Phase I study of bevacizumab combined with irinotecan and S-1 as second-line chemotherapy in patients with advanced colorectal cancer

Abstract

The combination of an oral fluoropyrimidine derivative, S-1, and irinotecan has been reported to be a promising regimen for advanced colorectal cancer. However, the safety and efficacy of bevacizumab (BV) to combine with irinotecan and S-1 has not been determined. The aim of the study was to determine the maximum tolerated dose (MTD) and recommended dose (RD) of BV combined with irinotecan plus S-1, and to observe the safety and efficacy of this regimen as second-line chemotherapy in patients with advanced colorectal cancer. This study initially had been planned as a phase I/II study. Eighty mg/m(2) of irinotecan on days 1 and 8, 80 mg/m(2) of S-1 for 14 consecutive days, and two doses of BV (Level 1; 10 mg/kg, Level -1; 7.5 mg/kg) were administered on day 1 every 3 weeks. Fourteen patients were enrolled in phase I of the study between January 2008 and September 2010. Dose-limiting toxicities were diarrhea, abdominal pain, and infection. The MTD and RD of BV were determined to be 10 mg/kg and 7.5 mg/kg, respectively. The main adverse events were leukopenia, anorexia, and diarrhea. There were no treatment-related deaths. An independent review committee was scheduled to evaluate safety in phase I, but this trial closed early due to toxicity. This study identified the risk of gastrointestinal toxicity with the combination of irinotecan, S-1 and BV as second-line chemotherapy in patients with advanced colorectal cancer.