Other Oncogene Mutations for Anti-EGFR Efficacy in Patients With Left-sided RAS-wild Type Metastatic Colorectal Cancer

Inclusion Criteria: 1. Informed consent signed before commencing any procedures related to the clinical trial. 2. Age ≥18 years. 3. ECOG status 0-2. 4. Life expectancy greater than 12 weeks as assessed by the investigator. 5. Verified diagnosis of colorectal adenocarcinoma (C18.5, C19, C20). 6. Metastatic unresectable form of the disease that has not previously received any systemic therapy for the metastatic process (previous neo-/adjuvant therapy completed at least 6 months before the detection of metastases is allowed). 7. Left-sided localization of the primary tumor (from the splenic flexure of the colon inclusive). 8. Verified wild type KRAS, NRAS determined from tumor tissue. 9. Satisfactory function of hematopoiesis and internal organs: * absolute number of neutrophils ≥ 1.5×10 9 /l; * platelets ≥ 100×10 9 /l; * hemoglobin ≥ 90 g/l. * creatinine clearance above 50 ml/min; * total bilirubin \<1.5 X the upper limit of normal; * ALT or AST \>5 X the upper limit of normal in the presence of liver metastases or \>2.5 X the upper limit of normal in the absence of liver metastases. 10. Availability of a sufficient amount of tumor material for molecular genetic research. Tumor material must be collected no more than 24 months before inclusion in the study. Exclusion Criteria: 1. Previous systemic therapy for metastatic disease. 2. Presence of KRAS/NRAS/V600E mutations (except for unknown BRAF status). 3. Uncertain KRAS/NRAS status 4. The presence of any other malignant tumor, with the exception of radically treated basal cell carcinoma, cervical cancer in situ, currently or within 5 years before inclusion in the study. Pregnant and lactating women, as well as planning pregnancy during the period of therapy in a clinical trial and 6 months after the end of therapy. 5. HIV infection, active hepatitis B, active hepatitis C. 6. Complicated primary tumor, requiring urgent surgical intervention. After it is eliminated, the patient can participate in the study. 7. The presence of a disease or condition that, in the opinion of the investigator, prevents the patient from participating in the study. 8. Impossibility of organizing central venous access.