ERBB2 and gastroesophageal junction adenocarcinoma: For example, in the dose-expansion trial of trastuzumab deruxtecan, investigators identified doses for clinical use as 5.4 mg/kg q3w and 6.4 mg/kg q3w for HER2+ breast cancer and HER2+ gastric/gastroesophageal junction adenocarcinoma, respectively (Shitara et al., 2019; Tamura et al., 2019).