AZD 1222 US Phase III primary analysis confirms safety and efficacy for prevention of COVID-19 – AstraZeneca

Positive high-level results from the primary analysis of the Phase III trial of AZD 1222 in the US have confirmed vaccine efficacy consistent with the pre-specified interim analysis announced on Monday 22 March 2021.

These results have been presented to the independent Data Safety Monitoring Board. The primary analysis is pre-specified in the protocol and will be the basis for a regulatory submission for Emergency Use Authorization to the FDA in the coming weeks.

This primary efficacy analysis included the accrual of 190 symptomatic cases of COVID-19 from the 32,449 trial participants, an additional 49 cases to the previously announced interim analysis. Participants were randomised on a 2:1 ratio between the vaccine and placebo group. The primary endpoint, vaccine efficacy at preventing symptomatic COVID-19 was 76% (confidence interval (CI): 68% to 82%) occurring 15 days or more after receiving two doses given four weeks apart. In addition, results were comparable across age groups, with vaccine efficacy of 85% (CI: 58% to 95%) in adults 65 years and older. A key secondary endpoint, preventing severe or critical disease and hospitalisation, demonstrated 100% efficacy.

There were eight cases of severe COVID-19 observed in the primary analysis with all of those cases in the placebo group. The vaccine was well tolerated, and no safety concerns related to the vaccine were identified.