SARS-CoV-2 variant evasion of monoclonal antibodies based on in vitro studies

Monoclonal antibodies (mAbs) offer a treatment option for individuals with severe COVID-19 and are especially important in high-risk individuals where vaccination is not an option. Given the importance of understanding the evolution of resistance to mAbs by SARS-CoV-2, we reviewed the available in vitro neutralization data for mAbs against live variants and viral constructs containing spike mutations of interest. Unfortunately, evasion of mAb-induced protection is being reported with new SARS-CoV-2 variants. The magnitude of neutralization reduction varied greatly among mAb-variant pairs. For example, sotrovimab retained its neutralization capacity against Omicron BA.1 but showed reduced efficacy against BA.2, BA.4 and BA.5, and BA.2.12.1. At present, only bebtelovimab has been reported to retain its efficacy against all SARS-CoV-2 variants considered here. Resistance to mAb neutralization was dominated by the action of epitope single amino acid substitutions in the spike protein. Although not all observed epitope mutations result in increased mAb evasion, amino acid substitutions at non-epitope positions and combinations of mutations also contribute to evasion of neutralization. This Review highlights the implications for the rational design of viral genomic surveillance and factors to consider for the development of novel mAb therapies. In this Review, Carabelli, Robertson and colleagues explore data on the neutralization of globally circulating variants of concern by monoclonal antibodies (mAbs) and discuss how knowledge of the dynamics of viral evasion of mAbs can contribute to viral surveillance and the development of novel mAb treatments, as well as inform predictions of resistance that may arise in the future.

Automated summary

Monoclonal antibodies (mAbs) are an important treatment option for severe COVID-19, but the emergence of new SARS-CoV-2 variants has led to evasion of mAb-induced protection. Spike protein amino acid substitutions, both at epitope and non-epitope positions, play a role in resistance to mAb neutralization. Understanding the dynamics of viral evasion can inform surveillance and the development of novel mAb therapies.