The FDA expanded the label for AstraZeneca and Daiichi Sankyo’s antibody‑drug conjugate Enhertu, clearing its use in combination with pertuzumab as a first‑line therapy for unresectable or metastatic HER2‑positive breast cancer. Regulators based the decision on pivotal trial data showing a substantial extension of progression‑free survival compared with prior standards of care. The label expansion positions Enhertu to supplant long‑standing regimens in first‑line HER2 disease and tightens competition among HER2‑targeted therapies. Roche also received diagnostic label updates to identify patients eligible for Enhertu across the spectrum of HER2 expression, enabling broader patient selection with companion assays. Clinicians welcomed the option but noted real‑world adoption will hinge on diagnostic rollout, safety management, and payer access.