This is a multi-center, observational prospective study that will characterize the demographic and clinical characteristics, treatment patterns, effectiveness, tolerability and its management, and patient experience of Trastuzumab Deruxtecan (T-DXd) in a real-world setting. This study is planned to be conducted in several countries and aims to enroll approximately 750 patients eligible patients with HER2+ unresectable and/or metastatic breast cancer (mBC) who has received a prior anti HER2 based regimen in the metastatic setting or in the neoadjuvant or adjuvant setting and has developed disease recurrence during or within 6 months of completing therapy. Approximately 250 eligible patients with HER2-low unresectable and/or mBC who have received a prior chemotherapy in the metastatic setting or developed disease recurrence during or within 6 months of completing adjuvant chemotherapy will be enrolled into the study in North America only.~The planned duration of patient recruitment is approximately 18 months for HER2+ and approximately 12 months for HER2 low.
This study will collect real-world clinical and patient reported outcomes (PRO) and diary data from eligible patients with documented Human Epidermal Growth Factor Receptor 2 (HER2+) [globally] or HER2-low [North America only] in routine clinical practice.