The Efficacy and Safety of Fruquintinib Plus Chemotherapy as Second-line Treatment in Metastatic Colorectal Cancer

Inclusion Criteria: * Aged 18-75years (inclusive); * Body weight ≥40 kg; * Histological or cytological confirmed colorectal cancer; * Expected survival \>12 weeks; * Fail in previous first-line standard therapy, which must include a fluorouracil (5-fluorouracil or capecitabine), oxaliplatin ; * At least one measurable lesion (according to RECIST1.1); * Adequate hepatic, renal, heart, and hematologic functions; * Negative serum pregnancy test at screening for women of childbearing potential. Exclusion Criteria: * Received radiation therapy, surgical procedure, chemotherapy, immunotherapy or molecular targeted therapy, or other investigational drugs within 4 weeks prior to treatment * Prior treatment with anti-angiogenic small molecule targeted drugs, such as fruquintinib, etc * Prior treatment with an irinotecan-based chemotherapy regimen * Symptomatic brain or meningeal metastases (except for patients with BMS who have received local radiotherapy or surgery for more than 6 months and whose disease is stable); * Patients with hypertension that cannot be well controlled by antihypertensive medication (systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg) * Have obvious clinical bleeding symptoms or obvious bleeding tendency within 3 months before treatment (bleeding \> 30 mL within 3 months, hematemesis, black feces, hematozoia), hemoptysis (fresh blood \> 5 mL within 4 weeks), etc. Treatment for venous/venous thrombosis events within the previous 6 months, such as cerebrovascular accident (including transient ischemic attack, cerebral hemorrhage, cerebral infarction), deep vein thrombosis, and pulmonary embolism; Long-term anticoagulant therapy with warfarin or heparin, or long-term antiplatelet therapy (aspirin ≥300 mg/day or clopidogrel ≥75 mg/day); * Tumor invasion of large vascular structures, such as pulmonary artery, superior vena cava or inferior vena cava, was found during screening, which was judged by the investigator to have a greater risk of bleeding; * Active heart disease, including myocardial infarction, severe/unstable angina, 6 months prior to treatment. Echocardiography examination left ventricular ejection fraction \< 50%, arrhythmia control is not good; * The patient has had other malignant tumors within 5 years (except cured basal cell carcinoma of the skin and carcinoma in situ of the cervix); * Allergy to the study drug or any of its excipients; * Severe infection with active or uncontrolled infection; * Any other disease, with clinical significance of metabolic abnormalities, abnormal physical examination or laboratory abnormalities, according to researchers, there is reason to suspect the patient has not suitable for the use of study drugs of a disease or condition (such as have a seizure and require treatment), or will affect the interpretation of results, or to make patients in high-risk situations; * Urine routine showed urine protein ≥2+, and 24-hour urine protein level \>1.0g.