In addition to the indications for metastatic breast cancer, T-DXd is approved in the United States for locally advanced/metastatic HER2-positive gastric cancer, based on the positive results of the DESTINY-Gastric01 and DESTINY-Gastric02 trials [9,10]; for metastatic HER2-positive nonsmall cell lung cancer (NSCLC), based on the DESTINY-Lung01 and DESTINY-Lung02 trials [11,12,13]; and is under investigation for various additional tumor types, including colorectal and other cancers [14,15]. This evidence concerns the gene ERBB2 and breast carcinoma.