Companies test for antibodies to treat and prevent COVID-19

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With a coronavirus vaccine months away, companies are rushing to test what could be the next best thing: drugs that deliver antibodies to fight the virus right away, without having to train the immune system to make them.

Antibodies are proteins that the body makes during infection; they attach to a virus and help eliminate it. Vaccines work by tricking the body into thinking there is an infection, so it makes antibodies and remembers how to do it if the real bug appears.

But it may take a month or two after vaccination or infection for the most effective antibodies to form. Investigational drugs shorten this process by giving concentrated versions of specific drugs that work best against the coronavirus in laboratory and animal tests.

“A vaccine takes time to work, to force the development of antibodies. But when you donate an antibody, you get immediate protection, ”said University of North Carolina virologist Dr. Myron Cohen. “If we can produce them in high concentrations, in large vats in an antibody factory … we can sort of bypass the immune system.”

These drugs are thought to last a month or more and could give quick and temporary immunity to people at high risk of infection, such as health workers and roommates of someone with COVID-19. If they prove to be effective and if a vaccine does not materialize or protect as hoped, the drugs could eventually be considered for wider use, perhaps for teachers or other groups.

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They are also being tested as treatments, to help the immune system and prevent severe symptoms or death.

“The hope is to target people who are in the first week of their illness and that we can treat them with the antibody and prevent them from getting sick,” said Dr Marshall Lyon, an infectious disease specialist helping test one of these drugs. at Emory University in Atlanta.

Having such a tool “would be a really momentous thing in our fight against COVID,” Cohen said.

Vaccines are seen as a key to controlling the virus, which has been confirmed to have infected more than 20 million people worldwide and killed more than 738,000 people. Several companies are rushing to develop vaccines, but the results of the major final tests needed to evaluate them are months away.

Antibody drugs are “very promising” and, on the other hand, could be available “quite quickly,” said Dr. Janet Woodcock, a U.S. Food and Drug Administration official who is leading government efforts to accelerate COVID-19 therapies . Key studies are underway and some answers should be provided in early fall.

One company, Eli Lilly, has already started manufacturing its antibody drug, betting that ongoing studies will yield positive results.

“Our goal is to get something out as soon as possible” and to have hundreds of thousands of doses ready by the fall, said Lilly’s scientific director Dr Daniel Skovronsky.

Another company that has developed a cocktail of antibody drugs against Ebola – Regeneron Pharmaceuticals Inc. – is currently testing one for the coronavirus.

“The success of our Ebola program gives us some confidence that we can potentially do it again,” said Christos Kyratsous, a Regeneron microbiologist who helped lead this work.

Regeneron’s medicine uses two antibodies to increase the chances that the medicine will work even if the virus evolves to escape the action of one.

Lilly is testing two different single antibody drugs – one with the Canadian company AbCellera and the other with a Chinese company, Junshi Biosciences. In July, Junshi said that no safety concerns had appeared in 40 healthy people who had tried it and that larger studies were underway.

Others working on antibody-based drugs include Amgen and Adaptive Biotechnologies. Singaporean biotechnology company Tychan Pte Ltd. is also testing an antibody drug and has similar products in development for Zika virus and yellow fever.

“I am cautiously optimistic” about the drugs, said the nation’s leading infectious disease specialist, Dr Anthony Fauci. “I am comforted by the experience we had with Ebola”, where the drugs have been shown to be effective.

What could possibly go wrong?

– Antibodies may not reach all the places where they need to work, such as deep in the lungs. All antibody drugs are given intravenously and must find their way into the bloodstream to where they are needed.

– The virus can mutate to avoid the antibody – the reason why Regeneron is testing a combo of two antibodies that binds to the virus in different places to prevent its escape.

Skovronsky said Lilly was sticking with one antibody because the manufacturing capacity would essentially be cut in half to make two, and “you’ll have fewer doses available.” If just one antibody works, “we can treat twice as many people,” he says.

– The antibodies may not last long enough. If they go away within a month, treatment is still acceptable because COVID-19 disease usually goes away by that time. But for prevention, it may not be practical to give infusions more often than every month or two.

A San Francisco company, Vir Biotechnology Inc., claims it has engineered antibodies to last longer than usual to avoid this problem. GlaxoSmithKline has invested $ 250 million in Vir to test them.

Giving a higher dose can also help. If half of the antibodies go away after a month, “if you give twice as much, you’ll have two months of protection,” Lilly’s Skovronsky said.

– The Great Fear: Antibodies can do the opposite of what is hoped for and actually improve the ability of the virus to enter cells or boost the immune system in a way that makes people sicker. This is a theoretical concern that has not been seen in testing until now, but definitive large experiments are needed to prove safety.

“As far as we can tell, antibodies are helpful,” Lyon said.

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Marilynn Marchione can be followed on Twitter: @MMarchioneAP

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The Associated Press’s Department of Health and Science receives support from the Department of Science Education at the Howard Hughes Medical Institute. The AP is solely responsible for all content.

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