Bevacizumab-containing Regimen for Metastatic Colorectal Cancer Failed to Cytotoxic Treatment

Inclusion Criteria: * Signed informed consent obtained. * Subjects must be able to understand and willing to sign a written informed consent. * Subjects \> 18 years of age * Subjects must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 2. * Histological or cytological diagnosis of adenocarcinoma of the colon or rectum. * Subjects have unresectable metastatic lesions. * Subjects failed to respond to oxaliplatin, irinotecan and fluorouracil. * Subjects have at least one measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria measured within 4 weeks prior to registration. * Leukocytes ≥ 3.0 x109/ L, absolute neutrophil count (ANC) ≥ 1.5 x109/ L, platelet count ≥ 100 x109/ L, hemoglobin (Hb) ≥ 9g/ dL. * Total bilirubin ≤1.5 x the upper limit of normal (ULN). * Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 5 x ULN. * Amylase and lipase ≤ 1.5 x the ULN. * Serum creatinine ≤ 1.5 x the ULN. * Calculated creatinine clearance or 24 hour creatinine clearance ≥ 50 mL/ min. Exclusion Criteria: * Any previous or concurrent cancer that is distinct in primary site or histology from colorectal cancer within 5 years prior to this study. * Extended field radiotherapy within 4 weeks or limited field radiotherapy within 2 weeks prior to randomization. * Major surgical procedure, open biopsy, or significant traumatic injury within 4 weeks before start of study medication. * Uncontrolled hypertension. (systolic blood pressure \> 150 mmHg or diastolic pressure \> 90 mmHg despite optimal medical management). * Significant cardiovascular disease including unstable angina or myocardial infarction within 6 months before initiating study treatment or a history of ventricular arrhythmia * Arterial or venous thrombotic or embolic events such as cerebrovascular accident (including transient ischemic attacks), deep vein thrombosis or pulmonary embolism within the 6 months before start of study medication. * Any evidence of active infection. * Known history of human immunodeficiency virus (HIV) infection. * History of bleeding diathesis or coagulopathy. * History of interstitial pneumonitis or pulmonary fibrosis * Pregnancy or lactation at the time of study entry. * Any history of or currently known brain metastases. * Known dihydropyrimidine dehydrogenase (DPD) deficiency * Any illness or medical conditions that are unstable or could jeopardize the safety of the subjects and his/her compliance in the study. * Subjects with known allergy to the study drugs or to any of its excipients. * Current or recent (within 4 weeks prior to starting study treatment) treatment of another investigational drug or participation in another investigational study.