In November, the Food and Drug Administration authorized emergency use of the monoclonal antibodies for treating patients with mild or moderate COVID-19 who are at high risk of developing more severe disease that requires hospitalization. Clinical trial data as well as anecdotal information from communities suggest that the monoclonal antibodies might prevent the worsening of symptoms and keep patients out of the hospital.

The US Department of Health and Human Services has signed agreements with Regeneron to buy about 300 000 courses of its casirivimab and imdevimab combination treatment and with Eli Lilly and Company to buy about 3 million courses of its bamlanivimab therapy if needed.

"We are particularly excited to begin studies of REGN-COV2, which is a novel antibody cocktail targeted specifically against SARS-CoV-2," said trial investigator Dr. Suraj Saggar, Chief of Infectious Disease at Holy Name Medical Center in Teaneck, New Jersey. "Over the last long months, we have learned that repurposing existing medicines unfortunately does not offer a broadly effective solution for COVID-19. For this reason, we need to investigate custom-designed approaches like REGN-COV2. The first studies will evaluate if REGN-COV2 can improve disease outcomes in both hospitalized and non-hospitalized patients with COVID-19"said George D. Yancopoulos, M.D., Ph.D., Co-Founder, President and Chief Scientific Officer of Regeneron. 

In November 2020, the antibody cocktail received an Emergency Use Authorization (EUA)
from the U.S. Food and Drug Administration (FDA) for the treatment of mild to moderate
COVID-19 in adults, as well as in pediatric patients at least 12 years of age and weighing at
least 40 kg, who have received positive results of direct SARS-CoV-2 viral testing and are
at high risk for progressing to severe COVID-19 and/or hospitalization. The clinical
evidence from Regeneron’s outpatient trial suggests that monoclonal antibodies such as
casirivimab and imdevimab have the greatest benefit when given early after diagnosis and
in patients who are seronegative and/or who have high viral load. The criteria for ‘high-risk’
patients are described in the Fact Sheet for Healthcare Providers. In the U.S., casirivimab
and imdevimab are not authorized for use in patients who are hospitalized due to COVID19 or require oxygen therapy, or for people currently using chronic oxygen therapy becauseof an underlying comorbidity who require an increase in baseline oxygen flow rate due to COVID-19.