The Food and Drug Administration announced Thursday afternoon that it has revised the Emergency Use Authorization (EUA) for AstraZeneca’s Evusheld, noting that the drug is not authorized for use in the U.S. until further notice.

Due to the ongoing evolution of COVID-19 subvariants, the FDA said that Evusheld is “unlikely to be active” against certain strains of the virus.

The FDA said hospitals, health systems and healthcare providers should retain all existing supplies of Evusheld in the event that future subvariants are found to be neutralized by the treatment. Still, the FDA noted that new variants of COVID-19 that aren’t neutralized by Evusheld account for 90% of current domestic infections.  

“Today’s action to limit the use of Evusheld prevents exposing patients to possible side effects of Evusheld such as allergic reactions, which can be potentially serious, at a time when fewer than 10% of circulating variants in the U.S. causing infection are susceptible to the product,” the agency said in a press release. 

Evusheld received an EUA from the FDA in December 2021 as the U.S. dealt with the wave of infections caused by the Omicron variant of COVID-19.

AstraZeneca said it will continue to work with the FDA and other health authorities to “collect, assess and share relevant data” regarding its monoclonal antibody therapy and COVID-19 variants. The British pharma giant noted that Evusheld remains authorized for pre-exposure prophylaxis of COVID-19 in the EU and Japan. 

The FDA decision comes more than six months after AstraZeneca launched its first direct-to-consumer ad campaign for Evusheld, which aired on TV networks as well as online platforms.

Andrew Leone, executive director of vaccine sales and marketing at AstraZeneca, told MM+M last year that rolling out an ad campaign for the emergency use product was borne out of lower utilization of the drug than expected.

“There are still millions of immunocompromised individuals who could benefit from an intervention like Evusheld,” Leone said. 

Still, the EUA revocation for Evusheld will likely sting for AstraZeneca. The treatment generated $1.4 billion in product sales during Q3 2022, according to the company’s latest earnings report released in November.