Trastuzumab Rezetecan in Human Epidermal Growth Factor Receptor 2–Expressing Advanced Gastric Cancer or Gastroesophageal Junction Adenocarcinoma and Colorectal Cancer: A Multicenter, Open-Label, Phase I Trial

A multicenter, open-label phase I trial published in the Journal of Clinical Oncology evaluated trastuzumab rezetecan, a novel antibody-drug conjugate targeting HER2, in patients with HER2-expressing advanced gastric or gastroesophageal junction adenocarcinoma and colorectal cancer. The study assessed safety, pharmacokinetics, and preliminary efficacy of this new ADC across multiple dose levels. These early-phase results contribute to the growing landscape of HER2-directed therapies beyond breast cancer, expanding potential treatment options for gastrointestinal malignancies. The findings provide a foundation for further clinical development in later-phase trials.