Definition

A combination of two monoclonal antibodies, casirivimab and imdevimab, directed against the spike protein (SP) of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), that can potentially be used for immunization against COVID-19. Upon administration, casirivimab and imdevimab specifically target and bind to non-overlapping regions of the receptor-binding domain (RBD) of SP, thereby blocking viral attachment and entry into human cells and may thereby neutralize SARS-CoV-2. This may slow the progression of the disease and accelerate recovery, and may potentially provide temporary protection against infection with SARS-CoV-2. Binding to two distinct regions of the RBD of SP may decrease the potential for virus escape mutants that occur upon treatment with a single SARS-CoV-2 antibody, and may provide enhanced protection against loss of efficacy.