The FDA has authorized pills to treat COVID-19, replenishing the tool kit of treatments against Omicron

• The FDA has authorized pills to treat COVID-19, a milestone in the fight against the pandemic.
• The OKs for Pfizer and Merck's pills come as Omicron is causing a surge in cases.

The Food and Drug Administration has authorized pills to treat COVID-19.

The agency issued emergency approval on Wednesday for an antiviral developed by Pfizer. The FDA's authorization allows high-risk people ages 12 or older to receive the pills.

The agency went on to authorize Merck's antiviral pill on Tuesday for use in high-risk people 18 or older who have been diagnosed with COVID-19.

For both pills, people have to start treatment within five days of showing symptoms. Both treatments are given as five-day regimens, with Merck's being 40 pills and Pfizer's being 30 pills.

"As new variants of the virus continue to emerge, it is crucial to expand the country's arsenal of COVID-19 therapies using emergency use authorization, while continuing to generate additional data on their safety and effectiveness," Dr. Patrizia Cavazzoni, the director of the FDA's Center for Drug Evaluation and Research, said in a statement on Thursday.

A new way to combat COVID-19

Doctors have said they were excited to have an easy-to-use option to treat the illness before people require hospitalization. The only other drugs authorized to treat nonhospitalized COVID-19 patients are monoclonal antibodies, which are typically delivered via an IV infusion.

The rise of the Omicron variant, which is causing a new wave of cases across the US, has weakened several of those antibody treatments. The variant's mutations have been found in laboratory testing to render some of those drugs, particularly the ones from Regeneron Pharmaceuticals and Eli Lilly, far less effective.

Dr. Kavita Patel, a primary-care physician in Washington, DC, and former White House health-policy director, said she was eager to start using these pills to treat certain patients, especially because of the logistical challenges with antibody drugs.

"It is just a beast to try to get people monoclonals," Patel told Insider.

Experts also anticipate the antiviral pills will work equally well against Omicron and future variants because the pill doesn't target the virus' spike protein. The spike protein — used by the virus to latch on to human cells — is the primary target for most vaccines and antibody drugs, and the Omicron variant has more than 30 mutations on that protein.

"Today's authorization of PAXLOVID represents another tremendous example of how science will help us ultimately defeat this pandemic, which, even two years in, continues to disrupt and devastate lives across the world," Pfizer CEO Albert Bourla said in a statement on Wednesday.

Safety and efficacy concerns weaken the impact of Merck's pill

The two pills are not equal in their effectiveness and safety. Merck's drug was far less effective in a late-stage study and has also raised safety concerns that don't impact Pfizer's pill.

Overall, Merck's drug reduced hospitalizations and deaths by 30%, while Pfizer's drug — tested in a similar patient population — reduced hospitalizations and deaths by 88% compared to dummy pills. Each study enrolled roughly 1,400 unvaccinated people who recently got COIVD-19, randomly giving them either the experimental pills or a placebo. All volunteers were considered at high risk of developing severe disease.

The FDA convened a group of independent experts to debate and vote on Merck's drug on November 30. That panel narrowly voted 13-10 in favor of authorization, with several committee members expressing concerns with the safety risks of Merck's drug.

Merck's pill is a nucleoside, a type of antiviral that intentionally inserts errors into the copying process of a virus. While that obstructs viral replication, it also carries the theoretical risk the drug could interact and mutate human cells. That has some scientists concerned.

In particular, several experts on the FDA panel were concerned in offering this drug to pregnant people, given the potential risk to fetuses. The FDA said on Thursday that molnupiravir is not recommended for pregnant people.

"As a woman of child-bearing age, I don't think I would want to take this drug, not knowing the effects it could have on my unborn child," said Roblena Walker, the panel's consumer representative who runs a nonprofit public-health organization.

Pfizer's pill doesn't raise those same concerns because Paxlovid acts in a different way. The drug is a protease inhibitor designed to block an enzyme that plays a key role in the virus' copying process. It's given with a low dose of another antiviral, ritonavir, to help Paxlovid last longer in the body. The FDA didn't have its advisory committee meet to consider Pfizer's drug.

Pfizer and Merck stands to make billions off the new drugs

The greenlight will trigger a windfall for Pfizer, as the US government signed supply deals this year that were contingent on an FDA authorization.

Last month, the US agreed to pay $5.3 billion for 10 million treatment courses of Paxlovid. In a Wednesday press release, Pfizer said it planned to increase total production of the drug from 80 million treatment courses to 120 million courses next year. In total, the US will pay Merck $2.2 billion for enough pills to treat 3.1 million people.

Wall Street analysts expect Pfizer's pill to turn into one of the industry's bestselling medicines in 2022. Analysts at Mizuho and SVB Leerink both forecast Paxlovid sales of $24 billion next year.

This article was initially published on Wednesday and has been updated on Thursday after the FDA authorized Merck's antiviral pill molnupiravir.