These results led to the DESTINY-Breast04 phase III, randomised, multicentre trial, comparing the efficacy and safety of T-DXd 5.4 mg/kg versus physician’s choice chemotherapy (capecitabine, eribulin, gemcitabine, paclitaxel or nab-paclitaxel) in patients with HER2-low, unresectable and/or MBC....