Engineering a Trispecific EGFR × c-MET × VEGF Antibody with Multiple Mechanisms of Action for Antitumor Activity in Gastrointestinal Cancer Models

Background: A leading cause of cancer-related mortality worldwide, gastrointestinal (GI) cancers are often recalcitrant to single agent therapies. Dysregulations of the EGFR, cMET, and VEGF pathways are frequently observed together in these malignancies, making simultaneous multi-targeted therapy a promising strategy. Objectives: TAVO412, a trispecific antibody against EGFR, cMET, and VEGFA, employed complementary mechanisms of action to inhibit multiple GI cancer cell lines. Methods/Results: TAVO412 effectively suppressed phosphorylation of the targeted receptors, thereby inhibiting cancer cell proliferation in vitro. The antibody, engineered with enhanced Fc function, displayed strong antibody-dependent cytotoxicity, antibody-dependent cellular phagocytosis, and complement-dependent cytotoxicity. In vivo studies demonstrated that the anti-VEGFA domain design was central to drug efficacy, with the non-cleavable linker format performing optimally, presumably due to tumor-localized VEGF binding. In a pancreatic cancer model, antitumor activity was primarily driven by anti-VEGF and anti-EGFR activities. Moreover, TAVO412 demonstrated superior antitumor activity compared to bevacizumab or amivantamab monotherapy, and was as effective as their combination in colorectal and esophageal cancer models. Conclusions: Collectively, these preclinical findings laid the groundwork for clinical trials of TAVO412 in patients with advanced gastrointestinal cancers expressing EGFR, cMET, and VEGF.