The FDA limits the use of some monoclonal antibodies treatments

As COVID-19 continues to surge in places across the county, the Food and Drug Administration is curbing the use of two out of three monoclonal antibody treatments available in the U.S. because data shows they aren't effective against the omicron variant, the agency announced Monday.

The two drugs, made by Regeneron and by Eli Lilly, worked well earlier in the pandemic with non-omicron variants, NPR's Pien Huang told Morning Edition. But data shows they aren't effective against omicron, which accounts for an estimated 99% of U.S. COVID-19 cases.

The drugs are bamlanivimab and etesevimab (which are administered together) and REGEN-COV (casirivimab and imdevimab); the FDA has limited their use to patients infected with a variant that is susceptible to these treatments.

"Honestly, I'm shocked that it took them this long to do it because things are bad enough without wasting valuable health care provider time infusing a medicine that is not going to be effective," Erin Fox, a pharmacy director at University of Utah Health, told NPR.

The makers of the drugs acknowledge the medications don't work well against omicron, notes Huang. But some officials aren't on board. Florida Gov. Ron DeSantis, who has been an outspoken supporter of monoclonal antibody treatments in Florida, criticized the FDA's move to restrict authorization.

Vaccines and early treatments developed for lessening COVID-19's severity are critical to the U.S.'s response to the ongoing pandemic.

Monoclonal antibody treatments work by infusing COVID-19 patients with laboratory-made proteins that mimic the immune system's processes for fighting off pathogens; they're one type of early treatment that can make COVID-19 less severe.

The FDA reports the monoclonal antibody treatment sotrovimab is still authorized because it is expected to remain effective at lessening the risk of severe disease even against the omicron variant; although it is in short supply across the country. Other therapies are also available including Paxlovid and molnupiravir, two pills patients can take at home to reduce the risk of hospitalization from severe COVID-19, and the antiviral drug remdesivir, for which the FDA recently broadened approval.

The Department of Health and Human Services will no longer distribute the monoclonal antibody treatments for which the FDA has reduced its authorization. The department says that in the future, if people are likely to be infected with a variant that is susceptible to these treatments, use of the drugs may be authorized again.

This story originally appeared on the Morning Edition live blog.

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