This study is a prospective, single-arm, multicenter exploratory clinical study aimed at evaluating the efficacy and safety of iparomlimab and tuvonralimab combined with bevacizumab and alternating triweekly CAPOX/mCAPIRI regimen as first-line treatment for unresectable advanced colorectal cancer. The study plans to enroll 70 patients with unresectable advanced metastatic colorectal cancer. After evaluation and confirmation of meeting enrollment criteria, patients will receive treatment with iparomlimab and tuvonralimab combined with bevacizumab and alternating triweekly CAPOX/mCAPIRI regimen. The primary endpoint of the study is ORR, and secondary endpoints include PFS, DoR, OS, and safety.

Inclusion Criteria:

• 1. Age 18-75 years;

• 2. Patients with histologically or cytologically confirmed unresectable, advanced colorectal cancer;

• 3. No prior systemic treatment;

• 4. ECOG PS score ≤2;

• 5. Expected survival ≥3 months;

• 6. MSS/MSI-L status;

• 7. At least one evaluable lesion based on RECIST 1.1 criteria;

• 8. No prior systemic chemotherapy or other systemic therapy, or only received adjuvant chemotherapy with disease progression or recurrence within 6 months after completion of treatment;

• 9. Adequate organ function reserve, with specific hepatic, renal, and hematologic parameters as follows:

  1. White blood cell count ≥3.5×10⁹/L
  2. Absolute neutrophil count ≥1.5×10⁹/L
  3. Hemoglobin ≥100 g/L
  4. Platelets ≥80×10⁹/L
  5. Serum liver enzymes ≤2.5× upper limit of normal (ULN) in patients without liver metastases
  6. Serum liver enzymes ≤5× ULN in patients with liver metastases
  7. Serum bilirubin ≤1.5× ULN
  8. Serum creatinine ≤1.5× ULN

• 10. No history of other malignancies;

• 11. Voluntary participation in this study with signed informed consent.

Exclusion Criteria:

• 1. Prior hypersensitivity to any of the study drugs;
• 2. Active or known or suspected autoimmune disease requiring systemic treatment, including but not limited to autoimmune hepatitis, interstitial pneumonia, uveitis, enteritis, hepatitis, hypophysitis, vasculitis, nephritis, hyperthyroidism, thyroid dysfunction, asthma requiring bronchodilator intervention;
• 3. Presence of non-measurable lesions (e.g., pleural effusion/ascites, carcinomatous lymphangitis, diffuse liver involvement, bone metastases);
• 4. Pregnant or lactating women;
• 5. Uncontrolled symptomatic brain metastases or psychiatric disorders preventing accurate expression of subjective symptoms;
• 6. Vital organ function failure;
• 7. Conditions affecting drug absorption/distribution/metabolism/excretion (e.g., seizures, central nervous system diseases, cognitive impairment due to psychiatric disorders, chronic diarrhea, cachexia, etc.);
• 8. Patients with complete or incomplete intestinal obstruction;
• 9. History of severe cardiac disease (including congestive heart failure, uncontrolled high-risk arrhythmia, angina requiring medication, definite valvular heart disease history, severe myocardial infarction, refractory hypertension);
• 10. Active infection requiring systemic treatment;
• 11. Known history of HIV infection;
• 12. Known history of hepatitis B or active hepatitis C virus infection;
• 13. Other conditions deemed unsuitable for enrollment by the investigator.