On a Saturday afternoon in March, as COVID-19 was on its way to New York, a dozen scientists crowded around a computer in the lab of a suburban drug company. They spent weeks receiving blood from the world’s first survivors and from mice with human-like immune systems – all to test thousands of potential treatments.
Now was the time for results.
The screen displays totals of bright green dots, hundreds or thousands in most samples. Then they saw a few dozen, a few two, and finally zero.
The researchers cheered, and their boss sent champagne.
No dots meant infected cells. Scientists have found antibodies that block the coronavirus.
This was the beginning of a drug that would eventually fall into the arms of an American president and others fighting COVID-19.
Antibodies are substances that the immune system makes bind and help eliminate a virus, but it takes a few weeks after infection or vaccination for the most effective to form. Drugs like the one developed by scientists at Regeneron Pharmaceuticals Inc. are intended to help immediately by providing concentrated doses of one or two of the best-functioning antibodies.
The drugs, given by IV, are tested to prevent infection in people at high risk of doing so, who may not yet receive a vaccine, such as colleagues of patients with COVID-19. They are also tried as a treatment shortly after infection to avoid serious diseases.
These are some of the most complex drugs that exist, made in a tiring, high-tech process, with the risk of ruin at every step. Unlike chemicals that are simply mixed in a laboratory, antibodies are captured from living cells. The companies used cells from an entire household – monkeys, hamsters, mice, horses, cows, blades.
Each drug starts with a single coronavirus survivor.
Eli Lilly, for example, worked with AbCellera, a Canadian company that obtained a strong antibody from an early case there. GlaxoSmithKline and Vir Biotechnology found one frozen in blood for years in a Swiss laboratory from a survivor of SARS, another coronavirus that caused a deadly outbreak in 2003.
Regeneron with two antibodies is unique: one came from a COVID-19 survivor in Singapore, and the other from the company’s genetically modified mice.
People produce hundreds or thousands of types of antibodies after infection, but “most of them are not very good” at blocking the coronavirus, said Christos Kyratsous, a microbiologist who helped run Regeneron. “Look for the needle in the hay” to find one to do it, he said.
The search began in January, when Chinese scientists identified the new virus. Dr. Sumathi Sivapalasingam, a Regeneron scientist who worked at the U.S. Centers for Disease Control and Prevention, began looking for blood samples from people who had been infected from the beginning, long enough to produce antibodies. good.
“We were basically calling people from all over the world” – China, Thailand, the United Kingdom, Europe – out of luck, she said.
Suddenly, they received a phone call from Dr. David Lye at the National Center for Infectious Diseases in Singapore. He knew that Regeneron had antibodies to Middle East respiratory syndrome or MERS, a similar coronavirus disease. COVID-19 cases were beginning to mount and “I was thinking about what else to do,” because no treatments had been proven to help, Lye said.
The scientists quickly ruled out the use of MERS antibodies, but agreed to look for some for the new virus. Lye asked three of his patients – two men and a woman who had recovered from COVID-19 pneumonia – to donate blood.
He was healthy. The blood cells survive for about two days, and the flight to New York lasts 18 hours. The samples should then be cleared through customs and taken to the Regeneron Laboratory in Tarrytown, New York.
“It was exciting, but terrifying,” Lye said. “I was worried if the flight delay or any mistake along the way would make the evidence unnecessary.”
“The blood was hot in the tube” when a courier took him to the Singapore airport, Sivapalasingam said.
He arrived on March 13, the day COVID-19 was declared a national emergency in the United States. Sivapalasingam was working late at home when he received an e-mail from colleagues in the laboratory.
“They jumped for joy because the cells were fresh and viable and perfect,” she said.
Meanwhile, others were working on what Regeneron’s chief executive calls “his magic mice,” animals raised to have human-like immune systems. When they are vaccinated with some of the virus, they do not get sick, but they produce “antibodies almost identical to what humans would do,” Kyratsous said. It takes only 20 to 30 of these mice to develop a drug.
The blood from mice and patients contains B cells and each produces a specific antibody that is transported to its surface. The goal is to find antibodies that stick to the virus and prevent it from infecting the cells.
The scientists first examine the B cells by mixing them with some of the prickly protein that covers the virus and sorting the cells with antibodies that connect. The researchers then decode the genetic recipes for each antibody. Genes are introduced into a type of hamster cell widely used in the drug industry because they grow very quickly and produce the chosen antibody, such as mini-biofactories.
Then comes the big challenge: testing each antibody by mixing it with uninfected cells and a “pseudovirus” – a tamed virus that has been modified to carry spike protein and shine green if it enters a cell.
Each antibody enters a well in a plastic container, with a grate, like a massive tray for ice cubes. A computer attached to a microscope counts how many cells in each well are infected to see how well the virus has blocked each antibody.
These are the results obtained by Kristen Pascal on Saturday, March 14 at the laboratory.
She recalled that she “brought pizza and pie for Pi Day,” a day when scientists celebrate because 3, 1, and 4 are the first three digits of pi, an important number in math.
Kyratsous, other managers, and the company’s co-founder, Dr. George Yancopoulos, floated behind her chair as the computer counted bright spots.
“I probably get 1 and 2,000 green spots in each well,” then some hit 10 and some hit two, she said. When they saw some zeros, Yancopoulos ordered champagne.
“I had very, very good antibodies,” she said. “I knew we were in good shape, that we could actually make a difference.”
These antibodies come only from mice. Two weeks later, the trial was repeated on human evidence in Singapore.
In total, Regeneron tested more than 3,300 antibodies – pitting the finalists against each other as gladiators in the lab – before choosing two that bind to the peak protein at different points to make it more difficult to evacuate the virus.
“There was a huge sense of relief because you selected the best antibodies … but it was very, very stressful because you can’t go back,” Kyratsous said. “These are the ones that will go into production.”
Dan Van Plew’s job is to take what he calls the “recipe” from the Tarrytown lab, put it through the “test kitchen” at Regeneron’s production facility near Albany, New York, and learn how to mass-produce it as drug. It’s like creating some artisanal cupcakes for a tasting and then getting a big wedding order, “so now I have to figure out how to make a thousand for a VFW room,” he said.
First, the fast-growing hamster cells that contain the genetic prescription for the chosen antibody are placed in a container called a bioreactor. “You try to imitate a body,” keeping the cells at body temperature, boiling in the air to provide oxygen, removing carbon dioxide, and providing nutrients at the right rate so that the cells can multiply, he explained.
These are gradually moved into larger and larger bioreactors – “it looks like a really big microbarrier,” Van Plew said – until the cells are so densely packed that they go from reproduction to antibody production.
Contamination is a constant risk.
“At any given time, I probably have 1,500 people touching the process, either touching the product or running a biorector” and every car I drive, the shoe I wear or what I touch is a potential danger, he said.
When the final work of the bioreactor is finished, the contents are purified to remove pieces of cells, so that all that remains is the antibodies, which are packed in vials.
The production lasted 45 days – “the speed of light compared to the standard process”, which is usually three to five months, he said.
Human studies began in early June. In October, President Donald Trump received the drug under the terms of “compassionate use,” but there is no way to know if it did him any good, as most patients recover on their own and have received other experimental treatments. The Food and Drug Administration has allowed the emergency use of Regeneron and Eli Lilly antibodies to mild and moderately ill patients who do not need hospitalization while studies continue. Tests in more seriously ill hospitalized patients have been discontinued amid concerns that the drugs may not help in this situation.
Regeneron sells other antibodies to heart disease, cancer and other conditions. The MERS outbreak in 2012 was the first time he tried to quickly contract an infectious disease. MERS proved not to spread easily from person to person, “so as a company we were very lucky,” and the company never expanded production, Kyratsous said.
When Ebola struck in 2014, Regeneron developed antibodies and made its first production in an outbreak situation. But it lasted nine months and until then the cases were decreasing. Another focus was needed in 2018 to demonstrate the value of the drug.
When the new coronavirus appeared, many of the same scientists were waiting.
“I knew exactly what to do … I’ve done this before,” Kyratsous said. “I feel like Regeneron was waiting for a moment like this.”
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Marilynn Marchione can be followed on Twitter at http://twitter.com/MMarchioneAP
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The Associated Press Department of Health and Science receives support from the Howard Hughes Medical Institute’s Department of Science Education. AP is solely responsible for all content.