.Nature Medicine, Released online: 13 September 2024 doi:10.1038/ s41591-024-03261-7In the non-randomized stage 3b/4 DESTINY-Breast12 study, trastuzumab deruxtecan (T-DXd) therapy of people with HER2+ state-of-the-art bosom cancer as well as energetic or stable brain metastases presented constant intracranial activity as well as systemic effectiveness of T-DXd.