First-line targeted therapies in the treatment of metastatic colorectal cancer – role of cetuximab

Worldwide, colorectal cancer (CRC) is the fourth most commonly diagnosed malignant disease and the second leading cause of cancer-related death in Western nations. In 2008 there were an estimated 148,810 new cases and 49,960 deaths in the US. For several years different chemotherapeutic regimens, based on fluoropyrimidines, irinotecan and oxaliplatin, have been used in advanced CRC, but survival is still unsatisfactory. New targeted therapies, including drugs and monoclonal antibodies (MoABs), show great promise in the fight against CRC and have shown activity in different disease settings. Cetuximab, a chimeric IgG1 monoclonal antibody that binds to the extracellular domain of epidermal growth factor receptor (EGFR), is active in metastatic colorectal cancer (mCRC). As an IgG1 antibody, cetuximab may exert its antitumor efficacy through both EGFR antagonism and antibody-dependent cell-mediated cytotoxicity. The combination of this drug with classical chemotherapies has shown better clinical profiles reflected in an improvement in overall and progression-free survival. Clinical trials established the role of cetuximab, particularly with irinotecan, in irinotecan-refractory/heavily pretreated patients. Whereas cetuximab has a clear indication in the salvage setting, its role in first-line therapy remains investigational. It is particularly encouraging that cetuximab may enhance curative opportunities in patients with early metastatic disease, suggesting that adding cetuximab in first-line therapy may downstage disease in some patients, and, as a result, allow potentially curative resection of previously unresectable metastases. In this review we will focus on the main epidermal growth factor receptor inhibitors demonstrating clinical benefit, and the role of cetuximab in first-line treatment of metastatic CRC.