AstraZeneca is likely to conduct a further global trial to assess the efficacy of its COVID-19
vaccine, its chief executive, Pascal Soriot, said Thursday after questions about the results of its late-stage study.
Rather than adding the trial arm to an ongoing process in the US, a new study would be conducted to evaluate a lower dose that worked better than a full amount in the AstraZeneca studies, Soriot said in a Bloomberg report. News.
“Now that we’ve found what looks like better efficacy, we have to validate this, so we need to do an additional study,” Soriot said.
Soriot said it would probably be another “international study, but this one could be faster because we know the efficacy is high, so we need fewer patients.”
The news comes as AstraZeneca is faced with questions about its success rate that some experts say could hamper its chances of gaining speedy regulatory approval from the US and the EU.
Several scientists have raised questions about the robustness of results published Monday showing the experimental vaccine was 90% effective in a subset of trial participants who initially mistakenly received a half dose followed by a full dose.
Soriot said he did not expect the additional trial to delay regulatory approvals from the UK and Europe.
However, approval by the U.S. Food and Drug Administration (FDA) may take longer because the agency is unlikely to approve the vaccine based on studies done elsewhere, especially given questions about the results, he said.
Authorization is still awaited in some countries before the end of the year, he added.
AstraZeneca’s head of research, Mene Pangalos, told Reuters on Monday that researchers had stumbled upon the half-dose regimen by accident, saying that a subset of the trial was given a smaller starting dose by mistake.
It had previously said that the company would initiate discussions with the FDA to change the design of its COVID-19 trial of the vaccine to add the most effective dosing regimen.
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