Epidermal Growth Factor Receptor Mutations and Gene Amplification in Non–Small-Cell Lung Cancer: Molecular Analysis of the IDEAL/INTACT Gefitinib Trials

Purpose Most cases of non–small-cell lung cancer (NSCLC) with dramatic responses to gefitinib have specific activating mutations in the epidermal growth factor receptor (EGFR), but the predictive value of these mutations has not been defined in large clinical trials. The goal of this study was to determine the contribution of molecular alterations in EGFR to response and survival within the phase II (IDEAL) and phase III (INTACT) trials of gefitinib. Patients and Methods We analyzed the frequency of EGFR mutations in lung cancer specimens from both the IDEAL and INTACT trials and compared it with EGFR gene amplification, another genetic abnormality in NSCLC. Results EGFR mutations correlated with previously identified clinical features of gefitinib response, including adenocarcinoma histology, absence of smoking history, female sex, and Asian ethnicity. No such association was seen in patients whose tumors had EGFR amplification, suggesting that these molecular markers identify different biologic subsets ...