.Attribute Medicine, Published online: 13 September 2024 doi:10.1038/ s41591-024-03261-7In the non-randomized period 3b/4 DESTINY-Breast12 research study, trastuzumab deruxtecan (T-DXd) treatment of people with HER2+ innovative breast cancer and active or steady human brain metastases presented consistent intracranial activity as well as systemic efficacy of T-DXd.