Merck’s filing comes less than two weeks after the drugmaker showed molnupiravir lowered the risk of hospitalization or death by roughly 50% in a Phase 3 trial, a result so convincing that trial monitors stopped testing earlier than expected.
The finding marked a potential turning point in the pandemic, the first time an oral drug had demonstrated the ability to prevent COVID-19’s worst health outcomes. The need for such an easy-to-take treatment remains high, with roughly 44% of the U.S. population still unvaccinated, according to data from the Centers for Disease Control and Prevention.
Though Merck and Ridgeback’s drug appears less effective in clinical testing than the infusible or injectable antibody treatments from Regeneron and others, it’s also much more convenient, which should make treatment easier to administer to patients before their symptoms progress. Antibody drugs, up until recently, had been underutilized because of logistical issues. Some analysts expect Merck’s drug to generate more than $5 billion next year.
But Merck’s pill nonetheless faces questions. The drug, for instance, wasn’t tested in people who have been vaccinated, leaving it unclear as to whether people with so-called breakthrough infections will be eligible for treatment. Merck, in its press release, didn’t say whether vaccine recipients are included in its application.
Additionally, rival experimental treatments from Pfizer, Atea Pharmaceuticals and partner Roche, and Appili Therapeutics could soon match or top molnupivarir. All of them are in advanced testing, with results expected soon.
And though Merck has said the drug was safe in clinical testing, with side effect rates comparable between those who had received molnupiravir or placebo, there are other concerns. Because of how molnupiravir works, the drug has the potential to be mutagenic, or incorporate into the DNA of human cells. (Merck, for its part, has said the company hasn’t observed any evidence of mutagenicity in the more than 1,000 patients who have been treated with molnupiravir.)
“We tend to think this risk is overblown … and we think [the] drug has a good shot at approval on this data,” Evercore ISI analyst Umer Raffat recently wrote.
Merck is still testing the drug as a preventive treatment for people who have recently been exposed to infection by a household contact — another setting in which antibody drugs have proven effective. Results from that study are expected by the end of the year.
The drugmaker is also planning for a global launch of molnupiravir, with contracts in place with generic developers to make the treatment available in over 100 low- and middle-income countries.