Understanding the role of cross-arm binding efficiency in the activity of monoclonal and multispecific therapeutic antibodies

• Published in: Methods (San Diego, Calif.) Calif.), 2014-01, Vol.65 (1), p.95-104
• Main Authors: Harms, Brian D., Kearns, Jeffrey D., Iadevaia, Sergio, Lugovskoy, Alexey A.
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Bispecific - chemistry; Antibodies, Bispecific - pharmacology; Antibodies, Monoclonal - chemistry; Antibodies, Monoclonal - pharmacology; Antibody Specificity; Avidity; Bispecific antibody; Cell Line; Computational modeling; Cross-arm binding; Humans; Immunoglobulin; Immunoglobulin G - chemistry; Inhibitory Concentration 50; Multispecific antibodies; Protein Binding; Protein Engineering; Proto-Oncogene Proteins c-akt - antagonists & inhibitors; Proto-Oncogene Proteins c-akt - metabolism; Receptor, ErbB-2 - antagonists & inhibitors; Receptor, ErbB-2 - immunology; Receptor, ErbB-2 - metabolism; Receptor, ErbB-3 - antagonists & inhibitors; Receptor, ErbB-3 - immunology; Receptor, ErbB-3 - metabolism; Receptor, IGF Type 1 - antagonists & inhibitors; Receptor, IGF Type 1 - metabolism
• ISSN: 1046-2023; 1095-9130
• DOI: 10.1016/j.ymeth.2013.07.017

•Simultaneous engagement of functional arms in monoclonal and multispecific antibodies is essential component of their activity.•Optimization of cross-arm binding efficiency increases the potency of therapeutic antibodies.•Computational modeling prioritizes design approaches for increasing cross-arm binding. Antibodies are essential components of the adaptive immune system that provide protection from extracellular pathogens and aberrant cells in the host. Immunoglobulins G, which have been adapted for therapeutic use due to their exquisite specificity of target recognition, are bivalent homodimers composed of two antigen binding Fab arms and an immune cell recruiting Fc module. In recent years significant progress has been made in optimizing properties of both Fab and Fc components to derive antibodies with improved affinity, stability, and effector function. However, systematic analyses of the efficiency with which antibodies crosslink their targets have lagged, despite the well-recognized importance of this cross-arm binding for optimal antigen engagement. Such an understanding is particularly relevant given the variety of next-generation multispecific antibody scaffolds under development. In this manuscript we attempt to fill this gap by presenting a framework for analysis and optimization of antibody cross-arm engagement. We illustrate the power of this integrated approach by presenting case studies for rational multispecific antibody design based on quantitative assessment of the interplay between antibody valency, target expression, and cross-arm binding efficiency. We conclude that optimal design parameters for cross-arm binding strongly depend on the biological context of the disease, and that cross-arm binding efficiency needs to be considered for successful application of multispecific antibodies.