Drug Insight: panitumumab, a human EGFR-targeted monoclonal antibody with promising clinical activity in colorectal cancer.

Colorectal cancer (CRC) is the second leading cause of cancer-related mortality in Western countries. Despite the progress achieved with the introduction of new cytotoxic agents, CRC recurrence rates for patients with resected stage II and/or stage III disease remain higher than 20%. Furthermore, for patients diagnosed with metastatic CRC, the median survival time remains below 2 years and cure is often an elusive goal. These data highlight the need for more-effective systemic therapies. The EGFR is frequently overexpressed in CRC and has been associated with the malignant phenotype. Numerous clinical trials are now investigating the role of EGFR-targeted agents in CRC and have produced some encouraging results. Panitumumab is a fully human IgG(2) monoclonal antibody that in a randomized phase III trial was shown to increase efficacy when added to best supportive care in patients with chemotherapy-refractory metastatic CRC. In phase I-III trials, panitumumab was safe and well tolerated, with most of its adverse effects related to some form of skin toxic effect. Early studies assessing the safety and efficacy of panitumumab alongside chemotherapy have also yielded promising results, and this combination is now being investigated in the first-line and second-line settings in randomized clinical trials.