Specifically, the DESTINY-Breast06 trial reported significantly longer progression-free survival with T-DXd (13.2 months) versus chemotherapy (8.1 months) in patients with HER2-low (IHC 1+ or IHC 2 + /ISH-) or HER2-ultralow (IHC 0 with membrane staining) breast cancer resulting in its FDA approval for this molecularly defined patient population51. Here, ERBB2 is linked to breast cancer.