Persons with advanced non-small cell lung cancer (NSCLC) characterized by tumors that express high levels of epidermal growth factor receptor (EGFR) are more likely to benefit from cetuximab (Erbitux) treatment and live longer than are those undergoing chemotherapy only, reveals the findings of a new study.
Previously, the addition of cetuximab to first-line chemotherapy significantly improved overall survival compared with chemotherapy alone in the phase 3 First-Line Erbitux in Lung Cancer (FLEX) study. In the current project, Professor Robert Pirker, MD, of the department of medicine at the Medical University of Vienna in Vienna, Austria, and colleagues explored the association between tumor EGFR expression level and clinical outcome in FLEX participants. Pirker’s research was funded by Merck KGaA, which has exclusive rights to develop and commercialize Erbitux outside the United States and Canada and co-exclusive rights to develop the drug in Japan (www.erbitux.com/index.aspx).
Tumor EGFR immunohistochemistry data were available for 99.6% percent (1,121 of 1,125) FLEX intention-to-treat population. The investigators used a scoring system of 0 to 300 to identify patients with high and low levels of the EGFR protein.
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Among the 345 evaluable patients whose tumors had high EGFR expression (defined as a score of 200 or higher), median survival was 12.0 months for those undergoing chemotherapy plus cetuximab vs 9.6 months for those receiving chemotherapy only, with no meaningful increase in side effects with cetuximab. After 2 years, 24% of the cetuximab recipients were alive, compared with 15% of those given chemotherapy alone.
In contrast, no corresponding survival benefit was seen among the 776 evaluable participants with low EGFR expression (9.8 months with the addition of cetuximab vs 10.3 months without).
In their report for The Lancet Oncology, Pirker and his fellow researchers concluded that high EGFR expression is a tumor biomarker that can predict survival benefit from the addition of cetuximab to first-line chemotherapy in persons with advanced NSCLC. They suggested that assessment of EGFR expression could offer a personalized treatment approach in that setting.
