Molecular Predictors of Outcome With Gefitinib in a Phase III Placebo-Controlled Study in Advanced Non–Small-Cell Lung Cancer

Biomarkers included epidermal growth factor receptor (EGFR) gene copy number by fluorescence in situ hybridization (n = 370); EGFR (n = 379) and phosphorylated Akt (p-Akt) protein expression (n = 382) by immunohistochemistry; and mutations in EGFR (n = 215), KRAS (n = 152), and BRAF (n = 118).

High EGFR gene copy number was a predictor of a gefitinib-related effect on survival (hazard ratio [HR], 0.61 for high copy number and HR, 1.16 for low copy number; comparison of high v low copy number HR, P = .045). EGFR protein expression was also related to clinical outcome (HR for positive, 0.77; HR for negative, 1.57; comparison of high v low protein expression HR, P = .049). Patients with EGFR mutations had higher response rates than patients without EGFR mutations (37.5% v 2.6%); there were insufficient data for survival analysis. No relationship was observed between p-Akt protein expression and survival outcome, and the limited amount of data collected for KRAS and BRAF mutations prevented any meaningful evaluation of clinical outcomes in relation to these mutations.