Trastuzumab deruxtecan (Enhertu®, Daiichi Sankyo Company, Limited, NJ, USA), an antibody-drug conjugate consisting of the anti-HER2 antibody bound to a cytotoxic topoisomerase I inhibitor [62], has recently been assessed for patients with locally advanced or metastatic HER-2 positive GC/GEJ adenocarcinoma who had received a prior trastuzumab regimen in the phase 2 DESTINY-Gastric01 study [63]. The gene discussed is ERBB2; the disease is gastric cancer.