The US Food and Drug Administration (FDA) on Monday revoked the emergency use authorisation it had issued earlier for monoclonal antibody treatments for COVID-19 made by Regeneron and Eli Lilly.

Announcing its decision, the FDA said that monoclonal antibody treatments are “highly unlikely to be active against the omicron variant,” which according to the Centers for Disease Control and Prevention (CDC) accounts for 99% of the COVID-19 cases in the US.

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“These treatments are not authorized for use in any U.S. states, territories, and jurisdictions at this time,” the FDA added, emphasizing that such treatments have been banned for the time being.

The announcement caught several monoclonal antibody treatment sites off guard, including Florida. In response to the announcement, the Florida Health Department said that the FDA had provided no prior notice of revoking authorisation for the treatment, adding that the FDA had also failed to provide clinical evidence for legally blocking the use of the treatment.

Florida Governor Ron DeSantis, who aggressively promoted monoclonal antibody treatments as part of his administration’s COVID-19 response, also criticised the FDA, saying, “This indefensible edict takes treatment out of the hands of medical professionals and will cost some Americans their lives.”

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However, the FDA did not rule out re-authorising monoclonal antibody treatments in future, saying, “In the future, if patients in certain geographic regions are likely to be infected or exposed to a variant that is susceptible to these treatments, then use of these treatments may be authorized in these regions.”

Although monoclonal antibody treatments have been barred from use for the time being, other drugs such as Paxlovid, sotrovimab, Veklury (remdesivir), and molnupiravir are still expected to be effective against the the highly transmissible omicron variant of the coronavirus.