Britain becomes the first nation to authorize Merck’s COVID-19 pill

Merck corporate headquarters in Kenilworth, N.J.
So far Merck’s COVID-19 pill is the only one shown to successfully treat the disease.
(Seth Wenig / Associated Press)

Britain has granted conditional authorization to Merck’s COVID-19 pill — the only one so far shown to successfully treat the disease — becoming the first nation to OK the treatment, although it was not immediately clear how quickly the drug would be available.

The pill was licensed for adults 18 and older who have tested positive for COVID-19 and have at least one risk factor for developing severe disease, such as obesity or heart disease. The drug, known as molnupiravir, is intended to be taken twice a day for five days by people at home with mild to moderate COVID-19.

An antiviral pill that reduces symptoms and speeds recovery could prove groundbreaking, easing caseloads on hospitals and helping to curb outbreaks in poorer countries with fragile health systems. It would also bolster the two-pronged approach to the pandemic: treatment, by way of medication; and prevention, primarily through vaccinations.


Molnupiravir is also pending review with regulators in the U.S., continental Europe and elsewhere. The U.S. Food and Drug Administration announced last month that it would convene a panel of independent experts to scrutinize the pill’s safety and effectiveness in late November.

Initial supplies will be limited. Merck has said it can produce 10 million treatment courses through the end of the year, but much of that supply has already been purchased by governments worldwide.

In October, British officials announced they had secured 480,000 courses of molnupiravir and expected thousands of vulnerable Britons to have access to the treatment this winter via a national study.

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“Today is a historic day for our country, as the U.K. is now the first country in the world to approve an antiviral that can be taken at home for COVID-19,” said Health Secretary Sajid Javid.

“We are working at pace across the government and with the NHS [National Health Service] to set out plans to deploy molnupiravir to patients through a national study as soon as possible,” Javid said in a statement. Doctors said the treatment would be particularly significant for people who do not respond well to vaccination.


Merck and its partner, Ridgeback Biotherapeutic, have requested clearance for the drug with regulators around the world to treat adults with mild to moderate COVID-19 who are at risk for severe disease or hospitalization. That’s roughly the same group targeted for treatment with infused COVID-19 antibody drugs, the standard of care in many countries for patients who don’t yet require hospitalization.

For the record:

6:04 a.m. Nov. 4, 2021A previous version of this story misstated when Merck issued findings regarding its COVID-19 pill. They were announced in September, not last month.

Merck announced preliminary results in September showing that its drug cut hospitalizations and deaths by half among patients with early COVID-19 symptoms. The results have not yet been peer-reviewed or published in a scientific journal.

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The company also did not disclose details on molnupiravir’s side effects, except to say that rates of those problems were similar between people who got the drug and those who received dummy pills.

The drug targets an enzyme that the coronavirus uses to reproduce itself, inserting errors into its genetic code to slow its ability to spread and take over human cells. That genetic activity has led some independent experts to question whether the drug could potentially cause mutations leading to birth defects or tumors.

Britain’s Medicines and Healthcare Products Regulatory Agency said molnupiravir’s ability to interact with DNA and cause mutations had been studied “extensively” and that it was not found to pose a risk to humans.

“Studies in rats showed that [molnupiravir] may cause harmful effects to the unborn offspring, although this was at doses which were higher than those that will be given to humans, and these effects were not observed in other animals,” the agency said in an email.

In company trials, both men and women were instructed either to use contraception or abstain from sex. Pregnant women were excluded from the study. Merck has stated that the drug is safe when used as directed.

Molnupiravir was initially studied as a potential flu therapy with funding from the U.S. government. Last year, researchers at Emory University decided to repurpose the drug as a potential COVID-19 treatment. They then licensed the drug to Ridgeback and its partner, Merck.

Last week, Merck agreed to allow other drugmakers to make its COVID-19 pill, in a move aimed at helping millions in poorer countries get access. The Medicines Patent Pool, a United Nations-backed group, said Merck would not receive royalties under the agreement for as long as the World Health Organization deems COVID-19 to be a global emergency.

But the deal was criticized by some activists for excluding many middle-income countries capable of making millions of treatments, including Brazil and China.

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Still, experts commended Merck for agreeing to widely share its formula and promising to help any companies that need technological help in making their drug — something no COVID-19 vaccine producers have agreed to.

“Unlike the grotesquely unequal distribution of COVID-19 vaccines, the poorest countries will not have to wait at the back of the queue for molnupiravir,” said Dr. Mohga Kamal-Yanni, a senior health advisor to the People’s Vaccine Alliance. Less than 1% of the world’s COVID-19 vaccines have gone to poor countries, and experts hope easier-to-dispense treatments will help them curb the pandemic.

Merck previously announced licensing deals with several Indian generic drugmakers to make lower-cost versions of the drug for developing countries.

The U.S. reportedly paid roughly $700 per course of molnupiravir, for about 1.7 million treatments. Merck says it plans to use a tiered pricing strategy for developing countries. A review by Harvard University and King’s College London estimated that the drug costs about $18 to make.

While other treatments have been cleared to treat COVID-19, including steroids and monoclonal antibodies, those are administered by injection or infusion and are mostly for hospitalized patients.