Our in vivo experiments confirmed the interest of co-targeting EGFR and HER3 in pancreatic cancer, in line with previous reports on the anti-EGFR/HER3 BsAb scDb hu225x3-43-Fc in breast and head and neck cancers (52), duligotuzumab (MEHD7945A) (40, 77) in colorectal cancer, and SI-B001 (41) in locally advanced and metastatic tumors. This evidence concerns the gene ERBB3 and head and neck cancer.