This therapy is thought to provide temporary immunity for at least a couple of months and treat those who are infected and experiencing symptoms. Scientists study plasma from recovered patients to identify which types of antibodies work best against the coronavirus. Then they’re mass-produced in a lab, and those winning antibodies are packed into an injectable treatment.
The pharmaceutical company Regeneron has produced one of the most promising options, which is currently being tested in patients across the United States, according to The New York Times. President Donald Trump was given a single dose of the treatment this week after he tested positive for COVID-19.
Preliminary findings show that the injection may reduce the load of the virus in the body and potentially reduce time spent in the hospital if taken early enough during an infection. Trump’s use of the experimental treatment was granted as a “compassionate use case,” in which drug companies allow patients to use a treatment outside of a clinical trial. The Food and Drug Administration also approved giving Trump the injection.
The CEO of Regeneron has known Trump casually for a few years, The New York Times reported.
Other medical companies are working on their own antibody cocktail treatments.
New York’s Mount Sinai Health System revealed in May that it teamed up with drugmaker Sorrento Therapeutics Inc. to create a cocktail that could protect someone against the coronavirus for up to two months.
Eli Lilly reported promising results in September for a COVID-19 antibody treatment.
There’s still a way to go before it’s determined if these treatments will be effective solutions, but health experts are excited to potentially have another option in the fight against COVID-19. Here’s what you should know about this potential treatment.
Antibodies protect us from infection.
You may already be well-versed in the role antibodies play during an infection, but here’s a quick recap. When a person is exposed to a virus like SARS-CoV-2 (the official name of the virus that causes COVID-19), their immune system turns on and starts working to get rid of the virus.
During that process, it makes antibodies — a type of protein that neutralizes or deactivates the virus, preventing it from spreading or making copies of itself.
After an infection clears up, those antibodies linger in the bloodstream for a while, so if the virus ever makes a reappearance, the antibodies already know how to swiftly knock out the invader. While it’s not a guarantee that all antibodies are neutralizing and provide long-term protection against reinfection, many do.
This is part of the reason why researchers are so interested in studying the plasma of recovered COVID-19 patients and why antibodies are the main target in the creation of a vaccine. People who have already battled COVID-19 may have antibodies for some time following recovery, and scientists want to know which antibodies provide protection, and if so, for how long.
Here’s how antibody cocktails work.
Antibody cocktails aren’t the same as the plasma transfusions you may have read about (where recovered patients are donating their antibody-rich plasma, also called convalescent plasma, which is then infused into the blood of people actively fighting COVID-19).
With antibody cocktails, researchers first identify the antibodies in people’s plasma that work best against a specific virus, then they synthetically produce copies of them in a lab.
“When you’re using convalescent plasma, you’re basically giving all the antibodies that people have. But when you’re using antibody cocktails, you’re basically using two or three specific antibodies … that are very specific for this virus, so it’s a much more targeted therapy,” said Dr. David Rosenthal, the medical director at Northwell Health’s Center for Young Adult, Adolescent and Pediatric HIV.
Antibody cocktails contain around two or three types of antibodies that bind to different parts of a virus and “act synergistically,” Zapata added.
This is super helpful if a virus were to mutate (which the coronavirus has done already). Even if one part of the virus mutates, rendering one type of antibody useless, there will still be at least one other type of antibody that could bind to another part of the virus and prevent it from replicating itself or binding to another cell.
“This is also why using a cocktail of three antibodies would be better than just using one antibody,” Zapata said.
Even if a vaccine were to become available soon, antibody cocktails are an important piece in the puzzle. Not everyone’s immune system will respond well to a vaccine and mount a response (e.g., the influenza vaccine is often less effective in older adults). This could theoretically give those people another option.
“An antibody cocktail would still be of use in those patients that still got sick from the virus despite vaccination,” Zapata said.
Antibody cocktails have been hit-or-miss with other viruses.
Antibody cocktails have been around since the 1980s, Zapata said. They’ve been developed for viruses like HIV and certain cancers, as well as lupus and multiple sclerosis. Scientists also designed a cocktail for Ebola, and research on monkeys found it to be somewhat (but not totally) effective.
Overall, it’s kind of a new area, Rosenthal said. Though preliminary data shows antibody cocktails work well in some cases, other antibody cocktails haven’t worked well at all.
Antibody cocktails can be challenging to make for viruses that like to mutate. For example, scientists have struggled to design a reliable antibody cocktail for HIV because the HIV virus mutates again and again. We still don’t have a clear grasp on the behavior of SARS-CoV-2, so while it’s intriguing, there’s no guarantee a cocktail could even work for COVID-19.
“This is a very exciting technology and provides some very interesting options for the future, but it hasn’t widely been used for other infectious diseases and its had results that are kind of hit-or-miss before,” Rosenthal said.
Like any treatment, there’s always going to be risks, benefits and alternatives, Rosenthal noted.
While some patients will respond well to antibody cocktails and recover, others will not, according to Zapata. Additionally, while they can be extremely effective, antibodies can also backfire and make it easier for a virus to enter and infect cells, Zapata added.
Some people may experience an allergic reaction if the antibodies are developed in other animals. The antibodies could also bind to the wrong site in the body and trigger adverse effects, Rosenthal said.
There is still a lot of research to do.
The prospect of having a potential treatment and protection against COVID-19 is exciting, but there’s still a lot of research to be done on antibody cocktails.
For one, researchers need to identify the types of antibodies that are neutralizing (remember, not all of them are) along with which part of the coronavirus they bind to so they can make a well-rounded cocktail.
They also need to figure out how long the antibody cocktails can provide immunity for — and how that varies from person to person ― via clinical trials.
“We need to make sure we’re really taking a look at patients getting the therapy and patients not getting the therapy to understand if there is a medical benefit,” Rosenthal said.
Antibody cocktails potentially give us another solid option to work with, especially as we wait for a vaccine.
“The exciting thing about using antibody cocktails is they provide the potential to very specifically prevent transmission of COVID and possibly help people that are already infected,” Rosenthal said. “But, they’re very early on in design and we have a lot of work to continue to do to understand if they really can make a clinical impact.”
This story has been updated to include recent information about the Regeneron treatment and Trump’s COVID-19 diagnosis.
Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.