Cetuximab plus XELIRI or XELOX for first-line therapy of metastatic colorectal cancer.

Modern chemotherapy combinations for metastatic colorectal cancer (mCRC) comprise infusional 5-fluorouracil (5-FU), leucovorin, and irinotecan or oxaliplatin. The fluoropyrimidine derivative capecitabine is at least as effective as 5-FU plus leucovorin bolus regimens. It displays a favorable toxicity profile and offers the advantages of oral administration. The epidermal growth factor receptor antibody cetuximab induces synergistic antitumor activity when combined with chemotherapy. In pretreated patients, cetuximab can restore the sensitivity to irinotecan and, therefore, has been registered in this setting. Several phase I/II trials have investigated the combination of cetuximab with irinotecan-based or oxaliplatin-based chemotherapy for the first-line treatment of mCRC. These combinations have been proven to be safe and have provided promising efficacy data. A recent phase III trial confirmed improved progression-free survival, response rates, and a particularly significant increase of secondary resection rates for the combination of FOLFIRI (infusional 5-FU/leucovorin/irinotecan) plus cetuximab compared with FOLFIRI alone. In this review, we discuss the background of combining XELIRI (capecitabine/irinotecan) or XELOX (capecit-abine/oxaliplatin) with cetuximab for the first-line treatment of mCRC and present available data of these combined cytotoxic and targeted treatment approaches.