In the Phase III TROPION-Breast01 trial (NCT05104866), the efficacy and safety of Dato-DXd were compared with investigator’s choice of standard single-agent chemotherapy (including eribulin, vinorelbine, gemcitabine, or capecitabine) in patients with HR+/HER2- breast cancer who had previously received one or two lines of systemic chemotherapy and were either ineligible for surgery or had metastatic disease (61). The gene discussed is HR; the disease is breast cancer.