FDA authorizes Merck pill molnupiravir to treat COVID-19

One day after authorizing Pfizer's COVID-19 treatment pills, the US Food and Drug Administration on Thursday cleared a second pill -- this one from Merck -- for treating the virus under the agency's emergency use authorization. The FDA advised taking Merck's molnupiravir pill, available only by prescription, "as soon as possible after diagnosis of COVID-19 and within five days of symptom onset."

Merck's solution, developed in conjunction with Ridgeback Biotherapeutics, narrowly passed an FDA advisory panel vote in November, with the company reporting that its pill was 30% effective at preventing hospitalization or death from COVID-19. 

The drug isn't authorized for use by those under the age of 18 as it "may affect bone and cartilage growth," the FDA noted. Pregnant women should also avoid the drug, due to potential fetal harm.

Molnupiravir is "not authorized for the pre-exposure or post-exposure prevention of COVID-19" or for treating those hospitalized from COVID-19 because the benefit of the treatment "has not been observed in people when treatment started after hospitalization due to COVID-19."

Pfizer's pill, by contrast, was cleared for use by those aged 12 or older. Pfizer's treatment has three tablets that are taken twice daily for five days (30 pills total), while Merck's approach has four 200-milligram capsules taken every 12 hours for five days (40 pills total). 

"Today's authorization provides an additional treatment option against the COVID-19 virus in the form of a pill that can be taken orally," Dr. Patrizia Cavazzoni, director of the FDA's Center for Drug Evaluation and Research, said in a statement. "As new variants of the virus continue to emerge, it is crucial to expand the country's arsenal of COVID-19 therapies using emergency use authorization, while continuing to generate additional data on their safety and effectiveness." 

Similar to the Pfizer pill, which also received emergency use authorization, or EUA, Merck's drug isn't a substitute for vaccination, the FDA said.

The EUA is different from the FDA's regular approval. It's used to "authorize unapproved medical products or unapproved uses of approved medical products" in an emergency to diagnose, treat or prevent serious or life-threatening diseases. 

In examining the Merck pill, the FDA found that it's reasonable to believe molnupiravir may be effective in treating mild to moderate COVID-19 in certain adults when alternative, authorized COVID-19 treatment options aren't accessible or clinically appropriate.