FDA Issues EUA for COVID-19 Oral Antiviral Treatment From Pfizer for At-Home Use

The FDA has issued an emergency use authorization (EUA) for nirmatrelvir (PF-07321332) tablets and ritonavir tablets (Paxlovid, Pfizer) for the treatment of mild-to-moderate COVID-19 in adults and pediatric patients aged 12 years and older, following positive SARS-CoV-2 viral test results.

Specifically, the EUA is for patients who weigh at least 88 lbs and who are at high risk for progression to severe COVID-19, including hospitalization or death.

The oral antiviral treatment includes nirmatrelvir, a novel main protease (Mpro) inhibitor that was specifically designed to block SARS-CoV-2 Mpro activity. Mpro is an enzyme that the coronavirus must replicate to advance and progress within the body.

“Today’s authorization of Paxlovid represents another tremendous example of how science will help us ultimately defeat this pandemic, which, even 2 years in continues to disrupt and devastate lives across the world,” Albert Bourla, chairman and CEO of Pfizer, said in a statement.

The FDA’s decision to issue an EUA for this oral antiviral treatment was based on clinical data from the phase 2/3 EPIC-HR trial. During this trial, investigators enrolled non-hospitalized patients aged 18 years and older who had positive COVID-19 test results and who were at increased risk of progressing to severe illness. The trial data showed patients experienced an 89% reduction in risk of COVID-19-related hospitalization or death when treated with the oral antiviral within 3 days of symptom onset compared with patients on the placebo.

The investigators noted that, in the treatment group, no patient deaths occurred. However, in the placebo group, 9 deaths had occurred by day 28. Investigators also observed similar results in those treated within 5 days of symptom onset, as these patients experienced an 88% reduction in risk with no deaths occurring.

During the trial, investigators found the treatment-emergent adverse events (AEs) from the oral antiviral were comparable to the placebo (23% vs 24%). Furthermore, most of the AEs were found to be mild in intensity.

Although the clinical trials assessing the oral antiviral did not include patients under aged 18 years, the trial investigators noted an expectation that the authorized adult dosing regimen would be comparable in pediatric patients aged 12 years and older weighing at least 40 kg.

Additionally, further phase 2/3 clinical trials are ongoing in adults at standard risk of progressing to severe illness from COVID-19 (ie, low risk of hospitalization or death) and in patients who have been exposed to the virus through exposure within their households.

With the oral antiviral for COVID-19 receiving this EUA from the FDA, Pfizer noted in the statement that the company is ready to begin delivery of the treatment to the United States immediately. In November 2021, an agreement between Pfizer and the US government had been settled that established a supply of 10 million treatment courses of the oral antiviral treatment to be delivered to the United States, with the completion of the delivery fulfillment expected in 2022.

“This breakthrough therapy, which has been shown to significantly reduce hospitalizations and deaths and can be taken at home, will change the way we treat COVID-19, and hopefully help reduce some of the significant pressures facing our health care and hospital systems,” Bourla said. “Pfizer stands ready to begin delivery in the United States immediately to help get Paxlovid into the hands of appropriate patients as quickly as possible.”

Reference

Pfizer receives U.S. FDA emergency use authorization for novel COVID-19 oral antiviral treatment. Pfizer. News release. December 22, 2021. Accessed December 22, 2021. https://www.businesswire.com/news/home/20211221005795/en/Pfizer-Receives-U.S.-FDA-Emergency-Use-Authorization-for-Novel-COVID-19-Oral-Antiviral-Treatment