Phase II trial of irinotecan, S-1, and bevacizumab (IRIS/Bev) combination chemotherapy as second line for advanced colorectal cancer (NCCSG04).

Abstract

496 Background: The FIRIS study (Muro K et al. Lancet Oncol 2010;11:853-860) previously demonstrated the non-inferiority of Irinotecan plus S-1 (IRIS) to FOLFIRI for metastatic colorectal cancer (mCRC), with progression-free survival as the primary endpoint. IRIS plus bevacizumab (IRIS/Bev) was reported an active and generally well-tolerated first-line treatment for mCRC (Yuki et al. ASCO 2012 #3593). We planned a Phase II trial to evaluate the efficacy and safety of IRIS/Bev as second-line therapy for patients with mCRC. Methods: The study design was multicenter, single-arm, open-label phase II study. Eligible patients had to have mCRC with confirmed diagnosis of adenocarcinoma, history of oxaliplatin containing regimen as first-line therapy, an age from 20 to 80 years, ECOG performance status (PS) of 0-1. S-1 65 mg/m2 daily p.o. was given on days 1-14 and Irinotecan 75mg/m2 and Bevacizumab 10mg/kg i.v. were given on days 1 and 15 of a 28-day cycle. The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall response rate (OR), overall survival (OS), time to treatment failure (TTF) and safety. Results: From 08/12 until 11/06, 35 patients were enrolled. One patient did not start therapy. Thirty-four patients were investigated. Median age was 63 years (range, 38 to 82). Twenty-five patients were male. The mean of relative dose intensity of TS-1/Irinotecan/Bev were respectively 92.1%/87.0%/86.2%. The OR was 21.1% (7/33) and disease control rate was 84.8% (28/33). Median PFS was 9.3 months, median TTF was 8.2 month and median survival time 23.1 month. On safety analysis, the incidence of grade 3 or 4 adverse reactions were as follows: neutropenia, 14.7%; fatigue, 14.7%; white blood cell decreased, 11.8%; anorexia, 8.8%; anemia, 8.8%; diarrhea, 2.9%; proteinuria, 5.9%; thromboembolic event, 2.9%. Conclusions: IRIS/Bev is an active and well-tollarated second-line treatment for patients with mCRC. Clinical trial information: UMIN000001631.