AstraZeneca’s Evusheld (tixagevimab co-packaged with cilgavimab), a long-acting antibody combination for the prevention of Covid-19, retains neutralisation activity against the Omicron SARS-CoV-2 variant, according to new authentic ‘live’ virus neutralisation data from both University College Oxford, UK and Washington University School of Medicine, St. Louis, US.

The findings were posted online on bioRxiv, a preprint server.

Evusheld’s Inhibitory Concentration 50 (IC50), a measure of neutralising potency of an antibody, was 273 ng/ml and 147 ng/ml in the Oxford and Washington University studies, respectively. The levels are within the range of neutralising antibody titres found in individuals who have been previously infected with and recovered naturally from COVID-19.

The data were generated from laboratory testing using actual live virus isolated from individuals who contracted the Omicron variant of Covid-19, considered a ‘gold standard’ for antibody neutralisation studies. Evusheld is one of only two antibody therapies authorised for use that showed neutralising activity against Omicron and against all other variants of concern in these two studies.

These findings are in line with pseudovirus neutralising data from independent investigators at the US Food and Drug Administration (FDA) announced on December 16^th 2021 and add to the growing body of preclinical evidence demonstrating that Evusheld retains activity against all tested SARS-CoV-2 variants of concern to date.

By combining two particularly potent antibodies with different and complementary activities against the virus, Evusheld was designed to evade potential resistance with the emergence of new SARS-CoV-2 variants.