID-19 or died from any cause during 28 days of follow-up compared to 6.5% of the patients who received the placebo.
Benefit of Paxlovid was observed in patients with prior immunity to the virus that causes COVID-19. Among patients in EPIC-HR who were antibody positive at trial enrollment, the risk of COVID-19-related hospitalization or death from any cause during 28 days of follow-up was 0.2% among the 490 patients treated with Paxlovid compared with 1.7% of the 479 patients receiving placebo.
EPIC-SR was another clinical trial that enrolled vaccinated patients with at least one risk factor for progression to severe COVID-19. Although not statistically significant, among these vaccinated patients, there was a reduction in the risk of COVID-19-related hospitalization or death from any cause.
EPIC-HR and EPIC-SR were randomized controlled trials and provide information about COVID-19 rebound. Data from these two trials showed that rebound in SARS-CoV-2 (RNA or virus) shedding or COVID-19 symptoms occurred in a subset of patients and happened in both the patients receiving Paxlovid and the placebo. Based on the data currently available to the FDA, there is not a clear association between Paxlovid treatment and COVID-19 rebound.
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