Weissenfels

Researchers are observing the real-world effects and patient experiences of trastuzumab deruxtecan T-DXd treatment in adults with HER2-positive, HER2-low, or HER2-ultralow unresectable or metastatic breast cancer. This prospective, non-interventional study takes place in multiple centers in Germany and aims to collect patient-reported outcomes along with safety and efficacy data during routine clinical practice. Approximately 800 patients will be enrolled, divided evenly between HER2-positive and HER2-lowultralow cohorts. Participants will receive T-DXd treatment as prescribed by their doctors according to the approved product guidelines SmPC. Treatment and visit schedules are determined by the treating physician and are not fixed by the study protocol. Patients will also be informed about using a digital healthcare application DiGA during the study. The study includes two cohorts based on HER2 status, both receiving T-DXd in routine care. During the study, participants will be followed to measure the time until their next treatment or death, assessed for up to 60 months from the first T-DXd dose. Quality of life will be evaluated using questionnaires at six months after baseline. Patient safety and treatment effects will be monitored through data collected in routine clinical visits. The total participation period may extend up to eight years, allowing for long-term observation of treatment outcomes in real-world settings.