Merck says the U.S. will buy 1.4 million doses of its COVID-19 antiviral pill

Merck & Co. said the U.S. committed to buy 1.4 million courses of its COVID-19 pill developed with Ridgeback Biotherapeutics LP for about $1 billion, bringing the country’s total to 3.1 million.

The purchases are contingent on Food and Drug Administration clearance of the oral antiviral, called molnupiravir, Merck said Tuesday in a statement, and the U.S. has the ability to buy 2 million more courses. Merck shares fell 0.4% as of 9:56 a.m. in New York.

Pills from Merck and Pfizer Inc. have both shown effectiveness in keeping high-risk patients out of hospitals, and have been hailed as key tools in reversing the course of the pandemic. The U.S. order is a positive sign for Merck after Pfizer’s results appeared to be stronger in preventing hospitalization and deaths.

While Pfizer’s Paxlovid was 89% effective in preventing high-risk patients from worsening, Merck’s trial showed 50% efficacy. Still, comparisons of the two drugs still aren’t clear, as there may have been baseline differences in the two companies’ study populations, Sam Fazeli, a Bloomberg Intelligence analyst, said Monday in a research note.

Merck has said it will produce 10 million courses of its pill this year. Assuming those sell for $700, the price the U.S. has paid up to this point, that represents $7 billion in potential sales, Fazeli said in the note.

Resistance is always a concern with antivirals, and doctors may eventually use COVID pills together, both to boost effectiveness and reduce the risk that strains will emerge that can overcome the drugs.

“Antiviral therapy using just one drug has a risk of inducing drug resistance,” Fazeli said in the note. “One way of reducing this threat is to use drug combinations, as long as safety isn’t an issue.”