Antibody cocktail helps prevent coronavirus infections in same households

Illustration of antibodies.
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An antibody cocktail reduced the risk of developing symptomatic COVID-19 by 81% in people living in the same household as a positive case, according to results from a phase 3 trial.

Regeneron Pharmaceuticals monoclonal antibody cocktail is made up of two antibodies designed to block SARS-CoV-2 infection by binding to its spike protein. Under emergency use authorization, Regeneron's antibody cocktail, as well as another one developed by the company Eli Lilly, are already being used to treat COVID-19 patients who aren't hospitalized but are at high risk for developing severe disease, according to The New York Times.

But with the new phase 3 results, Regeneron plans to ask the Food and Drug Administration (FDA) to expand the emergency use authorization of the cocktail to a larger group of people to be used as a way to prevent infection, the company announced in a statement on Monday (April 12). If approved, the cocktail may help to keep unvaccinated or immunocompromised people safe as vaccination efforts continue across the U.S. The findings haven't yet been published in a journal nor have they been peer-reviewed.

Related: Quick guide: COVID-19 vaccines in use and how they work

For the phase 3 trial, the researchers enrolled 1,505 people who were not infected with SARS-CoV-2 but lived in the same household as someone who tested positive for SARS-CoV-2 in the last four days. They gave half of those people a single dose of the antibody cocktail as an injection and half a placebo injection.

They found that 11 patients who received the antibody cocktail went on to develop symptomatic COVID-19 compared with 59 people who received the placebo. What's more, in those who developed symptomatic infections, the cocktail helped people get rid of the virus faster, and they had a shorter duration of symptoms, according to the company statement. Those who were given the cocktail had symptoms for one week, whereas those given the placebo had symptoms for three weeks.

If authorized, the cocktail "could help control outbreaks in high-risk settings where individuals have not yet been vaccinated, including individual households and group living settings," Dr. Myron Cohen, who leads the monoclonal antibody efforts for the National Institutes of Health-sponsored COVID Prevention Network, said in the statement. In January, Eli Lilly announced similar findings for one of the antibodies in its cocktail. When the single antibody was given to nursing home residents exposed to a COVID-19 positive case, the antibody reduced the risk of developing symptomatic disease by 80% when compared with a placebo. 

But these drugs haven't been widely accessible, especially because most patients don't know where to find them or know to ask for them, according to the Times. Also, because the drugs are currently given via intravenous infusions, hospitals and clinics find it challenging to administer the drugs in a timely manner and thus haven't made them a priority, according to the Times. (The company, however, plans to ask the FDA for approval to administer the drug as an injection as it was given in the phase 3 trial).

Originally published on Live Science.

Yasemin Saplakoglu
Staff Writer

Yasemin is a staff writer at Live Science, covering health, neuroscience and biology. Her work has appeared in Scientific American, Science and the San Jose Mercury News. She has a bachelor's degree in biomedical engineering from the University of Connecticut and a graduate certificate in science communication from the University of California, Santa Cruz.