Here we report the case of a 54-year-old post-menopausal woman with relapsed triple-negative breast cancer in the skin and lymph nodes with a sustained response to T-DXd after progression on SG…. This case shows that T-DXd following SG can potentially have efficacy in patients with HER2-low metastatic breast cancer, though formal studies are needed to quantify the response rate and if the reverse sequence (T-DXd → SG) also has efficacy.