In the DESTINY-Breast01 trial of heavily pretreated patients with unresectable or metastatic HER2+ BC, T-DXd provided an objective response rate (ORR) of 62%, an 18.2-month (95% confidence interval [CI], 15.0 months to not evaluable) duration of response, and a small (1.6%) rate of further disease progression (7). Here, ERBB2 is linked to breast cancer.