Abstract LB213: Identification of DM004, a first-in-class anti-5T4/MET bispecific antibody-drug conjugate

Abstract

Abstract Aberrant MET signaling is frequently found in various types of solid tumors, and is correlated with oncogenic transformation, treatment resistance and poor prognosis. While MET remains an attractive therapeutic target, it is widely expressed on the surface of epithelial and endothelial cells, including normal tissues and tumors. To date, MET-targeting agents are associated with adverse clinical effects, including hypoalbuminemia, peripheral edema and pneumonitis, indicating that alternate treatments and/or modalities are needed. Intriguingly, MET antigen is commonly co-expressed with the oncofetal antigen 5T4 in various cancer types, including head and neck, lung and pancreatic cancer. While 5T4 is highly expressed on primary and metastatic cancers and is associated with adverse clinical outcomes in solid tumors, expression on normal adult tissues is very limited. Although several therapeutic agents targeting 5T4 antigen are currently being evaluated in human clinical studies, none have yet entered the market. To address these challenges, we hypothesized that targeting both MET and 5T4 with a bispecific antibody-drug conjugate (BsADC) could provide a more targeted therapeutic strategy to effectively eliminate tumor cells and reduce systemic toxicity. Here, we report that we have successfully generated two bispecific antibody candidates targeting both 5T4 and MET. The candidates were conjugated with monomethyl auristatin E (MMAE) via a protease-cleavable linker to generate DM004 BsADCs, i.e., Top1-MMAE and Top2-MMAE. In vitro, DM004 BsAbs demonstrated enhanced internalization in the NCI-H226 cell line compared to its parental monoclonal and monovalent anti-5T4 and anti-MET antibodies. In vivo, DM004 BsADCs exhibited robust anti-tumor activity in cell line-derived and patient-derived xenografts of gastric cancer and lung cancer, respectively. In particular, DM004 Top2-MMAE outperformed benchmark ADCs in lung BP0508 PDX models. In summary, we have identified a novel BsADC which may be a promising future treatment for cancers co-expressing 5T4 and MET. Citation Format: Zhenyan Han, Chengzhang Shang, Wenjuan Dai, Gao An, Ellen Zhang, Qingcong Lin, Yi Yang. Identification of DM004, a first-in-class anti-5T4/MET bispecific antibody-drug conjugate [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB213.