An advisory group for the Food and Drug Administration (FDA) has voted to recommend Merck's COVID-19 antiviral pill for infected adults at high risk for severe coronavirus illness, hospitalization or death.
The panel narrowly endorsed Merck's five-day oral treatment in a 13-10 vote on Tuesday.
The advisers recommended the FDA authorize the pill, developed with Ridgeback Biotherapeutics, for adult patients enduring mild to moderate COVID-19 who face a higher risk of serious illness, including due to underlying health conditions.
The drug manufacturer filed for an emergency use authorization last month after its study suggested molnupiravir reduced the risk of hospitalization by 50 percent. But updated data from Friday showed a 30 percent reduction in hospitalizations among more participants.
The close vote came as experts considered concerns about the decreased risk reduction in Merck's updated data as well as the risks the drug could present for pregnant people.
Several who backed the pill for high-risk infected adults pointed to the ongoing state of emergency amid COVID-19 and the limited treatments for the virus.
"I see this as an incredibly difficult decision," the committee's chairperson, Lindsey Baden, said. "There are many, many more questions than answers."
"But I can see scenarios where there are benefits and therefore having this available for those scenarios makes sense to me," he added.
Those who voted against the endorsement cited a "modest" effectiveness shown in the data.
Approval of these pills could expand accessibility of at-home COVID-19 treatments, pending FDA authorization and Centers for Disease Control and Prevention approval. The U.S. has already agreed to buy 3.1 million courses of the drug, with the option to purchase more.
Antiviral COVID-19 drugs have been considered a potential game changer in the pandemic since all current drugs require an injection or IV. Other pills are in development, including Paxlovid from Pfizer, which requested FDA authorization earlier this month.
The vote comes after the FDA released its review of Merck's data on the drug last week that concluded molnupiravir's effectiveness but raised concerns about its effects on pregnant people.
Merck representatives recommended during the meeting that people who are pregnant or breastfeeding do not take the pills due to potential risks, including possible toxicity and birth defects.
The pharmaceutical company suggested women of childbearing age use contraception while receiving molnupiravir. Merck plans to launch a pregnancy surveillance program to further track the drug's effects on pregnant people.
Several advisers supported a warning for pregnant people not to take the drug, and some suggested requiring pregnancy testing for patients before they receive the drug.
Merck is also not currently seeking authorization for the pill to be administered to children.
Some experts expressed worries that the drug, which inserts small errors into the virus's genetic code to prevent replication, could spark the virus to mutate into more dangerous strains, although the FDA considers the issue a "theoretical" concern.
Merck's pill would not function as a preventative treatment, as it would be administered to already infected individuals to avoid worse outcomes.
The treatment is not designed to replace vaccinations, as COVID-19 vaccines would still be needed to stop infection in the first place. Merck did not study the drug's effects among vaccinated people.
The advisers' decision also comes as anxiety has mounted over the World Health Organization's most recent variant of concern: the omicron strain.
A Merck representative told the FDA in the meeting that the company has not tested molnupiravir against the omicron variant, but they expect the pill to remain effective against the strain.
Updated at 5:36 p.m.