Irinotecan Plus Anlotinib or Further in Combination With Penpulimab for Second-line Treatment of mCRC

This is an exploratory, non-controlled, multi-cohort, phase II small-sample clinical study designed to evaluate the clinical benefit of second-line treatment with anlotinib plus irinotecan or further in combination with a PD-1 monoclonal antibody (penpulimab) in patients with advanced colorectal cancer after first-line treatment failure. To explore the rationality of the combination of chemotherapy and targeted therapy and immunotherapy strategy and obtain relevant survival and safety data. The study will fully evaluate the efficacy, PFS, OS, safety and related biomarkers of the regimen.