ERBB2 and breast cancer: T-DXd is approved for unresectable or metastatic HER2-positive breast cancer based on the results of DESTINY-Breast 03, confirming significant PFS benefit (HR 0.28; P < 0.0001)[86], as well as for unresectable or metastatic HER2-low breast cancer based on DESTINY-Breast 04 showing both promising PFS (HR 0.50; P < 0.001) and OS (HR 0.64; P = 0.001) benefit[87].