PD-1 Antibody Plus Bevacizumab and CAPOX as First-line Treatment for RAS-mut MSS mCRC

Inclusion Criteria:

• Histologically or cytologically confirmed non resectable, locally advanced ormetastatic colorectal cancer;
• No previous anti-tumor treatment for metastatic diseases;
• KRAS/NRAS mutation;
• Eastern Cooperation Oncology Group (ECOG) performance status of 0-1;
• Life expectancy ≥ 3 months;
• Adequate organ and bone marrow functions: Absolute neutrophil count≥1.5x10^9/L; Platelet count≥100x10^9/L; Hemoglobin≥9g/dL; Serumbilirubin<1.5x the upper limit of normal(ULN); Alanine aminotransferase(ALT) and aspartateaminotransferase(AST)<1.5x ULN; Serum creatinine<1.5x ULN; Endogenous creatinine clearancerate ≥ 50ml / min;
• Women of childbearing age need to take effective contraceptive measures.

Exclusion Criteria:

• Previous treatment with vascular endothelial growth factor receptor (VEGFR) inhibitorsor previous use of immune checkpoint inhibitors;
• With BRAF mutation or MSI-H status;
• Other untreated or concurrent tumors (except cervical carcinoma in situ, treated basalcell carcinoma or superficial bladder tumor, or if the tumor is cured and there is noevidence of disease for more than 3 years);
• Have received other systemic anti-tumor treatments, including chemotherapy, signaltransduction inhibitors, hormone therapy and immunotherapy within 4 weeks beforeenrollment;
• There was central nervous system (CNS) metastasis or previous brain metastasis beforeenrollment;
• Have received any surgery or invasive treatment or operation within 4 weeks beforeenrollment;
• Have received Local anti-tumor therapy such as hepatic artery interventionalembolization, liver metastasis cryoablation or radiofrequency ablation within 4 weeksbefore enrollment;
• Uncontrolled malignant ascites;
• Participated in other clinical trials within 4 weeks before enrollment, and receivedcorresponding experimental drug treatment;
• Allergic to the study drug or any of its adjuvants;
• International normalized ratio (INR) > 1.5 or partially activated prothrombin time (APTT) > 1.5 × ULN；
• The researchers judged clinically significant electrolyte abnormalities;
• Hypertension that cannot be controlled by drugs, which is specified as: systolic bloodpressure ≥ 140 mmHg and / or diastolic blood pressure ≥ 90 mmHg; Patients currentlyhave poorly controlled diabetes (fasting glucose level is greater than CTCAE grade 2after regular treatment);
• Patients with dysphagia, active peptic ulcer, intestinal obstruction, activegastrointestinal bleeding, peptic perforation, malabsorption syndrome or uncontrolledintestinal inflammatory diseases;
• Any disease or state affecting drug absorption before enrollment, or the patientcannot take oral medication;
• Patients with obvious evidence of bleeding tendency or medical history within 3 monthsbefore enrollment, hemoptysis or thromboembolism within 12 months;
• Cardiovascular diseases with significant clinical significance, including but notlimited to acute myocardial infarction, severe / unstable angina pectoris or coronaryartery bypass grafting within 6 months before enrollment; Congestive heart failure,New York Heart Association (NYHA) grade > 2; ventricular arrhythmia requiring drugtreatment; LVEF (left ventricular ejection fraction) < 50%;
• Active infection or serious infection that is not controlled by drug (≥CTCAE v5.0Grade 2）;
• History of clinically significant hepatic disease, including, but not limited to,known hepatitis B virus (HBV) infection with HBV DNA positive (copies ≥1×10^4/ml or >2000 IU/ml); known hepatitis C virus infection with HCV RNA positive (copies ≥1×10^3/m); hepatitis and cirrhosis;
• Women who are pregnant or lactating;
• Urinary protein ≥ ++, and the 24-hour urine protein quantification is greater than 1.0g;
• Have any other disease, metabolic disorder, physical examination anomaly, abnormallaboratory result, or any other conditions that makes the subject not suitable forenrolling according to the judgment of the investigator.