Molecular Predictors of Outcome With Gefitinib in a Phase III Placebo-Controlled Study in Advanced Non–Small- Cell Lung Cancer Fred R. Hirsch, Marileila Varella-Garcia, Paul A. Bunn Jr, Wilbur A. Franklin, Rafal Dziadziuszko, Nick Thatcher, Alex Chang, Purvish Parikh, José Rodrigues Pereira, Tudor Ciuleanu, Joachim von Pawel, Claire Watkins, Angela Flannery, Gillian Ellison, Emma Donald, Lucy Knight, Dinah Parums, Nicholas Botwood, and Brian Holloway A B S T R A C T Purpose The phase III Iressa Survival Evaluation in Lung Cancer (ISEL) trial compared gefitinib with placebo in 1,692 patients with refractory advanced non–small-cell lung cancer. We analyzed ISEL tumor biopsy samples to examine relationships between biomarkers and clinical outcome after gefitinib treatment in a placebo-controlled setting. Methods 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). Results 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. Conclusion EGFR gene copy number was a predictor of clinical benefit from gefitinib in ISEL. Additional studies are warranted to assess these biomarkers fully for the identification of patients most likely to benefit from gefitinib treatment. J Clin Oncol 24:5034-5042. © 2006 by American Society of Clinical Oncology INTRODUCTION Many translational and clinical cancer research ef- forts aim to identify biomarkers that may predict patients most likely to respond to treatment. The epidermal growth factor receptor tyrosine kinase in- hibitors (EGFR-TKIs) gefitinib and erlotinib have been studied extensively in clinical trials, 1-8 and the association of EGFR-related biomarkers with EGFR- TKI clinical outcome has also been investigated. Sensitivity to novel EGFR inhibitors may be influenced by a high EGFR gene copy number, with patients reported to experience increased ge- fitinib or erlotinib efficacy compared with a low EGFR gene copy number. 9-11 Mixed results have been reported for EGFR protein expression and response to EGFR-TKIs; no association was seen in the IRESSA Dose Evaluation in Advanced Lung Cancer (IDEAL) trials, 12 whereas others observed significant correlations between EGFR protein ex- pression and response or survival with gefitinib and erlotinib. 9,11,13 Phospho-Akt expression also seems to correlate with improved clinical out- come with gefitinib, but only in the subgroup of patients who coexpress EGFR. 14 Activating EGFR mutations have been re- ported in many patients responding to EGFR- TKIs, and seem to correlate with clinical response to EGFR-TKIs. 15-19 However, some patients with- out an EGFR mutation responded to EGFR-TKIs From the University of Colorado Cancer Center, Aurora, CO; Medical University of Gdansk, Gdansk, Poland; Christie Hospital, Manchester; AstraZeneca, Macclesfield, United Kingdom; Johns Hopkins Singapore International Medi- cal Center, Singapore; Tata Memorial Hospital, Mumbai, India; Arnaldo Vieira de Carvalho Cancer Institute, Sa ˜o Paulo, Brazil; Oncology Institute Ion Chiricuta, Cluj-Napoca, Romania; and Asklepios Fachkliniken, Gauting, Germany. Submitted March 3, 2006; accepted August 23, 2006. Supported in part by AstraZeneca; a National Cancer Institute-International Union Aganist Cancer Traslational Cancer Research Fellowship, funded by the National Cancer Institute (R.D.); and by Bristol-Myers Squibb and Pfizer (A.C.). Presented in part at the Annual Meet- ing of the American Association for Cancer Research-National Cancer Institute-European Organisation for Research and Treatment of Cancer, Philadelphia, PA, November 14-18, 2005. Authors’ disclosures of potential con- flicts of interest and author contribu- tions are found at the end of this article. Address reprint requests to Fred R. Hirsch, MD, PhD, University of Colo- rado Cancer Center, PO Box 6511, Mail Stop 8111, Aurora, CO 80045; e-mail: Fred.Hirsch@UCHSC.edu. © 2006 by American Society of Clinical Oncology 0732-183X/06/2431-5034/$20.00 DOI: 10.1200/JCO.2006.06.3958 JOURNAL OF CLINICAL ONCOLOGY O R I G I N A L R E P O R T VOLUME 24  NUMBER 31  NOVEMBER 1 2006 5034 Copyright © 2006 by the American Society of Clinical Oncology. All rights reserved. Downloaded from jco.ascopubs.org on April 17, 2008 . For personal use only. No other uses without permission.