FDA Panel Gives Support to Merck's COVID Antiviral Pill

TUESDAY, Nov. 30, 2021 (HealthDay News) -- A U.S. Food and Drug Administration advisory panel on Tuesday voted narrowly to recommend emergency use of Merck's new antiviral pill to help prevent severe COVID-19 in high-risk patients.

By a 13-10 count, the panelists recommended molnupiravir for use by older COVID-19 patients or those who have medical conditions that make them especially susceptible to severe illness.

The decision clears the way for the FDA to approve the drug for such use within days, and it might be available to patients generally before year's end, according to the New York Times.

The FDA doesn't have to follow its advisory panels' recommendations, but it typically does.

The FDA may also soon approve an antiviral pill from Pfizer that appears to be significantly more powerful than Merck's pill, showing 89% efficacy in reducing hospitalizations and deaths among COVID-19 patients.

The panel's approval of molnupiravir wasn't guaranteed. There were already two strikes against the pill: Fresh data from Merck shows that molnupiravir isn't as effective as first reported; and FDA documents prepared for the panel meeting show the pill may pose a risk of birth defects.

Merck said Friday that final study results showed the pill reduced hospitalization and death by 30% among infected adults, which is much lower than the 50% reduction first announced by the company.

And an FDA safety review noted that animal studies suggest that high doses of the drug could trigger birth defects.

U.S. health officials have said they are considering banning the use of molnupiravir in pregnant women and are weighing other safeguards, including recommending contraceptives for some patients taking the medication, the Associated Press reported.

Why a risk of birth defects? Merck's drug disables the coronavirus by inserting tiny errors into its genetic code to stop the pathogen from reproducing. That mechanism of action has raised concerns that the drug could cause mutations in human fetuses or even spur more virulent strains of the virus.

Still, given the troubling emergence of the new Omicron variant, the FDA was widely expected to authorize emergency use of molnupiravir, which is already authorized for emergency use in the United Kingdom, the AP reported.

Experiments need to be conducted to see how well the pill works at disabling the Omicron variant, but there is reason to believe they would remain effective even if the new variant can evade vaccines, theTimes reported.

Omicron has more than 30 mutations on its so-called spike protein, and some of those mutations may make it hard for vaccine-produced antibodies to attack the virus. But Merck's antiviral pills do not target the spike protein. Instead, they weaken two proteins involved in the virus' replication machinery. Omicron carries only one mutation in each of those proteins, and neither looks as if it would stop the pills from doing their jobs, the Times reported.

In a presentation to the expert panel, Merck executive Daria Hazuda said molnupiravir's activity makes it likely to work against any new variants.

If molnupiravir is authorized in the United States, the Biden administration has ordered enough courses of treatment, at about $700 per person, for 3.1 million people, the Times reported. The treatment is to be given within five days of the start of symptoms and is taken as 40 pills over five days.

More information

Visit the U.S. Food and Drug Administration for more on COVID treatments.

SOURCES: Associated Press; The New York Times

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