Early phase trials showed promising response rates in ovarian epithelial cancer (100%), human epidermal growth factor receptor 2 (HER2)-positive sarcoma (67%), epidermal growth factor receptor (EGFR)-positive biliary tract cancer (65%), advanced gastric/pancreatic cancer (82%), hepatocellular carcinoma (67%), and colorectal cancer (70%). The gene discussed is ERBB2; the disease is biliary tract neoplasm.