Federal health authorities say Merck’s experimental COVID-19 pill is effective against the virus, but they will seek outside expert opinion on the risks of birth defects and other potential problems during pregnancy.
The FDA has released its analysis of the tablet ahead of a public meeting next week where scientists and other experts will discuss its safety and effectiveness. The agency is not required to follow the advice of the group.
The FDA scientists said their review highlighted several potential risks, including possible toxicity and birth defects. Given these risks, the FDA will ask its advisers if the drug should never be given during pregnancy or if it can be made available in certain cases.
Under this scenario, the FDA said the drug would contain warnings about risks during pregnancy, but doctors would still be able to prescribe it in certain cases where its benefits might outweigh the risks to patients.
The FDA said that given the safety concerns, Merck agreed that the drug will not be used in children.
In addition, the FDA has expressed concern that the Merck drug has led to small changes in the signature protein of the coronavirus, which it uses to enter human cells. In theory, the FDA warns, these changes could lead to new dangerous options.
Regulators also noted that Merck has collected far less overall safety data for its drug than has been collected for other COVID-19 treatments.
The FDA will ask its independent consultants to discuss all of these issues and then vote on whether the overall benefits of the drug outweigh its risks.
All COVID-19 drugs currently approved by the FDA require injection or intravenous administration and can only be administered by healthcare professionals. If permitted, Merck will be the first drug that US patients can take at home to relieve symptoms and speed up recovery. It is already licensed for emergency use in the UK.
The meeting marks the first time that a new drug for COVID-19 has been publicly reviewed by regulators, signaling close attention and attention to a pill that could soon be used by millions of Americans.
The drug molnupiravir has been shown to significantly reduce the incidence of hospitalizations and deaths among people with mild to moderate coronavirus infection.
Merck’s drug takes a new approach to combating COVID-19: It inserts tiny mutations into the genetic code of the coronavirus to the point where it cannot reproduce.
But this genetic effect has raised concerns that, in rare cases, the drug could cause birth defects or tumors.
Pregnant women were excluded from the Merck study. Both the women and men in the study were instructed to use contraception or abstain from sex.
For its part, Merck says the results of the company’s two rodent studies show that “molnupiravir does not cause mutations or DNA damage in these animal models.” The company said the rodents received higher doses for longer periods of time than people who took the drug.
FDA reviewers also confirmed Merck’s previously reported interim results that the pill reduced hospital admissions and deaths by about half among patients with early symptoms of COVID-19 who were at increased risk due to health problems.
However, on Friday morning, Merck announced updated results for the same study that showed less benefit from the drug.
Among more than 1,400 adults who participated in the company’s study, molnupiravir reduced the cumulative risk of hospitalization and death by 30%, less than 50% initially reported based on incomplete results.
About 7% of patients who received Merck’s drug within five days of the onset of COVID-19 symptoms were hospitalized and one died. This is compared with 10% of hospitalized patients who took placebo and nine deaths.