Capecitabine/irinotecan in colorectal cancer: European early-phase data and planned trials

Capecitabine (Xeloda) and irinotecan (CPT-11, Camptosar) exhibit single-agent activity in colorectal cancer, have nonoverlapping major toxicities, and exhibit a synergistic effect in tumor xenograft models. European early-phase trials of the combination in patients with metastatic colorectal cancer indicate good response rates across doses tested and manageable toxicities, with available data supporting use of a regimen of oral capecitabine at 1,000 mg/m2 twice daily on days 1 to 14 plus IV irinotecan at 250 mg/m2 on day 1 every 21 days in this setting. The European Organisation for Research and Treatment of Cancer has planned a phase III trial (EORTC 40015) comparing this regimen of capecitabine/irinotecan with infusional fluorouracil (5-FU)/leucovorin plus irinotecan in approximately 700 patients with metastatic colorectal cancer. The QUASAR (Quick and Simple and Reliable) 2 adjuvant trial will compare 5-FU/leucovorin with capecitabine/irinotecan given over 6 months as adjuvant therapy in patients with stage II/III colorectal cancer. These trials will help define the roles of this combination in the treatment of colorectal cancer.