Article: Cetuximab

Cetuximab (Erbitux®) is a chimeric monoclonal antibody given by intravenous injection for treatment of metastatic colorectal cancer and head and neck cancer.

Cetuximab is distributed inside the United States by ImClone Systems and Bristol-Myers Squibb, while it is distributed outside North America by Merck KGaA. It faces stiff competition from bevacizumab (Avastin), made by Genentech, and potential competition from a new drug currently under development by Abgenix.

Mode of action

Cetuximab is believed to operate by locking onto the epidermal growth factor receptors (EGFR) of cancer cells. This prevents normal epidermal growth factors from stimulating cell growth and repair.

Clinical uses

Cetuximab is used in metastatic colon cancer and is given concurrently with the chemotherapy drug irinotecan (Camptosar®), a form of chemotherapy that blocks the effect of DNA topoisomerase I, resulting in fatal damage to the DNA of affected cells. While there is a medical laboratory test to detect if a cancer tumor over expresses epidermal growth factor receptor(EGFR) on its cells surface, this over expression has recently been shown to not have any bearing on whether a patient will respond to Cetuximab or not. Whether this is because the current tests are just not sensitive enough to detect EGFR over expression or because EGFR over expression is not linked to the drugs effectiveness has not been established. Cetuximab was approved by the FDA in March 2006 after the publication of research performed by Dr J. Bonner [1] for use in combination with radiation therapy for treating squamous cell carcinoma of the head and neck (SCCHN) or as a single agent in patients who have had prior platinum-based thearpy.

The probability of successfully responding to Cetuximab therapy is linked to the incidence of ache like rash, one of the drugs side effects. The worse the rash that develops for the patient the higher the response rate.

ImClone insider trading scandal

The initial failure of ImClone Systems to prepare an acceptable FDA filing led to the infamous Martha Stewart insider trading scandal when ImClone's CEO sold ImClone shares and this information was leaked to Martha before the FDA announced its refusal to approve the drug for public use. Martha Stewart, Samuel D. Waksal (the founder and former CEO of ImClone), and their broker were indicted, and Stewart and Waksal were sentenced to prison. ImClone shares dropped sharply in the aftermath of the insider trading scandal.

A new clinical trial and FDA filing prepared by Imclone's partner Merck KGaA ("German Merck," not to be confused with the US company of similar name) resulted in an FDA approval of the drug in 2004 for use in colon cancer.

Erbitux® is one of the most expensive drugs available, costing over $17,000 per month for the average dose.