.Attributes Medicine, Released online: 13 September 2024 doi:10.1038/ s41591-024-03261-7In the non-randomized phase 3b/4 DESTINY-Breast12 research, trastuzumab deruxtecan (T-DXd) treatment of people along with HER2+ advanced breast cancer cells as well as energetic or steady human brain metastases revealed constant intracranial activity and systemic efficacy of T-DXd.