An unusually public spat between AstraZeneca and the US National Institute of Allergy and Infectious Diseases (NIAID) earlier this week saw the NIAID question the efficacy figures released by AstraZeneca on Monday (the NIAID raised concerns that AstraZeneca ‘may have included outdated information’) in its interim analysis trial data.
This morning, however, AstraZeneca has released its primary analysis, saying it supports the earlier data. This primary analysis will be the basis for a regulatory submission for Emergency Use Authorization (EUA) to the US FDA ‘in the coming weeks’.
Primary analysis: the data
The primary efficacy analysis included the accrual of 190 symptomatic cases of COVID-19 from the 32,449 trial participants in the US Phase 3 trial (adding 49 cases to the interim analysis announced on Monday).
The primary endpoint, vaccine efficacy at preventing symptomatic COVID-19 was 76% (confidence interval: 68% to 82%) occurring 15 days or more after receiving two doses given four weeks apart (the interim analysis had put the overall efficacy figure at 79%).
Results were comparable across age groups, with vaccine efficacy of 85% (CI: 58% to 95%) in adults 65+ (the interim analysis had put the efficacy figure for ages 65+ at 80%).
A key secondary endpoint, preventing severe or critical disease and hospitalisation, demonstrated 100% efficacy (as in the interim analysis).
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.
Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D at AstraZeneca, said: “The primary analysis is consistent with our previously released interim analysis, and confirms that our COVID-19 vaccine is highly effective in adults, including those aged 65 years and over.
"We look forward to filing our regulatory submission for Emergency Use Authorization in the US and preparing for the rollout of millions of doses across America.”
AstraZeneca will also submit the primary analysis for peer-reviewed publication in the coming weeks.