Interim analysis of a single-arm, phase II study of bevacizumab (BV) with modified OPTIMOX1 as first-line treatment of patients with metastatic colorectal cancer (mCRC): TCOG-GI0802.

Abstract

578 Background: BV is widely used for treatment of metastatic colorectal cancer (mCRC) patients. Although BV was often administrated to mCRC patients in combination with oxaliplatin, optimal schedule remains unclear. Many mCRC patients cannot continue to use oxalipatin because of cumulative neurotoxity, which decreases patient's QOL and motivation.We postulated that modification of oxaliplatin schedule would improve TTF in intermittent oxaliplatin usage. Therefore, we planned to use BV with original OPTIMOX1 adiministration schedule; modified oxaliplatin dose (85 mg/m3). Methods: Patients were enrolled with the criteria excluding neuropathy, PS ≥ 1, or no previous usage of oxaliplatin and BV, and then were received modified FOLFOX6 regimen (L-OHP 85 mg/m2, l-LV 200 mg/m2, 5-FU 400 mg/m2 bolus, 5-FU 2,400 mg/m2 46h continuous infusion) plus BV (5 mg/kg) q2wks x 6 cycles, followed sLV5FU2 (omit L-OHP) plus BV x 12 cycles regimen. After that, oxaliplatin reintroduction was done and mFOLFOX6 plus BV regimen was continued until PD. The evaluation of antitumor effect was done according to RECIST Criteria. Results: 40 patients accrued this trial. Median age was 65 years old. PS0: 89.5%, male: 75%, female: 25%, colon: 65.8%, rectal: 31.6%,colon + rectal: 2.6%. During initial 6 cycles of chemotherapy, 90% patients could continue chemotherapy. Response rate was 50%, and clinical benefit (including SD) was 92.1%. During Intial 6 cycles, G3 neuropathy occurred 2.6%, and G2 were 5%. Most frequent toxicity (≥G3) was neutropenia (30.8%) and anorexia (5.3%). One patient could complete the scheduled regimen. This patient continued mFOLFOX6+BV for 12 cycles after reintroduction keeping with PS 0, and was received FOLFIRI+BV regimen as second-line chemotherapy. Further information are under examination. Conclusions: This administration schedule was well tolerated and could continue chemotherapy longer than usual method. sLV5FU2+BV regimen was not affected reintroduction rate and progression free survival. BV with mOPTIMOX1 regimen can be expected to become a good treatment options for mCRC patients. No significant financial relationships to disclose.