ERBB2 and breast cancer: The DESTINY-Breast06 trial (NCT04494425), which is designed to evaluate the efficacy, safety, and tolerability of T-DXd in metastatic HER2-low/HR-positive BC patients whose disease has progressed on endocrine therapy in the metastatic setting, is actively recruiting BC patients with HER2-low BCs and HER2 IHC expression of > 0 and < 1+.