Furthermore, based on the results from the DESTINY-Breast06 trial, T-DXd is now approved for the treatment of patients with HR-positive, HER2-low, or HER2-ultralow advanced breast cancer, as determined by a locally or regionally approved test, that has progressed on one or more endocrine therapies in the metastatic setting [10]. This evidence concerns the gene ERBB2 and breast carcinoma.