Evusheld May Have Less Efficacy Against Omicron Subvariants

AstraZeneca’s COVID-19 antibody Evusheld (tixagevimab/cilgavimab) may have limited efficacy against the Omicron subvariants, BA.1 and BA.1.1, the FDA said.

The agency also amended the therapy’s Emergency Use Authorization (EUA) to double the initial dosage to 300 mg of tixagevimab and 300 mg of cilgavimab, given the concerns over diminished efficacy.

The FDA granted Evusheld emergency authorization in December for treating immunocompromised people 12 years and older who may be unable to mount a proper immune response to a COVID-19 vaccine as well as those who can’t be given a COVID-19 vaccine.

The duration of protection provided by Evusheld against symptomatic SARS-CoV-2 infection may not be as long as was shown in the clinical trial supporting the initial authorization because the clinical trial data came from a time period before the emergence of the BA.1 and BA.1.1 subvariants, the FDA said.