Epidermal growth factor receptor as a target: recent developments in the search for effective new anti-cancer agents.

A number of cancer chemotherapeutics targeting the epidermal growth factor receptor (EGFR) are in development. These compounds were designed to either bind to the EGFR or inhibit signal transduction after receptor activation. Classes of inhibitory compounds include small molecules and humanized monoclonal antibodies. Many of these compounds are relatively far advanced in development. Proof of principle, with evidence of anti-tumour activity and inhibition of EGFR activation/phosphorylation, has already been demonstrated in some instances. Although these new compounds offer exciting opportunities, they bring with them real challenges in terms of the selection of appropriate trial designs as well as surrogate endpoints.