Long read - update on the Oxford / AZ vaccine
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AstraZeneca has a good chance of delivering late-phase data on its COVID-19 vaccine this year, the chief investigator of the Oxford Vaccine Trial said. The timing gives AstraZeneca a “small chance” of being able to start distributing the AZD1222 vaccine in the U.K. before Christmas.
Andrew Pollard, M.D., Ph.D., made the comments at a
meeting of a U.K. parliamentary committee in his capacity as chief investigator of global AZD1222 clinical trials sponsored by the University of Oxford. While AstraZeneca is the sponsor of late-phase AZD1222 trials in the U.S. and Russia, Oxford, the originator of the vaccine, is taking the lead on phase 3 studies in Brazil and the U.K.
Pollard’s prominent position in the COVID-19 vaccine race led politicians on the U.K.’s Science and Technology Committee to call him to give evidence on Wednesday. Asked about when AZD1222 will be available, Pollard explained that the first step is to reach the point at which data are ready for analysis.
“I'm optimistic that we could reach that point before the end of this year,” Pollard said.
If the data are positive, the vaccine will need to undergo regulatory review and then be deployed to the groups identified as the first recipients in a long queue. Pollard said the timelines for those steps “are not entirely clear to me at the moment.” Efforts to accelerate the steps could be complicated by the near-simultaneous submission of multiple COVID-19 vaccines for approval.
Faced with multiple uncertainties, Pollard said it is “very difficult” to say whether AZD1222 will come to market in the U.K. by Christmas. The Oxford professor sees a “small chance” of that happening.
The timing will depend, in part, on the efficacy of the vaccine. As Pollard explained, efficacy affects the number of COVID-19 cases a study needs to show whether a vaccine works. If the vaccine is only 50% effective, more participants in the trial will need to develop COVID-19 to show it works.
Pollard hopes AZD1222 and other vaccines will be more than 50% effective. That would cut the time it takes for sponsors to show efficacy and mean the vaccines are more impactful when rolled out to populations. Yet, Pollard also said policymakers may need to consider what they will do if vaccines fall short of the 50% effectiveness bar set by the FDA.
“If vaccines only prevented 40% of the cases, would that be useful for the NHS? These are the sorts of decisions that potentially policy makers may need to be thinking through in the months ahead depending on where vaccines land,” Pollard said.
Pollard spoke at the same session as Robin Shattock, the lead for Imperial College London’s COVID-19 vaccine. Imperial is developing a self-amplifying RNA (saRNA) vaccine.
Like mRNA vaccines such as those in development at BioNTech and Moderna, saRNA jabs carry nucleic acids designed to make cells in the body produce an antigen. The difference is saRNA also encodes for proteins that enable RNA vaccine replication, potentially enabling them to provide protection at lower doses than is possible with mRNA.
Working with a novel platform, Imperial trailed Oxford into the clinic and remains behind. Shattock said his team could generate an efficacy signal midway through 2021 “with the right level of support.” The U.K. government has helped Imperial reach this point. Shattock made the case for further support at the committee meeting.
“One of the advantages of the technology that we're developing is that it can be used for repeated boosting immunizations, either to boost existing vaccines or to boost itself. So, if immunity wanes we would be well positioned with this technology to provide boosting strategies for the U.K.,” Shattock said.
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