Biopharmaceutical company AstraZeneca and BioPharmaceuticals on Wednesday confirmed positive high-level results from the primary analysis of Phase III trial of AZD1222 in the US, with the vaccine efficacy consistent with pre-specified interim analysis and the results have been presented to the independent Data Safety Monitoring Board for regulatory submission for US FDA's EUA.

This US Phase III trial (D8110C00001) was led by AstraZeneca and funded by the Biomedical Advanced Research and Development Authority (BARDA) and the National Institute of Allergy and Infectious Diseases (NIAID).

D8110C00001 is a randomized, double-blind, placebo-controlled multicentre Phase III trial assessing the safety, efficacy, and immunogenicity of AZD1222 compared to placebo for the prevention of COVID-19 in 32,449 participants across the US, Peru and Chile.

The companies added that the primary endpoint, vaccine efficacy at preventing symptomatic COVID-19 was 76% occurring 15 days or more after receiving two doses given four weeks apart. The results were comparable across age groups, with vaccine efficacy of 85% in adults 65 years and older. A key secondary endpoint, preventing severe or critical disease and hospitalization, demonstrated 100% efficacy.

AZD1222 was co-invented by the University of Oxford and Vaccitech. It uses a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. The surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus.