The Food and Drug Administration gave full approval Thursday Pfizers The antiviral Covid pill Paxlovid for adults who are at high risk of becoming seriously ill with the virus.
Paxlovid is specifically recommended for the treatment of mild to moderate Covid in adults over the age of 50 and in people suffering from certain medical conditions that put them at higher risk of ending up in hospital or dying from Covid.
This includes people with diabetes, heart disease, cancer, or a compromised immune system.
Up to three quarters of adults in the US are at risk of developing serious illness from Covid.
“Today’s approval demonstrates that Paxlovid meets the agency’s strict standards for safety and efficacy and that it remains an important treatment option for people at high risk of developing severe COVID-19 disease, including those with prior immunity,” says 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 as part of an emergency use authorization for high-risk individuals ages 12 and older. Under this designation, the FDA quickly approved the treatment based on preliminary clinical trial data.
The FDA’s recent decision means there is now extensive clinical data suggesting Paxlovid is safe and effective.
The treatment consists of two drugs: nirmatrelvir, which blocks a key enzyme that the Covid virus needs to replicate, 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 tool to vaccination that can help high-risk Americans manage their Covid infections and ultimately save lives.
FDA researchers estimated, based on Covid rates in January, that Paxlovid “could save 1,500 lives and avert 13,000 hospitalizations each week” in the United States.
However, it’s unclear how many people will receive the treatment later this year.
According to the Department of Health and Human Services, around 4 million doses of Paxlovid are available free of charge from pharmacies and healthcare providers nationwide. In addition, the US government has a stockpile of 9.6 million doses.
Once that stock is depleted, 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 currently costs around $530 per course.
Pfizer, whose sales of Paxlovid rose to nearly $19 billion in 2022, expects sales of the drug to fall 58% in 2023.
In March, an independent FDA advisory panel recommended the treatment based on three clinical trials conducted by Pfizer.
One study looked at high-risk adults who were unvaccinated and had no prior Covid infection.
This study found that Paxlovid reduced the risk of hospitalization or death by 86% in adults treated within five days of the first symptoms and by 89% in adults treated within three days, as from a review of the company’s data by the FDA.
The study found no major safety concerns, the review said, although the agency identified 137 drugs that can cause serious side effects when they interact with Paxlovid.
The FDA said the most common drugs causing safety issues are immunosuppressive drugs, which are commonly used to treat HIV and organ transplant patients.
The FDA’s Office of Surveillance and Epidemiology recorded 271 reports of serious adverse events potentially related to drug-drug interactions with Paxlovid at the end of January, including 147 hospitalizations and six deaths.
FDA officials said these events could potentially be avoided by adjusting dosages of certain drugs, increasing patient monitoring, and ensuring product labeling informs prescribers and patients about potential drug interactions.
Another area of concern for some doctors is Paxlovid’s “rebound cases.” This is when patients receiving the treatment find their Covid symptoms come back or test positive soon after their initial recovery.
Reports of these cases emerged shortly after Paxlovid was launched.
Both President Joe Biden and his former chief medical adviser, Dr. Anthony Fauci appear to have recovered from Covid after taking the antiviral cocktail but tested positive again shortly after recovering.
An FDA review of Pfizer’s clinical trials found that overall rebound rates ranged from 10% to 16%, “with no evidence of a greater or moderate symptom rebound rate” in patients receiving Paxlovid compared to patients receiving placebo received.
According to the FDA review, these results also held true regardless of patients’ risk for serious disease or whether the Omicron variant or an earlier viral strain was dominant.
Correction: There are approximately 4 million doses of Paxlovid available in pharmacies and healthcare providers nationwide in the United States. In an earlier version of this story, the number was given incorrectly.