Evusheld (tixagevimab co-packaged with cilgavimab) significantly reduced the risk of developing symptomatic COVID-19 for at least 6 months, according to phase 3 trial data.

Evusheld is a combination of 2 long-acting monoclonal antibodies designed to bind to distinct sites on the SARS-CoV-2 spike protein. The double-blind, placebo-controlled PROVENT trial (ClinicalTrials.gov Identifier: NCT04625725) evaluated the efficacy and safety of Evusheld for the prevention of COVID-19 in adults. Patients were randomly assigned 2:1 to receive a single 300mg dose of Evusheld or placebo. 

In the primary analysis, treatment with Evusheld reduced the risk of developing symptomatic COVID-19 by 77% at a median follow-up of 83 days compared with placebo (95% CI, 46-90; P <.001). Symptomatic COVID-19 occurred in 0.2% (n=8/3441) of patients in the Evusheld arm and 1.0% (n=17/1731) of patients in the placebo arm.

At the 6-month follow-up, a lower incidence of COVID-19 was observed in the Evusheld group vs the placebo group, with a relative risk reduction of 83% (95% CI, 66-91). Symptomatic COVID-19 occurred in 0.3% (n=11/3441) of patients in the Evusheld arm and 1.8% (n=31/1731) of patients in the placebo arm. Efficacy was generally consistent across patient subgroups, where evaluable.

Additionally, there were no cases of severe or critical COVID-19, COVID-19-related deaths or hospitalizations in the Evusheld arm at the 6-month follow-up analysis. In the placebo arm, there were 5 cases of severe or critical COVID-19, 7 cases of COVID-19-related hospitalizations, and 2 cases of COVID-19-related deaths.

As for safety, Evusheld was generally well tolerated with no safety issues identified. The most common adverse reaction was injection-site reaction. Pharmacokinetic data showed that Evusheld concentrations remained elevated in serum for 6 months following administration.

Myron J. Levin, MD, Professor of Pediatrics and Medicine, University of Colorado School of Medicine, US, and PROVENT principal investigator, said: “[…] These important data now published in the New England Journal of Medicine provide confidence that one easily administered intramuscular dose of Evusheld could provide vulnerable populations long-lasting protection. In addition, Evusheld has been shown to neutralize BA.2, currently the dominant circulating COVID-19 variant.”

Evusheld is currently authorized under emergency use for the preexposure prophylaxis of COVID-19 in adults and pediatric individuals (12 years of age and older weighing at least 40kg) who are not currently infected with SARS-CoV-2 and who have not had a known recent exposure to an individual infected with SARS-CoV-2, and:

  • Who have moderate to severe immune compromise due to a medical condition or receipt of immunosuppressive medications or treatments and may not mount an adequate immune response to COVID-19 vaccination; or
  • For whom vaccination with any available COVID-19 vaccine, according to the approved or authorized schedule, is not recommended due to a history of severe adverse reaction (eg, severe allergic reaction) to a COVID-19 vaccine(s) and/or COVID19 vaccine component(s).


  1. Evusheld™ significantly protected against symptomatic COVID-19 for at least six months in PROVENT phase III trial in high-risk populations. News release. AstraZeneca. Accessed April 21, 2022. https://www.businesswire.com/news/home/20220420006206/en/EVUSHELD%E2%84%A2%C2%A0-significantly-protected-against-symptomatic-COVID-19-for-at-least-six-months-in-PROVENT-Phase-III-trial-in-high-risk-populations
  2. Levin MJ, Ustianowski A, De Wit S, et al. Intramuscular AZD7442 (tixagevimab–cilgavimab) for prevention of COVID-19. N Engl J Med. Published online April 20, 2022. doi:10.1056/NEJMoa2116620