This commentary focuses on the DESTINY-Breast12 study, published in Nature Medicine on 13 September 2024, which evaluates the efficacy of Trastuzumab deruxtecan (T-DXd) in treating HER2-positive advanced breast cancer, including those with brain metastases. We emphasize the broadened clinical potential of T-DXd in treating brain metastases from tumors originally classified as HER2-null or HER2-low, extending beyond its current use for breast cancer. This expanded application of T-DXd could provide new hope to patients dealing with challenging brain metastases, addressing an urgent need for effective treatment options.