The Food and Drug Administration on Thursday promised full approval from Pfizer Covid antiviral pill, Paxlovid, for adults who are at high risk of becoming seriously ill from the virus.
Paxlovid is specifically advised for the treatment of mild to moderate Covid in adults over 50 years of age and those suffering from certain medical conditions putting them at greater risk of ending up in hospital or dying from Covid.
So do people with diabetes, heart disease, cancer or a weak immune system.
As much as three quarters of adults in the US are at risk of severe Covid.
“Today’s approval demonstrates that Paxlovid meets the agency’s rigorous standards for safety and effectiveness, and that it remains an important treatment option for people at high risk of progression to severe COVID-19, including those with prior immunity,” Dr. Patrizia Cavazzoni, director of the FDA’s Center for Drug Evaluation and Research, said in a press release.
The FDA first made Paxlovid available in December 2021 under authorization for emergency use for high-risk individuals ages 12 and older. Under that designation, the FDA quickly approved the treatment based on preliminary clinical trial data.
The latest FDA decision means there is now extensive clinical data indicating that Paxlovid is safe and effective.
The treatment consists of two drugs: nirmatrelvir, which blocks an important enzyme needed to replicate the Covid virus, and ritonavir, which boosts the first drug’s ability to fight the infection.
Both Pfizer and the FDA view the treatment as an important adjunct to vaccination that could help high-risk Americans manage their Covid infections and ultimately save lives.
FDA investigators estimate, based on Covid numbers in January, that Paxlovid “could save 1,500 lives and prevent 13,000 hospitalizations each week” in the US.
But it’s unclear how many people will receive the treatment later this year.
There are about 4 million doses of Paxlovid available at pharmacies and healthcare providers nationwide for free, according to the Department of Health and Human Services. In addition, the US government has a stockpile of 9.6 million doses.
Once that stock runs out, the government expects to shift distribution of Paxlovid to the commercial market.
That means Pfizer will sell Paxlovid directly to healthcare providers at a price the company hasn’t disclosed. Paxlovid costs approx $530 per course now.
Pfizer, which saw sales of Paxlovid climb to nearly $19 billion by 2022, expects revenue from the drug to drop 58% in 2023.
In March, an independent FDA panel of advisors recommended the treatment based on three Pfizer clinical trials.
One trial examined high-risk adults who had not been vaccinated and had no previous Covid infection.
That study found that Paxlovid reduced the risk of hospitalization or death by 86% in adults treated within five days of their first symptoms, and by 89% in those treated within three days, according to an FDA review of the data. from the company.
No major safety concerns were identified during the study, the review said, though the agency flagged 137 medications that could lead to serious side effects if they interact with Paxlovid.
The FDA said the most common drugs causing safety concerns were immunosuppressants, commonly used to treat HIV and organ transplant patients.
The FDA’s Office of Surveillance and Epidemiology recorded 271 reports of serious adverse events possibly related to drug interactions with Paxlovid at the end of January, including 147 hospitalizations and six deaths.
FDA staff said these events could potentially be avoided by adjusting the dose of certain medications, improving patient monitoring and making sure product labels inform prescribers and patients about potential drug interactions.
For some doctors, another concern is Paxlovid’s “rebound cases.” That’s when patients undergoing the treatment see their Covid symptoms return or test positive shortly after initially recovering.
Reports of those cases surfaced not long after Paxlovid first hit the market.
Both President Joe Biden and his former chief medical advisor Dr. Anthony Fauci appeared to have recovered from Covid after taking the antiviral cocktail, but tested positive again shortly after recovery.
An FDA review of Pfizer’s clinical trials found that overall rebound rates ranged from 10% to 16%, “with no evidence of a higher rate of symptom rebound or moderate symptom rebound” in patients receiving Paxlovid compared to patients receiving placebo .
Those results also held regardless of the patient’s risk of serious disease, whether the omicron variant or an earlier strain of the virus was dominant, according to the FDA review.
Correction: The US has approximately 4 million doses of Paxlovid available from pharmacies and healthcare providers nationwide. An earlier version of this story misrepresented the figure.