Impact of Cell-surface Antigen Expression on Target Engagement and Function of an Epidermal Growth Factor Receptor × c-MET Bispecific Antibody

• Published in: The Journal of biological chemistry 2015-10, Vol.290 (41), p.24689-24704
• Main Authors: Jarantow, Stephen W., Bushey, Barbara S., Pardinas, Jose R., Boakye, Ken, Lacy, Eilyn R., Sanders, Renouard, Sepulveda, Manuel A., Moores, Sheri L., Chiu, Mark L.
• Format: Article
• Language: English
• Subjects: Antibodies, Bispecific - immunology; Antigens, Surface - chemistry; Antigens, Surface - genetics; Antigens, Surface - immunology; Antigens, Surface - metabolism; bispecific antibody; c-MET; cancer therapy; Cell Line, Tumor; cell-surface receptor; epidermal growth factor (EGF); epidermal growth factor receptor (EGFR); ErbB Receptors - chemistry; ErbB Receptors - genetics; ErbB Receptors - immunology; ErbB Receptors - metabolism; Gene Expression Regulation; hepatocyte growth factor/scatter factor (HGF/SF); Humans; Immunoglobulin Fab Fragments - immunology; Models, Molecular; Molecular Bases of Disease; Molecular Targeted Therapy; Mutation; Phosphorylation; Protein Multimerization; Protein Structure, Quaternary; Proto-Oncogene Proteins c-met - chemistry; Proto-Oncogene Proteins c-met - genetics; Proto-Oncogene Proteins c-met - immunology; Proto-Oncogene Proteins c-met - metabolism; quantitative flow cytometry; RNA, Messenger - genetics; RNA, Messenger - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M115.651653

The efficacy of engaging multiple drug targets using bispecific antibodies (BsAbs) is affected by the relative cell-surface protein levels of the respective targets. In this work, the receptor density values were correlated to the in vitro activity of a BsAb (JNJ-61186372) targeting epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (c-MET). Simultaneous binding of the BsAb to both receptors was confirmed in vitro. By using controlled Fab-arm exchange, a set of BsAbs targeting EGFR and c-MET was generated to establish an accurate receptor quantitation of a panel of lung and gastric cancer cell lines expressing heterogeneous levels of EGFR and c-MET. EGFR and c-MET receptor density levels were correlated to the respective gene expression levels as well as to the respective receptor phosphorylation inhibition values. We observed a bias in BsAb binding toward the more highly expressed of the two receptors, EGFR or c-MET, which resulted in the enhanced in vitro potency of JNJ-61186372 against the less highly expressed target. On the basis of these observations, we propose an avidity model of how JNJ-61186372 engages EGFR and c-MET with potentially broad implications for bispecific drug efficacy and design. Background: Cancer cells express surface antigens at different levels from normal cells. Results: Differences in EGFR and c-MET receptor density levels influenced the in vitro activity of an EGFR × c-MET bispecific antibody. Conclusion: Consideration of target expression levels is important for bispecific design. Significance: In addition to multiple pathway targeting, the unique avidity of bispecific antibodies contributes to their promise for cancer therapy.