In a November 21st release, the U.S. Food and Drug Administration approved administration of a combination of two monoclonal antibodies developed by Regeneron Pharmaceuticals.  The combination comprising casirivimab and imdevimab targets the receptor-binding site for the spike protein of SARS-CoV-2 virus responsible for COVID-19.  This combination of monoclonal therapeutic agents is now authorized for non-hospitalized patients over twelve years in age.  It is anticipated that Regeneron will be able to supply a sufficient quantity of the two compounds to treat 80,000 patients during early December and up to 300,000 by the end of January 2021.  Roche Pharmaceuticals will be responsible for production of the Regeneron monoclonal antibodies.

According to the FDA release, a structured clinical trial was carried out at a number of participating centers involving 799 non-hospitalized adults with mild to moderate COVID-19 symptoms.  Of this cohort, 266 received a single intravenous infusion of 2,400 milligrams of the combination, 267 received 8,000 mg of the combination and 266 received a placebo.  All participants were confirmed positive applying an approved SARS-CoV-2 viral assay.

For patients at high risk for disease progression, hospitalizations and ER care, three percent of the recipients of the combination required hospitalization compared to nine percent in the placebo group.  There was no difference in viral load or frequency of ER visits between subjects treated with the monoclonal antibody combination and the controls.

The emergency use authorization extended to Regeneron Pharmaceuticals includes dosing instructions, an obligation to record potential side effects and drug interactions and the statutory restraints associated with Emergency Use Authorization.