The FDA has warned that the investigational long-acting monoclonal antibodies tixagevimab and cilgavimab (Evusheld – AstraZeneca) are unlikely to neutralize the XBB.1.5 Omicron variant of SARS-CoV-2.1 Evusheld is available under an Emergency Use Authorization (EUA) for IM pre-exposure prophylaxis of COVID-19 in persons ≥12 years old who weigh ≥40 kg and have either a history of a severe adverse reaction that prevents their vaccination against COVID-19 or moderate or severe immune compromise.2,3
According to the FDA, because tixagevimab and cilgavimab do not neutralize the XBB Omicron variant of SARS-CoV-2, they are unlikely to neutralize the closely related XBB.1.5 variant.1 The CDC has estimated that the XBB.1.5 variant caused 43% of COVID-19 cases in the week ending January 14, 2023, up from 7% of cases 4 weeks earlier.4
- FDA. Drug safety and availability. FDA releases important information about risk of COVID-19 due to certain variants not neutralized by Evusheld. January 6, 2023. Available at: https://bit.ly/3W4lYBZ. Accessed January 13, 2023.
- Tixagevimab and cilgavimab (Evusheld) for pre-exposure prophylaxis of COVID-19. Med Lett Drugs Ther 2022; 64:1.
- COVID-19 update: Dosing interval for tixagevimab/cilgavimab (Evusheld). Med Lett Drugs Ther 2022; 64:e122.
- CDC. COVID data tracker. Variant proportions. January 14, 2023. Available at: https://bit.ly/3Ka3HhH. Accessed January 13, 2023.