The Food and Drug Administration has granted emergency use authorization (EUA) to casirivimab and imdevimab (REGN-COV2) for the treatment of mild to moderate coronavirus disease 2019 (COVID-19). The authorization applies to adults and pediatric patients 12 years of age and older weighing at least 40kg with positive results of direct severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral testing who are at high risk for progressing to severe COVID-19.

The investigational treatment from Regeneron consists of 2 potent, virus-neutralizing antibodies that bind noncompetitively to the receptor binding domain of the SARS-CoV-2 spike protein, thereby blocking its interaction with the host cell. In a clinical trial involving 799 nonhospitalized patients with mild to moderate COVID-19, casirivimab and imdevimab were found to reduce both viral load and COVID-19 related medical visits within 28 days after treatment. Among those at high risk for disease progression, hospitalizations and emergency room visits occurred in 3% of patients in the casirivimab and imdevimab arm vs 9% of those in the placebo arm. 

Commenting on the study results, George D. Yancopoulos, MD, PhD, President and Chief Scientific Officer of Regeneron, said: “We are encouraged that no variants resistant to the cocktail were identified in the clinical trial analyses to date, which is consistent with our preclinical findings.”

A fact sheet provided to healthcare professionals outlines important information related to the use of casirivimab and imdevimab, which must be administered together by intravenous (IV) infusion in a setting equipped to handle potentially severe infusion reactions, such as anaphylaxis. The single IV infusion should be given as soon as possible after positive viral test for SARS-CoV-2 and within 10 days of symptom onset. 

As for supply, Regeneron expects to have approximately 80,000 doses by the end of November, 200,000 by the first week of January and 300,000 by the end of January 2021. Amerisource Bergen will handle the distribution of the antibody cocktail, which will be directed by the US government as part of Operation Warp Speed. 

Casirivimab and imdevimab are not authorized for use in patients who are hospitalized or require oxygen therapy due to COVID-19. The therapy is currently being assessed in trials involving hospitalized COVID-19 patients, as well as for prevention of COVID-19 in household contacts of infected individuals.

For more information call (844) 734-6643 or visit


  1. Coronavirus (COVID-19) update: FDA authorizes monoclonal antibodies for treatment of COVID-19. [press release]. November 21, 2020.
  2. Regeneron’s REGEN-COV2 is first antibody cocktail for COVID-19 to receive FDA emergency use authorization. [press release]. November 21, 2020.