FDA Approves Monoclonal Antibody Therapies for COVID-19

The FDA has authorized intravenous (IV) casirivimab and imdevimab to be administered together for the treatment of patients aged 12 and older with mild to moderate COVID-19 who are at high risk of progressing to severe disease, including those over the age of 65 and with chronic medical conditions.

The agency’s decision was based on data from a phase II/III trial, in which the monoclonal antibody cocktail was shown to reduce hospitalizations or emergency room visits within 28 days of treatment compared with placebo. Within 3 days of a positive COVID-19 test, 533 patients received either 2,400 or 8,000 mg of IV casirivimab and imdevimab, while 266 were treated with placebo. For patients with COVID-19 at high risk of disease progression, an average of 3% of patients who received the monoclonal antibody treatment were hospitalized or visited the emergency room, compared with 9% of patients who received placebo.

“Authorizing these monoclonal antibody therapies may help outpatients avoid hospitalization and alleviate the burden on our health care system,” FDA Commissioner Stephen Hahn, MD, said.

In addition, the study found a greater reduction in viral load for patients treated with the monoclonal antibody cocktail compared with placebo on day 7. Reductions in viral load, hospitalizations, and emergency room visits were similar in patients who received 2,400 and 8,000 mg doses.

Adverse events of casirivimab and imdevimab include anaphylaxis and infusion-related reactions, fever, chills, hives, itching, and redness. The combination is not authorized for patients who are hospitalized for COVID-19 or who require oxygen therapy.

Sources: FDA press release, November 21, 2020; MedPage Today, November 23, 2020.