'Positive news' on AstraZeneca's COVID-19 vaccine is imminent: report

AstraZeneca and the University of Oxford are set to share “positive news” on their COVID-19 vaccine soon, according to a leading U.K. journalist. The update, which could come as soon as tomorrow, may shed light on how the front-runner vaccine fared in early clinical trials. 

AZD1222, an recombinant adenovirus vaccine candidate that originated in Oxford, moved into phase 2/3 in May on the strength of data from a 1,000-subject phase 1 trial. However, the researchers are yet to share clinical data from the phase 1, leaving observers to argue over the results of a study conducted in monkeys to determine whether the vaccine is likely to work.

Now, Robert Peston, a prominent journalist at British broadcaster ITV, has said there will soon be positive news from trials of AZD1222. The Lancet is due to publish clinical data on the vaccine. 

Peston said “the vaccine is generating the kind of antibody and T-cell response that the researchers would hope to see.” That is all we have to go on at this stage, but the focus on T-cell response—in the Peston quote and other sources linked to the program—suggests the researchers may perceive that as a strength of the data or a bright spot amid underwhelming antibody results.

Antibodies are relatively simple to measure and serve as a surrogate for T-cell response. However, a growing body of evidence shows antibody-negative individuals can have a T-cell response. The relative importance of antibody and T-cell responses is unclear, as is the level needed to achieve immunity, but it appears both elements play some role.

A former Harvard Medical School professor savaged preclinical AZD1222 results, in part due to data on the levels of neutralizing antibodies. With their first clinical data drop looming, people involved with AZD1222 are talking up the importance of T cells.  

“An important point to keep in mind is that there are two dimensions to the immune response: antibodies and T-cells. Everybody is focused on antibodies but there is a growing body of evidence suggesting that the T-cells response is important in the defence against coronavirus,” a source told Peston. The comment echoes those made by people linked to AZD1222, including AstraZeneca Executive Vice President Mene Pangalos, in a feature published in Bloomberg.

Data published by Moderna this week show the preferred dose of its COVID-19 vaccine elicited CD4 T-cell responses. Investigators also detected low level CD8 T-cell responses after the second shot at its preferred dose. BioNTech and Pfizer focused on antibodies in their COVID-19 vaccine data drop.