Casirivimab and imdevimab as investigational monoclonal antibodies for COVID-19 patients – review of the literature

Casirivimab and imdevimab (REGN-COV-2) are investigational monoclonal antibodies approved in November 2020 by the Food and Drug Administration for emergency use in mild and moderate COVID-19. These two noncompeting human IgG1 monoclonal antibodies can target the receptor-binding domain of the spike protein of SARSCoV-2, prevent its entry into human cells, and reduce viral load. The antibodies can be administered intravenously for mild-to-moderate COVID-19 patients who do not require hospitalization and supplemental oxygen. The purpose of the study is to review the latest available data on COVID-19 treatment using casirivimab and imdevimab. According to recent preclinical studies, the antibody cocktail presents optimal antiviral strength and has the potential to minimize the chances of the virus escaping. It was shown in animal studies that the cocktail reduces the pathological consequences caused by viruses, decreases the number of viruses in the respiratory system, and reduces lung titers and pneumonia symptoms. Casirivimab and imdevimab as a cocktail also prevents the rapid appearance of treatment-resistant mutants. In the clinical trial, REGN-COV-2 decreased viral load, particularly in patients with a non-initiated immune response (serum antibody-negative) and with high viral load at baseline. The adverse effects were comparable in the combined REGN-COV2 dose groups (2.4 g and 8.0 g), as well as in the placebo group. The cocktail caused few and mainly low-grade toxic effects. Casirivimab and imdevimab seem to be effective and safe antiviral therapy for nonhospitalized patients with COVID-19. Further observations and research are extremely necessary to assess the efficacy, security and indications in a wider group of patients.