Escalated Dose of Irinotecan in mCRC

Control group: Regimen for treatment consisted of bevacizumab (Avastin) 5mg/Kg (IV infusion) on day 1, follow by irinotecan (180 mg/m2 as a 120-min IV infusion), LV (400 mg/m2 IV infusion over 2 hours), and 5-FU (2800 mg/m2 IV infusion over a 46-hour period), repeated every 2 weeks. Study group: FOLFIRI (infusional fluorouracil/leucovorin plus irinotecan) + Bevacizumab. The dosage of irinotecan is adjusted to the UGT1A1 genotyping The wild-type (6/6) of UGT1A1: Regimen for treatment consisted of bevacizumab (Avastin) 5mg/Kg (IV infusion) on day 1, follow by irinotecan (180 mg/m2 as a 120-min IV infusion), LV (400 mg/m2 IV infusion over 2 hours), and 5-FU (2800 mg/m2 IV infusion over a 46-hour period), repeated every 2 weeks. After 2 cycles of each different dose of irinotecan, we will observe the adverse effects (AEs) of hematological / non-hematological. If the grade is under the grade 2, we will escalate the dose of 30 mg/m2 gradually. The estimated maximal dose of irinotecan is 260 mg/m2. The (6,7) type of UGT1A1: Regimen for treatment consisted of bevacizumab (Avastin) 5mg/Kg (IV infusion) on day 1, follow by irinotecan (180 mg/m2 as a 120-min IV infusion), LV (400 mg/m2 IV infusion over 2 hours), and 5-FU (2800 mg/m2 IV infusion over a 46-hour period), repeated every 2 weeks. After 2 cycles of each different dose of irinotecan, we will observe the adverse effects (AEs) of hematological / non-hematological. If the grade is under the grade 2, we will escalate the dose of 30 mg/m2 gradually. The estimated maximal dose of irinotecan is 240 mg/m2. The (7,7) type of UGT1A1: Regimen for treatment consisted of bevacizumab (Avastin) 5mg/Kg (IV infusion) on day 1, follow by irinotecan (120 mg/m2 as a 120-min IV infusion), LV (400 mg/m2 IV infusion over 2 hours), and 5-FU (2800 mg/m2 IV infusion over a 46-hour period), repeated every 2 weeks. After 2 cycles of each different dose of irinotecan, we will observe the adverse effects (AEs) of hematological / non-hematological. If the grade is under the grade 2, we will escalate the dose of 30 mg/m2 gradually. The estimated maximal dose of irinotecan is 180 mg/m2.