Pfizer asked the Food and Drug Administration on Tuesday to authorize its experimental Covid-19 antiviral treatment, Paxlovid.
The treatment was shown in clinical trials to reduce the risk of hospitalization and death by 89 percent in people at high risk of severe illness, the company reported this month, although the full data haven't been made public for scientists to review.
Experts say an antiviral pill for Covid would have a major impact on the coronavirus pandemic by making treatment available at home, without injections or IVs.
Pfizer's treatment consists of three pills taken twice daily for five days. It is meant to be given early, within three to five days of the onset of symptoms.
The company requested authorization of the treatment only for unvaccinated people at this time, said Jerica Pitts, a Pfizer spokesperson. Vaccinated people weren't included in the trial, she said. Vaccinated people, including those with an underlying medical condition, are participants in other trials which are still underway, Pfizer said in a later email. That data will eventually be submitted to regulators, although it is up to the FDA and the CDC to determine how the drugs are labeled for use.
An additional study using the antiviral treatment to prevent Covid in adults who live in the same household as someone with a confirmed symptomatic infection began in September.
Paxlovid works by preventing the coronavirus from replicating inside cells. It combines two antivirals: an experimental compound called PF-07321332 and an existing drug called ritonavir, which is used in HIV treatments.
Pfizer said in a statement that the treatment is safe and that side effects were mild, occurring at the same rate as in the placebo group. It didn't detail what the side effects were.
Pfizer announced earlier Tuesday that it had signed a deal with a U.N.-backed group to allow other drug manufacturers to make the pill, which could make it available to more than half of the world's population.
Pfizer isn't the first company to ask the FDA to authorize an antiviral pill for Covid; in October, Merck and its partner, Ridgeback Biotherapeutic, applied for authorization of an antiviral. An FDA advisory committee will review the request on Nov. 30.