Evusheld Significantly Protects Against Symptomatic COVID-19 for at Least 6 Months in High-Risk Populations

Evusheld concentrations remained elevated in serum for 6 months after administration, supporting that a single dose could provide long-term protection against COVID-19.

New data from the phase 3 PROVENT trial of high-risk populations has found that the combination of tixagevimab and cilgavimab (Evusheld) significantly protected against symptomatic COVID-19 for at least 6 months.

According to the study, Evusheld reduced the risk of developing symptomatic COVID-19 by 77% in the primary analysis and by 83% in the 6-month follow-up analysis, compared to placebo. Researchers found no cases of severe disease or COVID-19 related deaths in the Evusheld treatment arm through the 6-month follow-up.

Notably, more than 75% of the study participants at baseline had comorbidities that put them at high risk for severe COVID-19 if they were to become infected, including individuals who are immunocompromised and may have an inadequate response to vaccination. Approximately 2% of the global population is considered at increased risk of an inadequate response to COVID-19 vaccination and may particularly benefit from pre-exposure prophylaxis with Evusheld, according to a press release.

Pharmacokinetic data showed that Evusheld concentrations remained elevated in serum for 6 months after administration, supporting that a single dose could provide long-term protection against COVID-19.

“While COVID-19 vaccines have been highly effective at reducing hospitalization and death, cases continue to surge and many individuals remain at high risk, including immunocompromised individuals and those who cannot be vaccinated,” said principal investigator Myron J. Levin, MD, in the press release. “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.”

In the primary efficacy analysis, a single 300 mg intramuscular dose of Evusheld reduced the risk of developing symptomatic COVID-19 compared to placebo by 77% at a median follow up of 83 days. Symptomatic COVID-19 occurred in 0.2% and 1% of participants in the Evusheld and placebo groups, respectively.

Compared to the primary analysis, the extended follow-up analysis demonstrated a greater reduction in COVID-19 incidence in the Evusheld group, with an 83% relative risk reduction with Evusheld compared to placebo at a median follow up of 196 days. Symptomatic COVID-19 occurred in 0.3% and 1.8% of participants in the Evusheld and placebo groups, respectively. Efficacy was generally consistent across participant subgroups, where evaluable.

Importantly, there were no cases of severe or critical COVID-19, COVID-19-related deaths, or hospitalizations in the Evusheld group by the 6-month follow-up analysis. There were 5 cases of severe or critical disease, 7 hospitalizations, and 2 COVID-19-related deaths in the placebo groups.

Evusheld was generally well-tolerated and no safety issues were identified at either the primary or 6-month analysis. Adverse events (AEs) accrued at similar rates in both the Evusheld and placebo groups. The most common AE was injection-site reaction, occurring in 2.4% of participants in the Evusheld group and 2.1% of participants in the placebo group.

“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,” said Mene Pangalos, PhD, executive vice president of biopharmaceuticals research and development at AstraZeneca, in the press release. “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.”

REFERENCE

Evusheld significantly protected against symptomatic COVID-19 for at least 6 months in PROVENT phase III trial in high-risk populations. News release. AstraZeneca; April 20, 2022. Accessed April 25, 2022. https://www.astrazeneca.com/media-centre/press-releases/2022/evusheld-significantly-protected-against-symptomatic-covid-19-for-at-least-six-months-in-provent-phase-iii-trial-in-high-risk-populations1.html