March 23, 2021 -- Late in the day on March 22, the data safety monitoring board (DSMB) notified the National Institute of Allergy and Infectious Diseases, the Biomedical Advanced Research and Development Authority, and AstraZeneca that it was concerned about information released by AstraZeneca that may result in an incomplete view of efficacy data. In response, AstraZeneca released a statement expressing the company's intention to work with the DSMB and release results of the primary analysis within 48 hours.
According to the DSMB, the information released by AstraZeneca in its interim analysis of its phase III clinical trial data on March 22 may have included outdated information that may have an effect on the reported efficacy. The board urged the company to review its efficacy data and "ensure the most accurate, up-to-date efficacy data be made public as quickly as possible."
In addition to the DSMB review, the AstraZeneca vaccine will only be considered for authorization after thorough review of the data by independent advisory committees of the U.S. Food and Drug Administration (FDA) and the U.S. Centers for Disease Control and Prevention (CDC).
AstraZeneca said that the data they released on March 22 were based on a prespecified interim analysis with a data cutoff of February 17. An internal review of the preliminary assessment of the primary analysis found that the results were consistent with the interim analysis. However, the company is completing additional validation of the statistical analysis to address the DSMB's concerns.
The company also stated that it is immediately engaging with the DSMB to share analysis with the most up-to-date efficacy data. They intend to make the results of the primary analysis public within 48 hours.