Clinical Study of Apatinib Combined With Second - Line Chemotherapy for Metastatic Colorectal Cancer

Inclusion Criteria:

1. Male or female aged 18 to 70 years old;
2. Histologically or cytologically proven patients with metastatic colorectal cancer have undergone a first-line standard regimen recommended by the NCCN guidelines for progression;
3. According to the RECIST 1.1 criteria, the patient has at least one target lesion that can measure the diameter;
4. ECOG PS ≤ 2;
5. Expected survival time of more than 12 weeks.
6. The level of organ function must meet the following requirements:

   Bone marrow: neutrophil count (ANC) ≥ 1.5 × 10\^9/L, platelet ≥ 75 × 10\^9/L, hemoglobin ≥ 90g/L.

   Liver: serum bilirubin ≤ 2 times the upper limit of normal, aminotransferase AST and ALT ≤ 2.5 times the normal upper limit.

   Kidney: Serum creatinine ≤1.5 times upper limit of normal.
7. Patient compliance is good;
8. Understand and voluntarily sign a written informed consent.

Exclusion Criteria:

1. Other previous or concurrent malignancy, except cured skin basal cell carcinoma and cervical carcinoma in situ;
2. Already known to be allergic to apatinib or any excipient;
3. Use unapproved drugs or other test medications within 4 weeks prior to enrollment;
4. There are many factors that affect oral medications (such as inability to swallow, chronic diarrhea and intestinal obstruction);
5. Patients with a history of CNS metastases or CNS metastases;
6. A history of bleeding, with any serious grading within 4 weeks prior to screening reaching a bleeding event of 3 degrees Celsius or greater in CTCAE4.0;
7. Serious infection;
8. Serious cardiovascular disease: uncontrolled hypertension, unstable angina, grade 3-4 heart failure (NYHA standard), congestive heart failure;
9. urinary routine urinary protein ≥ ++ and confirmed 24-hour urinary protein quantitation\> 1.0 g;
10. Within 30 days after major surgery;
11. Thrombotic disease. Anemia or venous thrombosis occurred in the previous year, such as cerebrovascular accident (including transient ischemic attack), deep vein thrombosis, pulmonary embolism, etc.;
12. Those with history of psychotropic substance abuse who can not be abstinent or have mental disorders;
13. Have clinical symptoms, need clinical intervention pleural effusion or ascites;
14. At the investigator's discretion, there is a serious concomitant condition that compromises the patient's safety or affects the patient in completing the study.