On Jan. 26, the FDA revoked its emergency use authorization for Evusheld, a monoclonal antibody authorized to treat COVID-19, after finding it's ineffective against about 90 percent of circulating variants.
It was the only FDA-authorized preexposure prophylaxis COVID-19 treatment in the U.S., meaning those who cannot take the vaccine because of contraindications now lack a prevention drug.
"Evusheld is not currently authorized for use in the U.S. until further notice by the Agency," the FDA said in a statement. "Data show Evusheld is unlikely to be active against certain SARS-CoV-2 variants. According to the most recent CDC Nowcast data, these variants are projected to be responsible for more than 90 percent of current infections in the U.S."
The FDA has hinted for months at the revoked authorization of AstraZeneca's Evusheld (tixagevimab and cilgavimab). In October, it said it may lose efficacy; in November, it said it wouldn't be effective against subvariant BQ.1; in January, it said it's likely resistant to subvariant XBB.1.5.
It is ineffective against these subvariants, according to CDC data:
- XBB.1.5 (49.1 percent of cases)
- BQ.1.1 (26.9 percent)
- BQ.1 (13.3 percent)
- XBB (3.3 percent)
- BF.7 (1 percent)
- BA.5.2.6 (0.4 percent)
- BF.11 (0.2 percent)
- BA.4.6 (0.1 percent)
- BA.2.75.2 (0 percent)
The FDA told AstraZeneca that "if the national prevalence of resistant variants decreases to 90 percent or less on a sustained basis," the authorization may return, the drugmaker said in a Jan. 26 news release.
Monoclonal antibodies are hyper-specific designs, John Grabenstein, PhD, scientific communications director for immunize.org and former global executive director for medical affairs in Merck's vaccine division, told Becker's after the FDA pulled its EUA for Eli Lilly's COVID-19 drug.
"The lock has changed, and that key has no longer worked," Dr. Grabenstein said of bebtelovimab, Eli Lilly's monoclonal antibody drug. "The virus changed shape in a way that made the antibody product not relevant, not able to work anymore."