.Attributes Medicine, Released online: 13 September 2024 doi:10.1038/ s41591-024-03261-7In the non-randomized period 3b/4 DESTINY-Breast12 study, trastuzumab deruxtecan (T-DXd) therapy of people with HER2+ sophisticated bosom cancer cells as well as energetic or steady human brain metastases revealed constant intracranial activity and wide spread efficiency of T-DXd.