GSK, Vir's COVID antibody put on ice as BA.2 subvariant takes hold

Throughout the COVID-19 pandemic, emerging variants have prompted regulators to force antibody products off the market if testing showed that they were no longer effective against the disease. Now, GlaxoSmithKline and Vir Biotechnology are the latest victims as the FDA has revoked their emergency authorization for sotrovimab, also known as Xevudy.

Citing the prevalence of omicron's BA.2 subvariant in the U.S., the agency said Tuesday that Xevudy is "no longer authorized to treat COVID-19 in any U.S. region." Officials had previously halted its use in a handful of Northeast states and then later expanded the restrictions to about half of the country.

Data on the antibody drug show its authorized dose is "unlikely to be effective against" BA.2, according to the FDA. Since BA.2 cases now represent more than half of all U.S. infections, the agency is cracking down on the treatment's use—for now. 

Officials will "continue to monitor BA.2 in all U.S. regions and will provide follow-up communication when appropriate," the agency said.

GSK and Vir aren't alone in hitting variant setbacks. The previously popular antibody drugs from Eli Lilly and Regeneron are currently shelved thanks to omicron, FDA records show, though a newer Eli Lilly antibody called bebtelovimab is authorized in all regions.

Meanwhile, antivirals from Merck and Pfizer continue to make their way to patients, and AstraZeneca's Evusheld carries an FDA nod for preexposure prophylaxis in people who have weakened immune systems or who cannot take COVID-19 vaccines.

For GSK and Vir, the FDA halt could mean a sales hit. Xevudy revenues hit 958 million pounds sterling ($1.26 billion U.S.) in 2021, with 89% of the figure coming in last year's fourth quarter. As for 2022, GSK expects to generate 1.4 billion pounds ($1.83 billion) from the treatment.