Trastuzumab combined with irinotecan in patients with HER2-positive metastatic colorectal cancer: A phase II single-arm study and exploratory biomarker analysis

Purpose The human epidermal growth factor receptor 2 (HER2) is an established therapeutic target for various kinds of solid tumors. HER2 amplification occurs in approximately 1% to 6% of colorectal cancer. In this study, we aimed to assess the efficacy and safety of trastuzumab in combination with chemotherapy in HER2-positive mCRC.