The Food and Drug Administration’s decision to effectively revoke emergency use authorization for two monoclonal antibody treatments has left experts divided, with some calling it the right move and others asserting it shouldn’t have been done.

The agency, of the FDA, on Jan. 24 announced it was barring use of treatments from Eli Lilly and Regeneron anywhere in the country because of federal data that indicate the Omicron virus variant is behind the vast majority of COVID-19 cases.

The regulator cited “the most recent information and data available” but did not link to any studies or real-world evidence. Instead, the agency pointed to how a National Institutes of Health (NIH) advisory panel recently recommended against administration of the drugs. The panel used a non-peer-reviewed paper and an unedited manuscript to support its advice.

The regulator also relied on internal experiments, which found they did not perform well against Omicron, according to updated fact sheets for health care providers.