AstraZeneca Plc and the University of Oxford, among the pioneers in the quest to deliver a Covid-19 vaccine, face growing questions about their trial results after acknowledging a manufacturing error.
While an announcement Monday from Astra and Oxford showed their shot was 70% effective on average in a late-stage study, the scant details released by UK partners have raised concerns about whether regulators would approve it. In a later statement, Oxford said a difference in manufacturing processes led some participants to receive half a dose rather than a full dose.
Astra and Oxford said their vaccine was 90% effective when given half a dose before a full-dose booster, and that two full doses showed 62% efficacy. But the director of the US vaccine program known as Operation Warp Speed said the next day that the dose showing the highest level of effectiveness was tested in a younger population and that half the dose was administered to some people due to an error in the amount of vaccine put into some vials. None of this was revealed in Astra’s original statement.
The findings had fueled optimism that the end of the pandemic is in sight and that several vaccines to combat Covid-19 could be ready soon after positive results from Pfizer Inc. and Moderna Inc. Astra and Oxford remain close to the front of the pack, though the way they’ve handled the big test has unsettled scientists and investors, increasing the risk that it will slow them down.
“Every time there is confusion in the lawsuits, it is not a good thing because it effectively takes away any kind of credibility that I had,” said Ketan Patel, fund manager at EdenTree Investment Management. “I think there will be a lot more scrutiny of the Astra product due to the manufacturing problem.”
In its statement, Oxford said that when it became apparent that a lower dose was used, it was discussed with regulators and an agreement was reached to go ahead with the two regimens. “The methods for measuring concentration are already established and we can ensure that all vaccine lots are now equivalent,” according to the university.
An Astra spokesperson said the trials were conducted “to the highest standards” and further analysis is underway to refine the efficacy reading.
Astra shares changed little Thursday after falling 6.2% earlier in the week amid questions about the test results.
‘Unknown’ efficacy
“The most likely explanation for the divergent efficacy in your interim analysis is chance or patient demographics,” wrote Sam Fazeli, an analyst at Bloomberg Intelligence, in a note. “Either way, approval based on current data means that people will be inoculated with a vaccine whose true efficacy is unknown.”
The battle against Covid-19 is at a tipping point and encouraging findings from vaccine trials are expected this month. A vaccine from Pfizer and BioNTech SE and another from Moderna Inc. were 95% effective in preliminary analyzes of trials of tens of thousands of volunteers.
Fazeli added: “We are more convinced by now of the Moderna and Pfizer data.”
.
