Questions raised about AstraZeneca-Oxford vaccine data

Anxiety is growing as Oxford University and AstraZeneca process early readings from coronavirus vaccine trials. This may be because many developing countries rely on a break from the pandemic.

The results were praised for successfully showing an average effectiveness of 70%. This is a number achieved by pooling results from a cohort of two different dosing regimens.

One set of participants received the same dose twice a month, and the other group received half the dose and then the full dose. The effectiveness of the first larger group was 62%. In the second subgroup, it was 90%.

It became clear that half-dose administration started with a mistake. It was then given to fewer participants than those who received two full doses, and the discovery of its greater effect seemed like a lucky break.

But on Tuesday, Monsef Slawi, head of Operation Warpspeed, a U.S. government-funded program for vaccine development, revealed that the second subgroup was also limited to people under the age of 55. ..

Oxford and AstraZeneca did not reveal a breakdown of ages on Monday when the results were announced.

“There are a lot of variables we need to understand,” Slawi said. He added that it is still possible that the difference in effectiveness was “random.”

The market is paying attention. AstraZeneca’s London-listed stock has fallen by more than 6% since its announcement. By comparison, Pfizer and BioNTech’s shares have increased by 6% and 14%, respectively, since the results of their vaccine trials were announced earlier this month, showing 90% efficacy. Moderna has increased by 11% since the release of vaccine trial data. This is in addition to the significant increase towards publication.

Geoffrey Porges, an analyst at SVB Leerink, one of the earlier critics of the week, said in the United States after AstraZeneca “tried to” decorate the results “by emphasizing higher effectiveness in a relatively small subset.” I thought it was unlikely to get approval. ” Of the study subjects. ”

John Lamatina, former president of Pfizer’s Global R & D Unit, wrote: twitter It was “unbelievable” for US regulators to issue an emergency license for a “vaccine with optimal doses given to only 2,300 people.”

Much of the confusion is due to Oxford and AstraZeneca not being fully announced due to two different dosing regimens. This changed unexpectedly as the trial progressed.

In a statement late Wednesday, Oxford acknowledged that the difference between the manufacturing and measurement processes meant that half the dose was mistakenly administered, rather than the full dose, later in the clinical study.

According to a statement on Wednesday, this was discussed with regulators at the time, who agreed to use two study regimens. “A method for measuring concentrations has been established that allows all batches of vaccines to be equal,” he said.

UK study participant Richard Lawson is still unaware of whether the vaccine or placebo was given because the study was not yet blinded, but was informed of the mistake in July before getting a booster shot. I told the Financial Times.

As a rule, vaccinologists usually still aim for the lowest effective dose, but the effectiveness of low doses has not yet been explained.

Pascal Soriot, AstraZeneca’s CEO, told Bloomberg News Thursday that the company will conduct an “additional study” to see different efficacy rates.

“Now we have found something that looks like a better effectiveness that we have to verify, so we need to do additional research,” said Solriot.

In response to a request for comment on the Bloomberg interview, AstraZeneca said late Thursday: “As I contacted earlier this week, there are significant benefits to continuing to investigate half-dose / full-dose regimens.”

The company is further evaluating the data, working with regulators on the best approach to doing so, and “adding to data from existing trials” currently being prepared for submission to regulators. Said.

Professor Sara Gilbert of the University of Oxford states that lower initial doses can stimulate the immune system in a way that better mimics natural infections. However, there is no precedent for other vaccines to be administered in this way.

“We don’t have all the information we need to determine if these results are reliable,” said Natalie Dean, an assistant professor of biostatistics at the University of Florida. “We certainly don’t have enough information in the public domain to determine if this half dose is really working.”

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Professor Dean contrasted AstraZeneca’s disclosure with that of other trials. “This precedent was set by Moderna and other vaccines using Pfizer / BioNTech. These were single trials and the protocol was pre-released,” she said. “We had the opportunity to look it up … it was pretty easy.”

There are also concerns about the differences in Oxford vaccine trials in different countries. There were differences not only between different dosing regimens, but also between controls in different countries. In the United Kingdom, participants who did not receive the Covid-19 vaccine received the meningococcal vaccine. In Brazil, they got a saline placebo.

These discrepancies have led to the suggestion that the data are too patchy to be combined into a single compelling effectiveness result.

AstraZeneca spokesman defended the trial, stating that it was “implemented to the highest standards” and met key efficacy endpoints. The company states that more data will continue to be accumulated, additional analysis will be performed, efficacy readings will be improved, and the period of time the vaccine will be protected from the virus will be established.

The results were published in a peer-reviewed journal and regulators set the effectiveness threshold at 50%. This means that 70% effective jabs will continue to be approved.

Despite the question of efficacy, the Oxford / AstraZeneca vaccine offers some obvious benefits. It is cheaper than Moderna and Pfizer / BioNTech mRNA vaccines and can be stored in the refrigerator instead of the freezer.

Oxford University said it “fully” understood the interest in finding medication mistakes and switching medication tactics, approved by UK regulators.

“Because this is a complex scientific discipline, our scientists want to wait for an interim phase 3 peer-reviewed publication to be published at The Lancet. [medical journal] We expect this to be in the coming weeks before we discuss this further. “

Additional report by Hannah Kuchler in New York and Kiran Stacey in Washington

Questions raised about AstraZeneca-Oxford vaccine data

Source link Questions raised about AstraZeneca-Oxford vaccine data

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