Efficacy of Antiviral Agents against Omicron Subvariants BQ.1.1 and XBB

This correspondence assesses the effectiveness of monoclonal antibodies and antiviral drugs against SARS-CoV-2 Omicron subvariants BQ.1.1 and XBB. Researchers found that all tested monoclonal antibodies—including imdevimab, casirivimab, tixagevimab, cilgavimab, sotrovimab (S309), and bebtelovimab—failed to neutralize either subvariant, even at high concentrations. The subvariants exhibited additional mutations in the receptor-binding domain, contributing to immune evasion. Conversely, small-molecule antivirals (remdesivir, molnupiravir, and nirmatrelvir) maintained similar efficacy across ancestral and Omicron variants, with IC₅₀ values within therapeutic ranges. The study highlights the urgent need for new antibody therapies as variants evolve.

This correspondence assesses the effectiveness of monoclonal antibodies and antiviral drugs against SARS-CoV-2 Omicron subvariants BQ.1.1 and XBB. Researchers found that all tested monoclonal antibodies—including imdevimab, casirivimab, tixagevimab, cilgavimab, sotrovimab (S309), and bebtelovimab—failed to neutralize either subvariant, even at high concentrations. The subvariants exhibited additional mutations in the receptor-binding domain, contributing to immune evasion. Conversely, small-molecule antivirals (remdesivir, molnupiravir, and nirmatrelvir) maintained similar efficacy across ancestral and Omicron variants, with IC₅₀ values within therapeutic ranges. The study highlights the urgent need for new antibody therapies as variants evolve.