AstraZeneca Looks to Clear Confusion Over Vaccine Results with Additional Studies

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As concerns continue to grow over the efficacy of AstraZeneca’s experimental COVID-19 vaccine, the pharma giant could be heading toward conducting additional studies. Another clinical study could confirm the 90% efficacy data that stemmed from accidental use of a half-dose in an arm of its Phase III trial.

Prior to the Thanksgiving holiday in the United States, AstraZeneca announced data from its Phase III study that showed up to 90% efficacy for its vaccine. But, the results are confusing. As BioSpace reported, one dosing regimen was given at a half dose and demonstrated 90% efficacy, followed by a full dose at least one month apart. Another dosing regimen demonstrated 62% efficacy when given two full doses at least one month apart. The combined analysis showed average efficacy of 70%.

Because of the disparity in the results, AstraZeneca is on course to conduct another trial. Chief Executive Officer Pascal Soriot told Bloomberg the additional study will validate the 90% efficacy from the half-dose regimen. Soriot told the news organization that the additional study will likely be international, but noted “this one could be faster because we know the efficacy is high so we need a smaller number of patients.”

The disparity in the initial global study could delay potential authorization of the vaccine in the United States. Soriot said he didn’t expect the additional trial to hold up regulatory approvals in the U.K. and European Union.

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