Merck & Co.'s Covid-19 pill was cleared by US regulators Thursday, giving high-risk patients a second at-home treatment just as the Omicron variant is causing cases to surge around the country.
The drug, Molnupiravir, received emergency authorisation on the heels of Pfizer Inc.'s Covid pill being cleared Wednesday. The FDA said Merck's drug is not recommended for use in pregnant people.
The two treatments hold the potential to keep a sharp rise in infections from overwhelming U.S. hospitals. Molnupiravir, developed by Merck with partner Ridgeback Biotherapeutics LP, is intended to be used at home to treat Covid in people 18 and older at risk of developing severe illness. A study showed it reduced the risk of hospitalisation or death among adults with mild to moderate disease by 30%.
Molnupiravir works by introducing errors in genetic material to ultimately stop the virus's replication, but it may affect growing human cells. Merck has established a pregnancy surveillance programme for the drug and said men and women should use contraception while taking Molnupiravir, if they're having sex that might result in pregnancy.
The US has signalled a preference for Pfizer's pill, ordering 10 million courses along with 3 million of Merck's. However, the Merck pill will be available more widely early on. The US expects to receive its full order of three million courses of Merck's drug by the end of January. Pfizer's will arrive more slowly, with 10 million coming by July.
Jeff Zients, who serves as President Joe Biden's Covid-19 response coordinator, said Wednesday that the US would use Merck's pill however the FDA advises. "We will follow the FDA's lead," he said.
During a call with journalists Thursday, John Farley, the FDA's director of the Office of Infectious Diseases, said Molnupiravir posed a "challenging benefit-risk consideration," which is why an advisory committee meeting was convened last month to discuss the drug. With Pfizer's drug this was not the case, Farley said.
The language on Molnupiravir's label says it should be used when other treatment options are not accessible or clinically appropriate, which led to questions about whether the agency prefers Pfizer's drug. The FDA said they are not necessarily recommending Pfizer drug over Merck's.
There may be situations in which Merck's drug might be more appropriate for a patient than Pfizer's, said Patrizia Cavazzoni, director of the FDA's Center for Drug Evaluation and Research, adding that it is up to physicians to make those determinations.
"It is a question of availability, but it's also a question of appropriateness of the patient for the specific drug." Ms Cavazzoni said.
Merck's shares were little changed as of 12:41 p.m. in New York.
In November, several concerns were raised when the panel of outside advisers to the FDA debated whether Merck's drug was safe for wide use. Some expressed worry that it could lead to mutations that might make the virus more dangerous or transmissible, or that it could pose risks for pregnant people, and that its low efficacy in the clinical trial meant its risks outweighed its benefits. Ultimately, a divided panel voted to back the treatment by a narrow margin.
Merck has said Molnupiravir doesn't pose long-term risks and touted how well it worked in preventing death in patients.
"This is a drug that when you look at it, an antiviral, in the middle of a pandemic, that reduces mortality by 90%," said Dean Li, president of Merck's research division. "In the history of respiratory viruses and other pandemics there's never been drugs that can do that, and we have one of those and we are ready to supply the world."
Currently, patients who could become seriously ill with Covid are given infused drugs in hospitals or clinics, whereas a five-day course of Molnupiravir can be taken at home.
The U.S. has already reached a contract with Merck for $1.2 billion which means a five-day course will cost the government about $700 per patient. Molnupiravir will give Merck about $2.5 billion in global revenue next year, according to an estimate from Airfinity Ltd. Merck said it expects to produce 10 million courses of the treatment by the end of the calendar year, with at least 20 million courses to be produced in 2022.
Meanwhile, Pfizer is already pulling in huge profits from its Covid vaccine and expected to reap about $17 billion from sales of Paxlovid in 2022, the London-based data firm said.
Government officials have said they expect to have 400,000 courses of Merck's treatment available initially.
