Drug Update: Erbitux (cetuximab)

The US Food and Drug Administration (FDA) is considering a supplemental biologics license application from ImClone Systems Inc requesting that approved uses of Erbitux be expanded to include first-line treatment of recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN) in combination with platinum-based chemotherapy. ImClone, which prepared the application in partnership with Bristol-Myers Squibb, requested priority review and anticipates a decision from the FDA in 6 months.

Several types of head and neck cancer cells produce excessive amounts of epidermal growth factor receptor (EGFR), a protein receptor on the cell’s surface that is involved in regulating its growth. Erbitux is a monoclonal antibody that binds to EGFRs, blocking phosphorylation and activation of receptor-associated kinases. This inhibits cell growth, induces apoptosis, and decreases matrix metalloproteinase and the production of vascular endothelial growth factor. Treatments for head and neck cancers typically are associated with significant toxicity. Erbitrux is believed to have reduced toxicity compared with other treatments.

Head and neck cancers account for approximately 5% of all invasive cancers. The American Cancer Society estimates that 47,500 people receive a diagnosis of head and neck cancer each year in the United States annually and approximately 11,200 will die from head and neck cancers this year. Squamous cell is the predominant pathology for these cancers, and SCCHN has a cure rate of less than 50%. The 5-year survival rate for patients whose SCCHN is diagnosed in its earliest stages ranges from 70% to 90%. The majority of patients, however, present with advanced SCCHN, which has a 3-year survival rate of approximately 30%.

ImClone applied for the supplemental biologics license after receiving encouraging results from the Phase 3 EXTREME study in Germany. In this multi-center study, researchers randomly assigned 442 patients with untreated stage III or IV recurrent and/or metastatic SCCHN to receive cisplatin plus 5-fluorouracil (5-FU) or carboplatin plus 5-FU either alone or in combination with Erbitux. On average, patients who received Erbitux in conjunction with one of the platinum-based therapies survived approximately 2.7 months longer than patients in the group that received only chemotherapy—a significant finding (median survival, 10.1 vs 7.4 months, respectively). The study also determined that rates of progression-free survival and response were greater for the group of patients treated with Erbitux and platinum-based therapy combined.

First approved in 2004 for the treatment of advanced metastatic colon or rectal cancers, Erbitux received approval from FDA in 2006 to treat recurrent or metastatic SCCHN in patients for whom platinum-based therapy proved unsuccessful. Erbitux can also be used as adjuvant treatment to radiation for patients who have locally or regionally advanced SSCHN.

For a more detailed explanation of how Erbitux works, you can visit the manufacturer’s Web site to watch an animated clip of its mechanism of action.