AstraZeneca’s coronavirus vaccine is coming under intense scrutiny after its UK scientists made a major “mistake” during trials — one that could even halt it from getting approved, according to reports.
The UK drugmaker and its partner, Oxford University, admitted — after reporting its vaccine tested up to 90% effective — that the promising results came after a batch of volunteers were accidentally given half doses. The efficacy of the vaccine was significantly lower at 62% for those who received the correctly administered two full doses.
Lead researcher Mene Pangalos insisted it was “serendipity,” but the error, which was not reported in the initial findings, has brought the vaccine under intense scrutiny from scientists and industry experts.
The half-dose group was just 2,741 volunteers — and all were under 55, raising questions as to whether the relative youth of the participants created the positive results, not the size of the dose.
“It pains me to say this, but… I think the claims made for the Oxford/AstraZeneca Covid-19 vaccine are on very shaky ground. We should wait for a solid large trial,” scientist Hilda Bastian tweeted after the testers’ confessions.
“They have solid data for a relatively weak vaccine and weaker data for a relatively strong one,” he warned of the low numbers accidentally given the half-dosage.
“This is really not being handled well at all … it’s a good thing this wasn’t the first vaccine to read out,” he added, referring to earlier vaccine test announcements from Pfizer and Moderna.
The former head of research and development at one of those rivals, Pfizer, questioned whether it would derail the AstraZeneca vaccine getting approved.
“Hard to believe that the [US Food and Drug Administration] will issue [emergency use] for a vaccine whose optimal dose has only been given to 2,300 people,” Dr. John LaMattina tweeted. “More data for this dosing regiment will be needed.”
Natalie Dean, a biostatistician and an expert in vaccine trial design at the University of Florida, gave the UK team “a poor grade for transparency and rigor.”
“It is awfully confusing for experts and non-experts alike,” she wrote.
The error and confusion over results caused shares in the company to slump 6.2 percent as industry experts also lose confidence, according to Bloomberg News.
“Any time you have confusion in trials it’s not a good thing because it effectively removes any kind of credibility you had,” Ketan Patel, a fund manager at EdenTree Investment Management, told Bloomberg.
“I think there will be a lot more scrutiny of Astra’s product due to the manufacturing issue.”
Geoffrey Porges, an SVB Leerink analyst, was another to predict that it could be enough to prevent the FDA from approving the vaccine for use.
“I don’t believe that the FDA will look positively at any trial where the dose, or the age cohorts, or any other variable were changed mid-trial, inadvertently or deliberately,” Porges told Bloomberg News. “I think that they have really damaged confidence in their whole development program,” he told The Times.
Other experts are also concerned at the suggestion that the low-dose group raised the overall effectiveness to 70%.
“You’ve taken two studies for which different doses were used and come up with a composite that doesn’t represent either of the doses,″ said David Salisbury, an associate fellow of the global health program at the Chatham House think tank. “I think many people are having trouble with that.″
A spokesman for Astra told Bloomberg that the trials were conducted “to the highest standards” and more analysis is being done to refine the efficacy reading.