AstraZeneca may expand US trial to seek 90% effective vaccine

AstraZeneca’s (AZN) positive interim results for its COVID-19 vaccine on Monday sparked some confusion as health experts and Wall Street tried to parse claims of the vaccine’s ‘up to 90%’ effectiveness. and “70% on average” of society.

The candidate vaccine was tested in two different ways, resulting in two different efficacy rates – 62% and 90% – which the company has averaged at 70%. The lowest efficacy came from two full doses given one month apart, the highest efficacy came from the first dose halved followed by a full booster.

But it has baffled health experts and angered some analysts.

“I am completely surprised. I don’t understand it,” said Dr. Arthur Caplan, a leading bioethicist and professor at New York University Langone Medical Center, explaining why the company chose to test both diets so late in the game and why the weaker rpm provided a stronger rpm. protection.

He was not alone. Other top vaccine experts like Dr. Peter Hotez of Baylor College of Medicine and Dr. Paul Offit of Children’s Hospital of Pennsylvania made similar claims in interviews with Yahoo Finance on Monday.

“It’s science by press release and it’s really hard to know what’s going on,” Offit said.

What do the numbers mean?

The 62% efficacy of a full-dose regimen was intriguing to many, with some wondering if previous concerns about an adenovirus vector platform – which AstraZeneca and some Chinese vaccine candidates use – were in game. Johnson & Johnson also uses a similar platform, but the same problem is unlikely to arise, some experts said.

Unlike Pfizer (PFE)/BioNTech (BNTX) and Moderna (MRNA), which use a new synthetic technology called messenger RNA, AstraZeneca uses synthetic coding in an inactive virus to deliver the vaccine.

Hotez speculated that the first shot induced more antibodies that inhibited a second dose. Adenovirus vaccines can sometimes immunize the body against a second injection of the same vaccine.

But even with lower efficiency than Pfizer and Moderna, which are both around 95%, Hotez noted that the true efficiency is still unknown.

“These efficacy numbers may fluctuate as we vaccinate the entire US population,” he said.

SVB Leerink analysts were less forgiving, saying AstraZeneca and its partner Oxford University embellished the results to show higher efficiency.

“The inventors’ suggestion that the small sample that received the lower priming dose was evidence of higher efficacy only brings the program into disrepute,” said analyst Geoffrey Porges.

He added: “It appears that the occurrence of pre-existing or post-vaccination immunity to the vector has a significant moderating effect on vaccine efficacy.”

NYU’s Caplan noted that even with published data from any vaccine trial, much still remains unknown about vaccines.

Which age group, ethnicity or disease state does or does not work with a specific vaccine, as well as the durability of protection and the ability to block transmission remain unknown, he said.

Which means that while regulators globally are gearing up to assess the data, there’s still a lot to know.

Porges said: “We consider the release of the data to be premature and insufficient.”

The company will submit for emergency use to the World Health Organization, allowing low- and middle-income countries to have a candidate vaccine that does not require special shipping and handling.

Other SVB Leerink analysts said so on Monday.

“Despite an apparent inferiority to mRNA-based drugs, we believe certain attributes of the program are important, particularly during the first wave of vaccines at the height of the pandemic, where demand will significantly outstrip supply,” they said.

AstraZeneca says late-stage trials of its COVID-19 vaccine have been “very effective” in preventing the disease. A vaccine developed by AstraZeneca and the University of Oxford prevented 70% of people from developing the coronavirus in late-stage trials, the team reported Monday, Nov. 23, 2020. (Oxford University Pool via AP, File)

Double by halving the dose

AstraZeneca’s US head Ruud Dobber told Yahoo Finance that the company will engage with the US Food and Drug Administration (FDA) to discuss the US trial and possibly add a new arm in the process. late-stage trial to include half-dose primer.

“Overall, I think the data set is very comprehensive and very positive,” Dobber said.

Asked about the reason for the change in dosage and why the higher dose was not as effective, AstraZeneca declined to comment. An executive told the Guardian the half dose was an accident. But why this resulted in greater efficiency remains unknown.

But it’s clear the company is excited about this finding and intends to pursue the full-half-dose booster regimen in ongoing trials.

In an emailed statement on Tuesday, a spokesperson said: “We see a lot of merit in this regimen and will now enter into discussions with regulators to incorporate this combination of doses for further clinical investigation. We will continue to follow the science to better understand this data and share it in a peer-reviewed journal in due course. »

In a Tuesday briefing, Operation Warp Speed ​​chief Moncef Slaoui said the US trial, which recruited only 11,000 people, or about a third of its target participants, only tested than the full two doses. He also noted that those who received the half dose in other trials were under 55 years old.

Meanwhile, Dobber said data from the trials in the UK and Brazil will be published by the end of this week and have been submitted to a peer-reviewed journal.

Of the leading contenders, the company is the only one so far to promise no profit from its vaccine amid the pandemic. The price is around $3 per dose, compared to around $20 and up for mRNA candidates.

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