Inclusion Criteria:
* Age: 18-75 years old.
* Histologically or cytologically proven colon or rectum adenocarcinoma.
* Confirmed as unresectable metastatic disease through radiological examination.
* At least one measurable lesion (according to RECIST v1.1).
* First-line treatment with oxaliplatin-based therapy.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 \~ 2.
* The expected survival time ≥3 months.
* Subject has adequate biological parameters as demonstrated by the following: absolute neutrophil count (ANC) ≥1.5×10\^9/L, platelet count ≥100×10\^9/L, hemoglobin (Hgb) ≥90 g/L, white blood cell (WBC)≥3.0×10\^9/L.
* Adequate hepatic function as evidenced by total bilirubin ≤1.5 × upper limit of normal (ULN), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and alanine aminotransferase (ALT) ≤2.5 x ULN, ≤5 x ULN if liver metastases are present.
* Adequate renal function as evidenced by serum creatinine (Cr)≤1.5 x ULN or creatinine clearance ≥60 mL/min, proteinuria \<2+.
* Normal coagulation function (INR≤1.5).
* Agree and be able to comply with the plan during the study period. Provide written informed consent before entering the study screening.
Exclusion Criteria:
* Any other malignancy within 5 years prior to randomization, with the exception of cured in-situ carcinoma or basal cell carcinoma.
* Previous treatment with irinotecan/liposomal irinotecan.
* MSI-H/dMMR
* Massive pleural effusion or ascites requiring intervention.
* Active, uncontrolled bacterial, viral, or fungal infections that require systemic treatment.
* Active HIV, HBV, HCV infection.
* Combined with uncontrollable systemic diseases.
* Presence of severe gastrointestinal disease (including active bleeding, \> grade 1 obstruction , \> grade 1 diarrhea or gastrointestinal perforation)
* History of laparotomy, thoracotomy, or intestinal resection within 28 days before enrolment.
* Presence of interstitial pneumonia or pulmonary fibrosis.
* Allergy to or intolerance to therapeutic drugs or their excipients;.
* History of pulmonary hemorrhage/hemoptysis ≥ Grade 2 (defined as bright red blood of at least 2.5mL) within one month prior to enrollment.
* Presence of arterial embolism, severe bleeding (excluding bleeding caused by surgery) or tendency for existing embolism or severe bleeding within 6 months before enrollment.
* Patients with symptomatic central nervous system metastases.
* Documented serum albumin ≤3 g/dL
* Use of strong inhibitors or inducers of CYP3A, CYP2C8 and UGT1A1.
* Pregnant or breastfeeding women, or subjects of childbearing age who refuse contraception.
* Participated in other trial within 30 days prior to the first dose of study treatment.
* Patients who had received any intravenous antineoplastic therapy within 28 days or oral antineoplastic therapy within 14 days before the first dose of study drug
* Patients who are not suitable to participate in this trial for any reason judged by the investigator.
