Fruquintinib and Raltitrexed Versus Fruquintinib Monotherapy in Advanced Colorectal Cancer

Inclusion Criteria: 1. no less than 18 years old 2. confirmed by histopathological examination, recurrent/metastatic colorectal adenocarcinoma 3. had received at least two lines standard chemotherapy and failed. These standard regimens must include fluorouracil, oxaliplatin, and irinotecan. Treatment failure was defined as disease progression within 3 months after the last treatment or intolerance of toxicity or side effects during treatment ; Note: A. each line of treatment shall include more than one cycle of chemotherapeutic agents; B. adjuvant/neoadjuvant therapy is allowed in the former treatment. If recurrence or metastasis occurs during adjuvant/neoadjuvant therapy or within 6 months after completion, adjuvant/neoadjuvant therapy is considered a failure of first-line chemotherapy for the advanced disease; C. Prior antitumor therapy regimens using chemotherapy combined with cetuximab or bevacizumab were permitted. 4. with one or more measurable lesions, according to RECIST criteria, version 1.1; 5. Eastern Cooperative Oncology Group (ECOG) performance score(PS) from 0 to 2; 6. Life expectancy no less than 12 weeks; 7. Acceptable hematologic, hepatic, and renal function within 7 days from screening： the blood neutrophil count≥1.5x109 /L; hemoglobin ≥ 9.0 g/dl，the blood platelet count≥80 x109 /L, total bilirubin \< 1.5 x upper normal limit（UNL), alanine aminotransferase（ALT） and aspartate transaminase（AST）\< 2.5 x UNL(\< 5 x UNL for patients with live metastasis), serum creatinine≤1 x UNL，endogenous creatinine clearance rate \>50ml/min 8. Women of reproductive age need to take effective contraceptive measures. 9. Participate in this study voluntarily and sign informed consent. Understand the purpose of this study and the necessary procedures. Good compliance to cooperate with the follow-up. Exclusion Criteria: 1. urine protein 2 + or above, or 24 hours urinary protein quantitative acuity 1.0 g / 24 h 2. Abnormal coagulation function or those receiving thrombolytics or anticoagulants 3. Patients with tendency of gastrointestinal hemorrhage, including active peptic ulcer with fecal occult blood ++, hematemesis or melena within 3 months 4. Received other systemic anti-tumor therapy, including cell signal transduction inhibitors, drug therapy, immune therapy within 3 weeks 5. With uncontrolled high blood pressure (systolic blood pressure \> 140 MMHG, diastolic blood pressure \> 90 MMHG) 6. Radiotherapy therapy for target lesions 7. symptomatic cerebral or meningeal metastasis; 8. Uncontrolled pleural or peritoneal effusion 9. Undergoing dialysis 10. Severe or uncontrolled infection 11. With multiple factors that affecting oral administration 12. Former exposed to any VEGFR tyrosine kinase inhibitors (e.g regorafenib, apatinib, anlotinib etc.) for treatment 13. Raltitrexed treatment for more than one cycle in former line therapy