Beamion BCGC-1: phase Ib/II trial of zongertinib for advanced HER2-positive breast or gastroesophageal cancers

Background Overexpression and/or amplification of human epidermal growth factor receptor 2 (HER2) is a recognized oncogenic driver in metastatic breast cancer (mBC) and metastatic gastric, gastroesophageal junction, or esophageal adenocarcinomas (mGEAC). Although HER2-directed monoclonal antibodies, antibody – drug conjugates (ADCs), and tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of HER2-positive tumors, additional combination regimens and/or novel agents are needed to expand sequential therapy options and improve patient outcomes – particularly following treatment with trastuzumab deruxtecan (T-DXd). Zongertinib is a novel, irreversible, HER2-selective TKI that spares EGFR.