Liposomal Irinotecan (II) Fractionated Dosing Combined With 5-FU/LV (FOLFIRInali-3) and Bevacizumab in Second-line Treatment of Advanced Colorectal Cancer: A Single-arm, Phase II Clinical Study

This is an investigator-initiated, prospective, multicenter, single-arm phase II clinical study. It aims to evaluate the efficacy and safety of fractionated liposomal irinotecan (II)-based combination chemotherapy (FOLFIRInali-3) plus bevacizumab (Bev) as second-line treatment for advanced colorectal cancer, with the primary endpoint being objective response rate (ORR). Prospective participants must undergo screening assessments within 28 days before randomization to determine eligibility. Eligible subjects will receive second-line treatment with the FOLFIRInali-3 plus bevacizumab (Bev) regimen as follows: 1. Liposomal irinotecan (II): 30 mg/m² IV on D1 and D3 2. Fluorouracil (5-FU): * 400 mg/m² IV bolus on D1 * Followed by 2400 mg/m² continuous IV infusion over 46-48 hours 3. Leucovorin (LV): 400 mg/m² IV infusion on D1 4. Bevacizumab: 5 mg/kg IV infusion on D1。 Treatment will be discontinued upon occurrence of any of the following: 1. Disease progression (radiologically confirmed) 2. Intolerable toxicity (unmanageable after dose modification) 3. Initiation of new antitumor therapy 4. Withdrawal of informed consent 5. Investigator's discretion (based on clinical judgment) Patients received regular and periodic reviews, with imaging evaluations every 6 weeks.