521PMulticenter phase II study of biweekly XELIRI plus bevacizumab as a second-line therapy in patients with metastatic colorectal cancer (JSWOG-C3 study)

Background: Triweekly capecitabine plus irinotecan (XELIRI) is not completely regarded as a valid substitute for fluorouracil, leucovorin, and irinotecan (FOLFIRI) in metastatic colorectal cancer (mCRC) because of the potential for greater toxicity. Therefore, we conducted a phase II study to assess the efficacy and safety of biweekly XELIRI plus bevacizumab (BV) as second-line chemotherapy for mCRC. High dose BV (10 mg/kg) combined biweekly XELIRI as second-line chemotherapy was one of the first trial in the world. Methods: Patients with mCRC who had received prior chemotherapy including oxaliplatin based regimen were eligible for this study. Protocol treatment administrated capecitabine 1,000 mg/m2 twice daily from the evening of day 1 to the morning of day 8, intravenous irinotecan 150mg/m2 on day 1, and BV 10 mg/kg on day 1 every 2 weeks. The primary endpoint of this study were progression-free survival (PFS) and safety. The secondary endpoint were overall survival (OS), time to treatment failure (TTF), response rate (RR) and disease control rate (DCR). Results: Between January 2013 and July 2015, 51 patients were enrolled in this study. The patients’ characteristics were as follows: median age, 66 years (range 41–82); male/female, 29/22; The median PFS was 5.7 months (95% confidence interval, 4.2–7.2 months). The median OS was 13.4 months (95%CI, 11.4–16.7 months). The median TTF was 5.2 months (95%CI, 3.9–7.2 months). The response rate was 14%, and the disease control rate was 78%. Grade 3 or higher adverse events were mainly febrile neutropenia in two patients and hypertension in 14 patients (28.6%). One patient had grade 4 intestinal pneumonia but improved by intensive treatment. There were no other severe adverse events or treatment-related deaths. Conclusions: In mCRC patients, biweekly XELIRI + BV 10 mg/kg is effective and feasible as second-line chemotherapy. Biweekly XELIRI + BV is considered a useful substitute for FOLFIRI + BV in mCRC, and further study of this combination therapy is warranted. Legal entity responsible for the study: Japan Southwest Oncology Group Funding: Japan Southwest Oncology Group Disclosure: All authors have declared no conflicts of interest.