AstraZeneca CEO Pascal Soriot said on Nov. 26 that the company is likely to run an additional global trial on its COVID-19 vaccine to assess its efficacy at a lower dosage, after questions were raised about the vaccine’s preliminary results.
Soriot’s remarks came after the company on Monday claimed that its vaccine for the CCP (Chinese Communist Party) virus, developed along with Oxford University, could be around 90 percent effective when volunteers were given a half-dose shot, and a full dose a month or more later, but only 62 percent effective when volunteers were given two full doses.
AstraZeneca and Oxford University on Wednesday acknowledged a manufacturing error.
Instead of adding the trial to an ongoing U.S. process, Soriot said that a new test to confirm the 90 percent efficacy rate is likely to happen to diffuse uncertainty surrounding initial results.
“Now that we’ve found what looks like a better efficacy we have to validate this, so we need to do an additional study,” Soriot told Bloomberg Thursday.
The new study will most likely be another “international study, but this one could be faster because we know the efficacy is high so we need a smaller number of patients,” he said.
The news comes as AstraZeneca faces questions about its success rate that some experts say could hinder its chances of getting speedy U.S. and EU regulatory approval.
Several scientists have raised doubts about the robustness of preliminary results showing the experimental vaccine was 90 percent effective in a sub-group of trial participants who received lower doses of the vaccine.
Soriot said he does not expect the additional trial to delay UK and European regulatory approvals.
He acknowledged however that data from the new trial would be necessary for U.S. approval.
“The question for us was, will we need the U.S. data to get approval in the U.S. or can we get approval in the U.S. with international data, and it was never clear. Now with those results, it’s more likely that we will need the U.S. data,” he added.
A peer-reviewed analysis of the trial data will be published in a medical journal in the coming weeks.
AstraZeneca’s COVID-19 vaccine is one of three that could be approved before the end of the year. Both Moderna and Pfizer recently announced that their test trials for their CCP virus vaccines were successful and have more than a 90 percent efficacy rate. Both companies’ vaccines were created using messenger RNA, meaning that it relies on segments of genetic material delivered into cells to help stimulate an immune response.
A setback of mRNA vaccines includes needing to store and distribute them at cold temperatures to prevent them from degrading.
AstraZeneca’s experimental vaccine meanwhile is based on an adenoviral vector that requires only refrigeration and is therefore easier to store, meaning many low- and middle-income countries are relying on it.
Dr. Moncef Slaoui, chief scientific adviser for Operation Warp Speed, said Sunday that vaccinations against COVID-19 in the United States could begin by mid-December.
Reuters contributed to this report.