Datopotamab deruxtecan (DATROWAY) is a trophoblast cell surface antigen 2 (TROP2)-directed antibody-drug conjugate being developed by Daiichi Sankyo and AstraZeneca for the treatment of solid tumours. On 27 December 2024, datopotamab deruxtecan was approved in Japan for the treatment of adult patients with hormone receptor (HR) positive, human epidermal growth factor receptor 2 (HER2) negative unresectable or recurrent breast cancer after prior chemotherapy. The drug has since been approved on 17 January 2025 in the USA for the treatment of adult patients with unresectable or metastatic HR positive, HER2 negative breast cancer who have received prior endocrine-based therapy and chemotherapy for unresectable or metastatic disease. Datopotamab deruxtecan has also been approved in the EU for the treatment of adult patients with unresectable or metastatic HR positive, HER2 negative breast cancer who have received endocrine therapy and at least one line of chemotherapy in the advanced setting. Regulatory review of datopotamab deruxtecan in breast cancer is underway in Canada and China. This article summarizes the milestones in the development of datopotamab deruxtecan leading to this first approval for the treatment of HR positive, HER2 negative breast cancer.