This handout photo obtained May 26, 2021 courtesy of Merck & Co,Inc. shows capsules of the investigational antiviral pill Molnupiravir
The US Food and Drug Administration (FDA) on Thursday authorized Merck’s Covid pill for high-risk adults, a day after green lighting a similar but more effective drug by Pfizer amid a winter surge of cases driven by Omicron.
While vaccines and boosters remain the foremost tools in the fight against the pandemic, experts have welcomed the addition of the new oral treatments, which inhibit the virus’ ability to replicate and should withstand variants.
The pill developed by Merck, called molnupiravir, is taken within five days of symptom onset and was shown in a trial of 1,400 participants to reduce Covid hospitalizations and deaths by 30 percent among at-risk people.
The US has paid $2.2 billion for 3.1 million courses of Merck’s treatment, and $5.3 billion for 10 million courses of Pfizer’s.
Pills that can be picked up at pharmacies following a prescription should be a major boost to health care systems.
Because the pills do not target the ever-mutating spike protein that dots the virus’ surface, they should be variant proof. The companies have said early lab testing against Omicron have borne this out.
Still, the major difference in the two treatments’ efficacy has raised questions about why patients or doctors would seek Merck’s capsule, which is known as MSD outside the US and Canada.
For example, Pfizer’s treatment, Paxlovid, can cause adverse reactions if mixed with certain other medications, and isn’t recommended for people with severe kidney or liver impairment.
The FDA has not authorized Merck’s pill for people under 18 because it may affect bone and cartilage growth.
Independent experts convened by the FDA narrowly voted in favor of authorizing molnupiravir in early December. Several who voted “no” highlighted these potential risks.
Eight capsules of molnupiravir are taken orally for five days, for a total of 40 capsules.
The drug has previously been authorized in Britain and Denmark.
FDA scientist John Farley explained that in the case of Pfizer, the benefit-to-risk balance was more clear and the agency did not feel the need for external input.