Pfizer Seeks Full FDA Approval for Oral COVID-19 Therapy Paxlovid

Pfizer is jockeying for full FDA approval of its oral antiviral COVID-19 treatment, Paxlovid, which would allow the company to sell the drug commercially.

Pfizer announced Thursday that it’s seeking the green light for Paxlovid (nirmatrelvir tablets and ritonavir tablets) in the U.S. for both vaccinated and unvaccinated individuals at high risk for progression to severe illness from COVID-19, which is consistent with its current Emergency Use Authorization (EUA).

Final results of one of Pfizer’s studies on Paxlovid showed an 86 percent reduction in relative risk of hospitalizations or death from any cause, the company said. No deaths occurred in patients treated with Paxlovid through week 24 of the study, compared to 15 deaths observed with placebo.

The submission to the FDA also included the most recent analyses from a second phase 2/3 study that didn’t meet the novel primary endpoint of self-reported, sustained alleviation of all symptoms for four consecutive days. However, the data were supportive of the efficacy and safety data observed in Pfizer’s other study of Paxlovid in patients at increased risk of progression to severe COVID-19 illness, the company said.

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

“Data from our clinical development program, coupled with the more than 1.7 million patients around the world who have been prescribed our oral treatment to date, reinforce Paxlovid as an important treatment option for mild-to-moderate COVID-19 in patients at greater risk of progression to severe symptoms, regardless of vaccination status,” said Pfizer CEO Albert Bourla.

The FDA has 60 days to accept the application and up to 10 months to conduct a review before making a decision. If approved, that could mean an exponential increase in sales of Paxlovid. JPMorgan Chase estimates that the drug could generate about $26 billion in sales this year.

But it hasn’t been all smooth sailing for Paxlovid, the more popular of the two oral COVID-19 drugs with EUAs. Merck and Ridgeback’s Lagevrio (molnupiravir) is the other.

Earlier this month, Pfizer halted a sizable phase 2/3 trial when Paxlovid showed limited efficacy in reducing the risks of symptoms for standard-risk patients (DID, June 16).

And new lab studies have shown COVID-19 can mutate in ways that make it less susceptible to Paxlovid.

Also, several studies have found a small percentage of infected people who receive the normal five-day course of the drug feel better initially, but then their symptoms return.

And Paxlovid hasn’t been easy to get. For its initial rollout, doctors in the U.S. were only able to write 40,000 or fewer prescriptions per week through mid-April, after the drug got its EUA in December of last year. Prescriptions have since surged to more than 160,000 per week, according to the U.S. Centers for Disease Control and Prevention (CDC).

In May, the White House issued a fact sheet calling on all sites dispensing oral antivirals to collect robust demographic data on people getting prescriptions for COVID-19 therapeutics, as there is no broad data on who is being prescribed Paxlovid beyond state-level totals.

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 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.

Paxlovid is approved or authorized for conditional or emergency use in more than 65 countries. As of the end of May 2022, Pfizer had shipped more than 12 million treatment courses of Paxlovid to nearly 40 countries, the company said.

The U.S. has committed to purchasing 20 million courses of Paxlovid. — Suz Redfearn