Based on the results of MOUNTAINEER (NCT03043313) in HER2-positive mCRC, the ongoing dose escalation and expansion phase Ib/II SGNTUC-024 (NCT04430738) trial evaluates the efficacy of tucatinib (HER2 inhibitor) plus trastuzumab plus FOLFOX in patients with HER2-positive gastric, oesophageal, and GEJ adenocarcinoma, cholangiocarcinoma, gallbladder carcinoma, and CRC.49 The gene discussed is ERBB2; the disease is cholangiocarcinoma.