Anti-Epidermal Growth Factor Receptor Antibodies in the Treatment of Metastatic Colorectal Cancer

Targeting the epidermal growth factor receptor (EGFR), an important component in carcinogenesis, is an attractive therapeutic option for selective anticancer therapy. Several EGFR inhibitors, mostly monoclonal antibodies and tyrosine kinase inhibitors are under investigation in the treatment of colorectal cancer. Although there has been some progress in the treatment of colorectal cancer with combination chemotherapy, the repertoire of active agents is still limited. More recently the anti-EGFR drugs cetuximab and panitumumab have made an impact in the treatment of metastatic disease but with variable response rates. Although the appearance of a skin rash confers a higher response rate, immunohistochemical staining of EGFR at baseline does not. Several studies have now focused on identifying predictive biological markers at a molecular level. Exciting data has demonstrated KRAS mutation status to be the first predictive marker of response to anti-EGFR monoclonal antibodies (mAbs) and has led a new era in the development of targeted therapies in colorectal malignant disease. The aim of this review is to evaluate the impact of anti-EGFR therapies in the treatment of metastatic colorectal cancer; and to present the current data on predictive markers including KRAS status, PTEN expression and germinal gene polymorphisms. The relevant patents are discussed.