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Great news on Covid vaccine as Oxford trial shows dual immune action against coronavirus

Oxford vaccine is at the front of 160 coronavirus vaccines in various stages of development. AstraZeneca may begin delivering doses to UK as early as September.

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London: A coronavirus vaccine the University of Oxford is developing with AstraZeneca Plc showed promising results in early human testing, and is now set to move into larger trials that are likely to be decisive on how effective they truly are.

The results weren’t enough to convince the market, however. AstraZeneca Plc fell from a record high in New York trading on concerns over whether its vaccine can match the progress seen in programs from Pfizer Inc. and BioNtech SE, as well as Moderna Inc.

“In the competitive context they fail to impress,” said Bernstein analysts led by Ronny Gal.

The vaccine increased levels of both protective neutralising antibodies and immune T-cells that target the virus, according to the study organisers. The results, published Monday in The Lancet medical journal, are a key milestone for one of the fastest-moving vaccine projects globally.

“Our hope is that we can actually start delivering a vaccine before the end of the year,” AstraZeneca Chief Executive Officer Pascal Soriot said on a call. “We’re working as quickly as we can but of course there are things you cannot control.”

Exacerbating market concerns, The Lancet publication came just an hour after Pfizer and BioNtech had announced early positive data from their Covid-19 vaccine trial in Germany, which builds upon promising results from their program earlier this month.

AstraZeneca’s US-traded shares fell 4 per cent at 2:07 pm. in New York trading.

Sarah Gilbert, a vaccinologist who leads the work at Oxford, said 18-to-55 year olds and people over 55 in the UK trial are already being given two doses of the vaccine candidate. The larger US trial due to start in a few weeks will also likely test two doses, she said.

“We are seeing very good immune responses, not just on neutralising antibodies but of T cells as well,” said Adrian Hill, head of Oxford’s Jenner Institute, in an interview. “We’re stimulating both arms of the immune system.”

The results will be closely scrutinized as governments around the world seek to end a pandemic that’s killed more than 600,000 people and triggered economic turmoil since erupting earlier this year.

Also read: Covaxin trial process has begun, can get results in 2-3 months if all goes well, says AIIMS

Best strategy

“We don’t know where we need to get to with the immune response,” Gilbert said by telephone. “Nobody knows how strong it needs to be.”

The best strategy, she said, is to go for a strong immune response to determine efficacy, she added. “If it turns out to be too much, that’s fine,” Gilbert added. “We may be able to take it back to one dose at least for the younger adults.”

The testers are also looking at different dose levels” to determine the best way forward, she said.

A positive outcome had been widely expected after reports last week lifted the stock, with the vaccine already in more advanced trials. Researchers plan to prioritize testing a two-dose regimen, rather than a single shot, dampening some of the enthusiasm over the vaccine, which they’ve previously said they hoped to deliver as early as September.

Also read: T cells produced, mild side effects — decoding why Oxford’s vaccine offers new Covid hope

Key step

Although stimulating production of neutralizing antibodies doesn’t prove a vaccine will be effective, it’s considered an important early step in testing. Results from testing in animals had already shown the Oxford-AstraZeneca shot provoked an immune response.

Across the world, about 160 coronavirus vaccines are in various stages of development, according to the World Health Organization. The Oxford shot is close to the front of the pack and has already begun final-stage tests. AstraZeneca has said it may begin delivering doses to the U.K. as early as September.

“We want other companies to have vaccines that work as well because the world will get more vaccine sooner,” Hill said. “We just feel there is an advantage of having both arms of the immune system stimulated well.”

The British drugmaker received a boost when the U.S. pledged as much as $1.2 billion toward development. Under its agreement with Astra, the U.S. could begin receiving supplies as early as October.

The U.K. has also struck a supply agreement for the shot, but on Monday it secured access to other drugmakers’ experimental vaccines to hedge its bets and garner enough doses to cover its population of 66 million. The government secured deals with Pfizer Inc., BioNTech SE and Valneva SE.

Covid fight

Companies and universities are relying on an array of approaches in the fight against Covid-19. The Oxford team has developed a technology that can speed up the process by using a harmless virus to carry some of the pathogen’s genetic material into cells to generate an immune response. The proposed vaccine is made from a weakened version of a common cold virus that’s genetically changed to make it unable to grow in humans.

Oxford has inserted genetic material from the surface spike protein of the SARS-CoV-2 virus as a way of tricking the immune system into fighting back. The platform stimulates both antibodies and high levels of killer T-cells, a type of white blood cell that helps the immune system destroy infection.

“We’re very encouraged,” Hill said. While the test doesn’t prove the vaccine will work, “I think we’re a bit more confident it should work this week than last week.”

Moderna’s initial results were from the first group of 45 patients who received the vaccine Moderna’s shares surged in U.S. trading after the results, despite a high rate of side effects among the patients who got the shot.

The Oxford shot elicited neutralizing antibodies after a single dose, Hill said. That may be an important advantage in quickly raising immunity.

“I don’t read that clearly in the Moderna data,” he said. “I think they need two doses to see plausibly protective neutralizing antibodies.“

A large trial is set to begin this month that will test Moderna’s vaccine in a two-shot regimen. Astra will also prioritize a two-shot regimen, Hill said.

“It gives higher titres of antibodies, which is important going forward,” he said.- Bloomberg

Also read: UK company Synairgen declares clinical trial of protein treatment for Covid as successful


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