Serplulimab+Regorafenib +Hepatic Artery Bicarbonate Infusion in Patients With Colorectal Cancer and Liver Metastases

This is a single-center, single-arm, phase 2 trial. Enroll 30 patients with colorectal cancer and liver metastases and failure of standard therapy. Administer serplulimab intravenously(once every two weeks)in combination with regorafenib(from the first day to the 21th day) and hepatic artery bicarbonate infusion (once every four weeks). Medication must be discontinued until disease progression, intolerable toxicity, informed consent is withdrawn, or investigator judgment is made. The primary endpoint is objective response rate (ORR), and secondary endpoints are progression-free survival (PFS), overall survival (OS), and adverse effects (AE).