The antibody cocktail, formerly known as REGN-COV2, is authorized for use in adults and pediatric patients over 12 years of age and weighing at least 88 lb with positive results of direct SARS-CoV-2 viral testing.

The EUA was issued based on evidence from an ongoing phase II/III double-blind, placebo-controlled clinical trial in 799 nonhospitalized adults with mild to moderate COVID-19 symptoms. Patients either received an IV infusion of 2,400 mg (1,200 mg each), 8,000 mg (4,000 mg each), or placebo.

The trial met the primary end point of viral load reduction in treated patients within seven days. But the treatment also reduced COVID-19-related hospitalizations or emergency room visits within 28 days after the treatment when compared to the placebo.

The FDA issued the EUA based on available scientific evidence and determined that it is reasonable to believe that casirivimab and imdevimab administered together may be effective in treating patients with mild or moderate COVID-19. The agency will continue to evaluate the safety and effectiveness of the investigational therapy.

Monoclonal antibodies are made to mimic the immune system's ability to fight off harmful pathogens

Casirivimab and imdevimab specifically target the spike protein of SARS-CoV-2 and are designed to block the virus's attachment and entry into human cells. Regeneron discovered the mAbs on its Velocimmune platforms.

Regeneron rapidly scaled up production of the antibody cocktail with support from the U.S. Biomedical Advanced Research and Development Authority (BARDA). Regeneron expects to have treatment doses ready for approximately 80,000 patients by the end of November, approximately 200,000 patients by the first week of January, and approximately 300,000 patients in total by the end of January 2021.