DESTINY Breast Respond HER2-(Ultra)Low Europe

This non-interventional study will investigate the effectiveness of T-DXd, the demographic and clinical characteristics of the patients, treatment patterns, tolerability, management of adverse drug reactions (ADRs), and patient experience of T-DXd in patients with HER2-low and HER2-(ultra)low unresectable and/or metastatic breast cancer. Patients will be treated according to the proposed indication statement in the Summary of Product Characteristics (SmPC). No drug product will be administered as part of this study. Data on conventional chemotherapy (i.e., including but not limited to capecitabine, eribulin, gemcitabine, paclitaxel and nab-paclitaxel) will also be collected in a disease registry part of the study. For Study Group 2, only baseline data will be collected for patients treated with conventional chemotherapy.