FDA Authorizes Regeneron's COVID-19 Monoclonal Antibody Treatment

Carolyn Crist


November 23, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

The FDA issued an emergency use authorization to Regeneron Pharmaceuticals for its monoclonal antibodies — casirivimab and imbdevimab — to be administered together to treat mild-to-moderate COVID-19 in adults and kids over age 12.

The treatment should be given to patients who have a positive coronavirus test and face a high risk for progressing to severe COVID-19, including those who are 65 and older or have certain chronic medical conditions.

"Authorizing these monoclonal antibody therapies may help outpatients avoid hospitalization and alleviate the burden on our health care system," Stephen Hahn, MD, commissioner of the FDA, said in a statement.

Casirivimab and imdevimab must be given together through an intravenous infusion. The lab-made proteins mimic the immune system and specifically target the spike protein on SARS-CoV-2, blocking the virus from entering human cells.

In a clinical trial of nearly 800 patients, the antibody treatment was shown to reduce COVID-19 hospitalizations and emergency room visits in patients who had a high risk of disease progression. Within 28 days of treatment, 3% of people who took the treatment were hospitalized, as compared with 9% of people who received the placebo.

The antibody combination is not authorized for patients who are hospitalized for COVID-19 or require oxygen. Clinical trials have not shown benefits for using the treatment in hospitalized patients, and in fact, may lead to worse outcomes for those who need oxygen or ventilation, the FDA said. Possible side effects include a sudden allergic reaction called anaphylaxis and infusion-related reactions, fever, chills, hives, itching, and skin reddening or blotching.

The experimental therapy was given to President Donald Trump when he contracted the coronavirus in October, according to CNBC. The FDA will continue to evaluate the safety and the results of the therapy for full approval.

Earlier this month, the FDA also authorized Eli Lilly's antibody treatment — called bamlanivimab — for people who have COVID-19 and face high risks for developing a severe form of the disease.

"The emergency authorization of these monoclonal antibodies administered together offers health care providers another tool in combating the pandemic," Patrizia Cavazzoni, MD, acting director of the FDA's Center for Drug Evaluation and Research, said in a statement.


FDA, "FDA Authorizes Monoclonal Antibodies for Treatment of COVID-19."

CNBC, "FDA authorizes Regeneron's Covid treatment, taken by Trump, for emergency use."