AstraZeneca has reported that its Evusheld (AZD7442) offered substantial protection against symptomatic Covid-19 for a minimum of six months in the Phase III PROVENT trial in high-risk populations.

A cocktail of two long-acting antibodies, tixagevimab (AZD8895) and cilgavimab (AZD1061), Evusheld is obtained from B-cells donated by people who priorly had Covid-19 infection. 

The antibody combination was discovered by Vanderbilt University Medical Center with the company obtaining a licence for it in June 2020.

The randomised, placebo-controlled, double-blind, multicentre trial analysed the safety and efficacy of a 300mg intramuscular dose of Evusheld versus placebo to prevent symptomatic Covid-19 in people who were not infected at baseline. 

Carried out at 87 sites in the US, UK, France, Belgium and Spain, the pre-exposure prophylaxis (prevention) trial enrolled 5,197 subjects.  

Findings showed that Evusheld lowered symptomatic Covid-19 development risk by 77% in the initial analysis and by 83% in the six-month follow-up assessment, versus placebo. 

Furthermore, no cases of severe Covid-19 or disease-associated deaths were reported in the Evusheld arm through the follow-up period.

According to the further pharmacokinetic results, the concentrations of the antibody cocktail were found to be high in serum for six months following dosing, indicating that a single dose could offer durable protection against Covid-19 lasting a minimum of six months.

Evusheld was found to be well tolerated in the trial without any safety concerns detected at either the initial or six-month assessment. 

AstraZeneca BioPharmaceuticals R&D executive vice-president Mene Pangalos said: “These data add to the growing body of evidence supporting the use of Evusheld to help prevent symptomatic and severe Covid-19, especially for those individuals who can’t respond adequately to vaccination and need additional protection. 

“Evusheld is now available in many countries around the world, and we are progressing filings in pre-exposure prophylaxis, as well as mild-to-moderate treatment.”