FDA says Merck COVID-19 pill is effective, experts will now review safety concerns

The Food and Drug Administration has determined that molnupiravir, an experimental COVID-19 pill from pharmaceutical giant Merck, is effective against the virus, and the agency will now seek expert input on outstanding safety questions, including the potential for birth defects and other problems if the pill is taken during pregnancy.

The FDA will convene publicly next week during a conference where academics and other experts will discuss the safety and efficacy of the drug.

The federal agency says its scientists have identified several potential risks from the drug, including toxicity and birth defects. Regulators will ask experts whether there should be a blanket prohibition on the pill during pregnancy, or if there are case exceptions. Pregnant women were excluded from Merck's study. The FDA is not required to follow the group's guidance.

The agency has identified a concern that the Merck pill can lead to small changes in the coronavirus' signature spike protein, which could potentially lead to dangerous new variants of the virus. Regulators noted that significantly less safety data was accumulated overall for the Merck pill than for virtually all other COVID-19 therapeutics.

The conference of independent advisers will weigh all of these concerns before voting on whether the pill's benefits outweigh its risks. According to Merck's most recent study, the drug reduced the combined risk of hospitalization and death due to the virus by 30% — less than the 50% initially reported by the company based on incomplete studies.