This is an immunoglobulin G (IgG) bispecific antibody targeting both the epidermal growth factor receptor (EGFR, HER1, ErbB1) and the epidermal growth factor receptor 3 (HER3, ErbB3), with potential antineoplastic activity. It simultaneously targets and binds to EGFR and HER3 expressed on cancer cells, thereby preventing receptor phosphorylation. This prevents the activation of both EGFR- and HER3-mediated signaling pathways and results in the inhibition of tumor cell proliferation. EGFR and HER3, both upregulated and/or mutated in a variety of tumor cell types, play key roles in tumor cell proliferation.