The HER2-PREDICT study, sponsored by SOLTI Breast Cancer Research Group in collaboration with Daiichi Sankyo, aims to enhance understanding of the predictive biomarkers associated with Trastuzumab Deruxtecan (T-DXd; DS-8201a) in metastatic cancer. As the market for HER2-targeted therapies continues to expand, particularly in breast cancer, this study could provide critical insights that may influence treatment protocols and patient stratification. The data generated may also support the development of companion diagnostics, enhancing the commercial viability of T-DXd and potentially leading to increased market share in the competitive landscape of oncology therapeutics. The study's observational nature allows for flexibility in patient enrollment and data collection, which could facilitate quicker insights into treatment efficacy and safety profiles.