AstraZeneca released efficacy data for its COVID-19 vaccine following notification by an independent monitoring data and safety monitoring committee (DSMB) of possible concerns over outdated trial data. In a separate matter, the company issued a statement regarding vaccine production from Italy.

The DSMB notified the National Institute of Allergy (NIAID) and Infectious Diseases, the Biomedical Advanced Research and Development Authority, and AstraZeneca that it was concerned by information released by AstraZeneca on initial data from its COVID-19 vaccine clinical trial.

“The DSMB expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data.” NIAID reported in a March 24, 2021 statement, “We urge the company to work with the DSMB to review the efficacy data and ensure the most accurate, up-to-date efficacy data be made public as quickly as possible.”

AstraZeneca issued updated efficacy results this week (March 25, 2021). The results showed 76% vaccine efficacy against symptomatic COVID-19, 100% efficacy against severe or critical disease and hospitalization, and 85% efficacy against symptomatic COVID-19 in participants aged 65 years and over.

“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,” said Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D, AstraZeneca, in a March 25, 2021 statement. “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.”

In addition, the DSMB conducted a review of thrombotic events (blood clots) and cerebral venous sinus thrombosis among participants and found no increased risk of these conditions. The primary analysis is pre-specified in the trial protocol and will be the basis for a regulatory submission for emergency use authorization to the US Food and Drug Administration in the coming weeks (as reported on March 25, 2021).

Manufacturing in Italy

In a separate development, AstraZeneca issued a statement on March 24, 2021 to clarify that it was not stockpiling doses of its COVID-19 vaccine doses from a plant in Anagni, Italy.

“There are no exports currently planned other than to COVAX countries,” said the company in a March 24, 2021 statement. “There are 13 million doses of vaccine waiting for quality control release to be dispatched to COVAX as part of the company’s commitment to supply millions of doses to low-income countries. The vaccine was made outside the European Union (EU) and brought to the Anagni plant to be filled into vials. The EU fully supports supplying low-and middle-income countries through the COVAX facility.”

AstraZeneca reported that there are another 16 million doses waiting for quality-control release to be dispatched to Europe. Approximately 10 million doses will be delivered to EU countries during the last week of March (March 2021), and the balance is to be delivered in April (April 2021) as the doses are approved for release after quality control.

“It is incorrect to describe this as a stockpile.” AstraZeneca said in the March 25, 2021 statement. “The process of manufacturing vaccines is very complex and time consuming. In particular, vaccine doses must wait for quality control clearance after the filling of vials is completed.”

Source: National Institute of Allergy and Infectious Diseases (DSMB report), National Institute of Allergy and Infectious Diseases (trial results), AstraZeneca (statement to DSMB), AstraZeneca (trial results), and AstraZeneca (Italy)