RC48-ADC Combined With Bevacizumab in HER2-positive Advanced Colorectal Cancer

This is a single-arm, non-randomized, single-center trial. Enroll 30 patients with HER2-expressed metastatic colorectal cancer and failure of standard therapy. Divide into 2 cohorts, including 10 patients with low HER2 expression (IHC 2+/FISH negative) and 20 patients with high HER2 expression (IHC 2+/FISH positive or IHC3+). Administer RC48-ADC intravenously in combination with bevacizumab 5mg/kg once every two weeks. Medication must be discontinued until disease progression, intolerable toxicity, informed consent is withdrawn, or investigator judgment is made. The primary endpoints is objective response rate (ORR), and secondary endpoints are progression-free survival (PFS), overall survival (OS), and adverse effects (AE).