ERBB2 and breast cancer: Based on high intracranial response rates against parenchymal BMs seen in several studies, including the TUXEDO-1 (NCT04752059), DEBBRAH (NCT04420598) and DESTINY-Breast12 (NCT04739761) trials22–25, the HER2-targeting ADC trastuzumab deruxtecan (T-DXd) is recommended for therapy of patients with active BMs of HER2-positive breast cancer in contemporary clinical practice guidelines26.