Abstract 5675: Discovery and development of an asymmetric IgG-like bispecific antibody targeting EGFR and c-MET, engineered through H-H and H-L chain charge-based heterodimerization

Abstract Background: Lung cancer remains the leading cause of cancer mortality and is the most commonly diagnosed cancer with an estimated 2.2 million cases per year. EGFR, a tyrosine kinase receptor, plays a central role in cellular proliferation, survival, differentiation, and migration. Gain-of-function somatic mutations of EGFR significantly drives disease progression. Small molecule tyrosine kinase inhibitors (TKIs), designed to inhibit EGFR signaling specific to these mutations (e.g., L858R and E19del etc.), have achieved excellent clinical outcomes. However, patients carrying TKI-insensitive mutations (e.g., E20ins) and/or those with disease progression after TKI treatment, by the upregulation of complementary signaling pathways (HGF/c-MET, etc.), remain an unmet medical need. Here, we report the discovery of a fully-human afucosylated anti-EGFR x cMET IgG-like bispecific antibody (PM1080). Methods: PM1080 was generated by introducing unique mutations to the CH1-CL domains of each binding arm to promote correct HC-LC pairing. KIH mutations were also introduced to each CH3 domain to support HC-HC heterodimerization and generate an IgG-like bispecific with one arm binding to EGFR and the other to cMET. PM1080 was expressed via a four-chain expression system in CHO cells carrying a fut8−/− knockout to generate afucosylated molecules with enhanced ADCC activity. Results: Through monovalent affinity measurements, PM1080 interacted with EGFR at single digit nanomolar affinity and at sub-nanomolar affinity to c-MET. PM1080 preferentially bound to EGFR/c-MET double-positive cells rather than EGFR single-positive cells. PM1080 blocked both EGF/EGFR and HGF/c-MET signals via physical blockade of the interaction between EGF/HGF to their corresponding receptors and induced EGFR/c-MET internalization and degradation from the cell surface. Through intricate engineering, PM1080 was expressed via a four-chain system and produced as an afucosylated antibody with significantly improved ADCC function. PM1080 induced potent anti-tumor efficacy against EGFR/c-MET-positive tumor cells as a single agent. Importantly, PM1080 induced anti-tumor activity regardless of EGFR mutations at the intracellular signaling domain, and thus may serve as a promising combinational agent to TKI therapies. As expected, synergistic anti-tumor activity was observed when PM1080 was combined with either 1st or 3rd generation TKIs in both in vitro and in vivo models. Conclusion: PM1080, a bispecific antibody targeting EGFR & c-MET was discovered for cancer treatment. PM1080 displayed potent anti-tumor efficacy either as a single agent or in combination with EGFR TKIs. Preclinical PK and toxicity studies have been conducted to support future first-in-human studies. Citation Format: Ping Wang, Weifeng Huang, Zhenting Zhao, Xiaoniu Miao, Shaogang Peng, Chao Wang, Yao Yan, Tiantian Dong, Andy Tsun, Yingda Xu, Xiaolin Liu, Luo Yi. Discovery and development of an asymmetric IgG-like bispecific antibody targeting EGFR and c-MET, engineered through H-H and H-L chain charge-based heterodimerization. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5675.