FDA Pulls Authorization for Evusheld, Says It’s Ineffective Against New COVID Mutations

Packaging and vials for AstraZeneca's Evusheld antibody COVID-19 medication. AstraZeneca via AP

Evusheld has become the latest COVID-19 antibody drug to lose federal authorization after it was deemed ineffective against the dominant versions of the virus.

The U.S. Food and Drug Administration (FDA) on Thursday withdrew its emergency use authorization for Evusheld, a two-dose cocktail of monoclonal antibodies meant to provide protection to those who have a compromised immune system that makes them more vulnerable to severe COVID-19 infection than others.

Monoclonal antibodies are laboratory-made proteins that mimic the immune system’s ability to fight off harmful pathogens such as viruses, the FDA explained in the announcement of the changes. This means that as viruses mutate over time, antibody treatments may be rendered useless by the mutations the virus has picked up.

The decision is not surprising, as the FDA warned health care professionals and patients in October 2022 about the “increased risk” of Evusheld not being able to neutralize emerging new COVID variants. Earlier this month, the agency made it clear that it wasn’t expecting Evusheld to be effective against the XBB.1.5 subvariant, which at that time was estimated to account for nearly 30 percent of circulating variants across the nation.

With that said, the FDA nonetheless has decided to wait for additional data to verify their concerns. Citing the data from the U.S. Centers for Disease Control and Prevention (CDC), the FDA indicated that Evusheld is indeed not active against XBB.1.5, which is now responsible for about half of all new COVID cases nationwide.

Specifically, the FDA reported (pdf) that Evusheld doesn’t neutralize Omicron subvariants BQ.1, BQ.1.1, BF.7, BF.11, BA.5.2.6, BA.4.6, BA.2.75.2, XBB and XBB.1.5.1. These variants collectively account for 90 percent of all U.S. infections.

The move to limit the use of Evusheld also has to do with the medication’s side effects, such as allergic reactions, which can be potentially serious, according to the FDA.

AstraZeneca, the British-Swedish pharmaceutical giant that developed the drug, declared that it has started trials of another antibody, called LAAB, which so far has been able to neutralize all variants in lab settings.

“AstraZeneca is aiming to make the new LAAB available in the second half of 2023, subject to trial readouts and regulatory reviews,” the company said in a statement after the FDA pulled Evusheld authorization.

Evusheld currently remains authorized in many other countries, including Japan and those of the European Union, the company noted.

With Evusheld knocked out, there is no FDA-authorized monoclonal antibody left for immune-compromised patients who wanted a pre-exposure treatment. The last of its kind, Bebtelovimab developed by AbCellera and Eli Lilly, lost its emergency use authorization in November 2022.