A Clinical Study of Pyrotinib in Patients With HER2-positive Advanced Colorectal Cancer

This study is an investigator-initiated, open-label, two-cohort phase II trial, assessing the objective response rate (ORR) of pyrotinib monotherapy (Cohort 1) or in combination with trastuzumab (Cohort 2), in HER2-positive advanced colorectal cancer. HER2 positivity is centrally established by immunohistochemistry (IHC) and silver in situ hybridization (SISH). To be HER2 eligible the original tumor, or the biopsied metastasis (whichever is last available), must be IHC 3+ or 2+ in more than 50% of cells, confirmed by SISH or fluorescence in situ hybridization (FISH) with a HER2:CEP17 ratio ≥ 2.0. For IHC a positive staining (3+) is defined as an intense membrane staining which can be circumferential, basolateral, or lateral of the tumor cells.