Research background and purpose:

Patients with advanced colorectal cancer face the dilemma of limited treatment options and poor efficacy in the third line treatment stage. Although regorafenib and immune checkpoint inhibitors bring hope to some patients, the efficacy still faces bottlenecks for the vast majority of microsatellite stable patients who are insensitive to immune monotherapy. This study is based on the multi mechanism synergistic theory of "immune activation+vascular inhibition+targeted killing". It innovatively combines autologous DC-CIK cell immunotherapy, domestic PD-1/CTLA-4 bispecific antibody (aparolitovorelli monoclonal antibody), and multi-target tyrosine kinase inhibitor (regorafenib) to evaluate the efficacy and safety of this triple therapy as a third line treatment for advanced colorectal cancer, and explore its immunological mechanism.

Research content and methods:

This study is a single arm, open label clinical trial. Plan to enroll advanced colorectal cancer patients who have previously failed second-line standard treatment. All participants will receive the following combination therapy regimen:

1. Epaglitovirizumab: 5.0 mg/kg, intravenous injection, once every 21 days.
2. Regorafenib: 120mg, once daily, orally, 1-21 days, repeated every 28 days.
3. DC-CIK cell therapy: Collect, culture, and transfuse cells during specific cycles.

The study will strictly follow the protocol for efficacy evaluation (based on RECIST 1.1 standards) and safety monitoring, and a strict quality control and risk management system will be established.

Main evaluation indicators and expected outcomes:

• Primary endpoint: Objective response rate and safety.
• Secondary endpoints: progression free survival, overall survival, duration of remission, and treatment-related immunological responses.
• Expected outcome: This study is expected to provide a promising new comprehensive treatment strategy for chemotherapy resistant advanced colorectal cancer, especially MSS type patients, and break through existing efficacy bottlenecks. The research findings will provide high-level evidence-based medicine for the clinical application of this combined approach and lay the foundation for understanding its synergistic mechanism.

Inclusion Criteria:

-1. Sign written informed consent before implementing any experimental procedures; 2. Male or female ≥ 18 years old, ≤ 75 years old; 3. ECOG PS score is 0-1 points; 4. Patients with metastatic colorectal cancer confirmed by histology or cytology; 5. Expected survival time>3 months;

Exclusion Criteria:

-1. It is known that there is active CNS metastasis and/or cancerous meningitis; 2. Chest fluid, ascites, and pericardial effusion that require drainage due to clinical symptoms; 3. Any life-threatening bleeding events that have occurred within the past 3 months, including the need for blood transfusion therapy, surgery or local treatment, and continuous medication therapy; 4. Uncontrollable hypertension, with systolic blood pressure>150mmHg or diastolic blood pressure>90 mmHg after optimal medical treatment, history of hypertensive crisis or hypertensive encephalopathy; 5. Human immunodeficiency virus (HIV) infected individuals (HIV 1/2 antibody positive), known syphilis infected individuals;