The Food and Drug Administration on Thursday authorized Merck's oral antiviral pill to treat COVID-19, the second such pill to be cleared for use in the United States.

What You Need To Know

  • The FDA authorized Merck's oral antiviral pill to treat COVID-19 on Thursday

  • The move comes one day after federal health regulators authorized Pfizer's COVID-19 pill

  • The Biden administration reached a deal with Merck to purchase a total of 3.1 million doses of Merck's pill, known as Molnupiravir

  • Molnupiravir is not recommended for use in patients who are pregnant, according to Merck, and the FDA says the pill will carry a warning against use during pregnancy

The move comes one day after federal health regulators authorized Pfizer's COVID-19 pill, and weeks after a panel of advisers to the FDA narrowly voted to approve the Merck pill.

Molnupiravir, a joint effort by Merck and Ridgeback Biotherapeutics, cut the risk of hospitalization and death in high-risk patients by 30% in a clinical trial, but Pfizer's pill, Paxlovid, slashed death and hospitalization rates by 90%, potentially making it a more attractive option for patients.

The drug inserts errors into the virus' genetic code to slow its ability to reproduce, which has raised some concerns that it could cause mutations to the virus, as well as in human fetuses. However, scientists with the FDA dismissed these concerns, calling the variant risk largely theoretical due to the short course of taking the drug.

Merck's pill was authorized for patients 18 and older who are at high risk of severe disease from COVID-19 "for whom alternative COVID-19 treatment options authorized by the FDA are not accessible or clinically appropriate."

"Today’s authorization provides an additional treatment option against the COVID-19 virus in the form of a pill that can be taken orally," Patrizia Cavazzoni, M.D., director of the FDA’s Center for Drug Evaluation and Research, said in a statement. "Molnupiravir is limited to situations where other FDA-authorized treatments for COVID-19 are inaccessible or are not clinically appropriate and will be a useful treatment option for some patients with COVID-19 at high risk of hospitalization or death."

"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," Cavazzoni added.

In November, the Biden administration reached a deal with Merck to purchase 1.4 million additional doses of molnupiravir, bringing their order to a total of 3.1 million courses of the pill, a deal valued at roughly $2.2 billion, between authorization and early 2022. The U.S. government also has the option to buy 2 million more doses. The U.S. has secured 10 million doses of Pfizer's pill.

"The FDA Emergency Use Authorization of molnupiravir is an important milestone in the fight against COVID-19, and adds to Merck’s legacy of bringing forward innovative medicines that both address the world’s greatest health threats and help save lives," Robert Davis, Merck's CEO, said in a statement.

"Because we recognized the promise of molnupiravir early, Merck invested at risk and we are executing an unprecedented global access strategy so that molnupiravir, now authorized, can be available to patients here in the U.S. and all around the world more quickly and more equitably than has ever been accomplished before," he added.

Officials at Merck say that hundreds of thousands of courses of the treatment will be available in the U.S. in the next few days, with a million more on the way in the next few weeks.

The U.S. will pay about $700 for each course of Molnupiravir, which requires patients to take four pills twice a day for five days. A review by Harvard University and King’s College London estimated it costs about $18 to make each 40-pill course of treatment.

Molnupiravir is not recommended for use in patients who are pregnant, according to Merck, due to a risk of fetal harm when administered to pregnant individuals based on animal reproductive studies. Per the company, the pill has not been studied in pregnant individuals "to evaluate the risk of major birth defects, miscarriage or adverse maternal or fetal outcomes."

As such, molnupiravir will carry a warning against use during pregnancy. Women of childbearing age should use birth control during treatment and for a few days after while men should use birth control for at least three months after their final dose, the FDA said.

The FDA also said that the drug should not be used in patients under 18 because it may affect bone and cartilage growth.

The Associated Press contributed to this report.