Abstract 5315: Bispecific antibody discovery platform for IND enabling studies: Case study of HER-2/NKG2D bispecific antibody
Authors: Ratcliffe Laura , Pooley Rachel , Carr Katherine , Janbazacyabar Hamed , Lopez David Cobeta , Bruce Deborah , Martin Sarah L. , Benson Matthew , White Jonathan , Quist Benita , Vermond Sophie , Moiset Gemma , Hill Sophie , Feldman Renny , Wan Paul , Oswald Eva , Verkaar Folkert , Aspinall-O'Dea Mark , Schueler Julia , Jayanth Namrata 
Published: March 2024

Abstract
There has been a surge in the number of therapeutic antibody modalities primarily attributable to the increasing array of antibody engineering platforms. Among these, the emergent class of bispecific antibodies has exhibited remarkable potential compared to conventional monoclonal antibodies, marked by their targeting precision, expanded therapeutic scope, and personalized medicine prospects. Presently, eight bispecific antibodies are approved, with over 100 in varying clinical trial phases. Using a bispecific targeting HER-2 and NKG2D, we outline a comprehensive end-to-end platform for bispecific antibody discovery and characterization, designed to facilitate the progression of novel bispecific antibodies through the antibody discovery pipeline. To secure the most optimal binders tailored to specific targets, our methodology capitalizes on an extensive repertoire of phage display libraries. This strategy is instrumental in the identification of antibody candidates with exceptional binding affinity, broad cross-species compatibility, and enhanced drug-like properties. From the anti-HER2 chimeric antigen receptor ML39 and anti-NKG2D Fab KYK2.0, we synthesized four distinct bispecific formats by fusing single-chain variable fragments (scFv) to immunoglobulin G (IgG) molecules. These formats varied in terms of valency and scFv positioning, allowing us to assess their impact on antibody expression, binding kinetics, and functional efficacy. Subsequently, the bispecific antibodies underwent comprehensive in vitro efficacy and safety characterization, employing multiple innovative technologies. Utilizing a distinctive label-free approach with the xCELLigence system, we elucidated the kinetics of immune cell-mediated target cell killing upon antigen-antibody complex recognition in specific cancer cells. Safety assessments, with a focus on on-target/off-tumor effects, were conducted using the Retrogenix platform. Furthermore, cytokine profiling was utilized to evaluate potential risks associated with enhanced cytokine levels, reinforcing the specificity and safety profile of the bispecific antibody. Finally, pertinent in vivo models, including peripheral blood mononuclear cells (PBMC) and immune cell transfer models, facilitated the translation of preclinical bispecific antibody evaluations into clinically relevant contexts. This comprehensive platform for bispecific antibody discovery and functional characterization serves as a robust foundation for supporting Investigational New Drug (IND) applications, thus facilitating the transition of novel bispecific antibodies from the pre-clinical to the clinical phase of the drug discovery process.
Citation Format: Laura Ratcliffe, Rachel Pooley, Katherine Carr, Hamed Janbazacyabar, David Cobeta Lopez, Deborah Bruce, Sarah L. Martin, Matthew Benson, Jonathan White, Benita Quist, Sophie Vermond, Gemma Moiset, Sophie Hill, Renny Feldman, Paul Wan, Eva Oswald, Folkert Verkaar, Mark Aspinall-O'Dea, Julia Schueler, Namrata Jayanth. Bispecific antibody discovery platform for IND enabling studies: Case study of HER-2/NKG2D bispecific antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5315.