Biomarker analyses from a phase III, randomized, open-label, first-line study of gefitinib (G) versus carboplatin/paclitaxel (C/P) in clinically selected patients (pts) with advanced non-small cell lung cancer (NSCLC) in Asia (IPASS)

Abstract

8006^ Background: IPASS demonstrated overall superiority of first-line G vs C/P for progression-free survival (PFS) in never/light ex-smokers with stage IIIB/IV adenocarcinoma NSCLC in Asia. PFS favored CP initially and then G. Outcome was correlated with biomarkers (preplanned exploratory objective). Methods: 683 patients provided tissue samples. Analyses included primary endpoint PFS (Cox proportional hazards) and secondary endpoint objective response rate (ORR; logistic regression) by biomarker status. Results: EGFR mutation (M) status was evaluable in 437 pts by Amplification Refractory Mutation System (ARMS; 60% M+). M+ pts had significantly longer PFS and higher ORR and M- pts significantly shorter PFS and lower ORR with G than C/P. In M unknown pts PFS and ORR were similar to overall population. Post hoc analysis of overall survival favored G in M+ pts (31% maturity; HR 0.78; 95% CI 0.50–1.20) and C/P in M- pts (53% maturity; HR 1.38; 95% CI 0.92–2.90); differences were not statistically significant and follow-up is ongoing. EGFR gene-copy number was evaluable in 406 pts by fluorescence in situ hybridization (FISH; 61% FISH +). Similar PFS and ORR results to analyses by M status were observed, driven by the overlap in EGFR FISH and M status. EGFR protein expression (PE) was evaluable in 365 pts by immunohistochemistry (73% PE+). PFS outcomes did not differ statistically between PE+ and PE-. ORR favored G in both PE+ and - pts. Conclusions: EGFR M status was a strong predictive biomarker for the efficacy of G vs C/P in this clinically selected first-line setting. [Table: see text] No significant financial relationships to disclose. ASCO Conflict of Interest Policy and Exceptions In compliance with the guidelines established by the ASCO Conflict of Interest Policy (J Clin Oncol. 2006 Jan 20;24[3]:519–521) and the Accreditation Council for Continuing Medical Education (ACCME), ASCO strives to promote balance, independence, objectivity, and scientific rigor through disclosure of financial and other interests, and identification and management of potential conflicts. According to the ASCO Conflict of Interest Policy, the following financial and other relationships must be disclosed: employment or leadership position, consultant or advisory role, stock ownership, honoraria, research funding, expert testimony, and other remuneration (J Clin Oncol. 2006 Jan 20;24[3]:520). The ASCO Conflict of Interest Policy disclosure requirements apply to all authors who submit abstracts to the Annual Meeting. For clinical trials that began accrual on or after April 29, 2004, ASCO's Policy places some restrictions on the financial relationships of principal investigators (J Clin Oncol. 2006 Jan 20;24[3]:521). If a principal investigator holds any restricted relationships, his or her abstract will be ineligible for placement in the 2009 Annual Meeting unless the ASCO Ethics Committee grants an exception. Among the circumstances that might justify an exception are that the principal investigator (1) is a widely acknowledged expert in a particular therapeutic area; (2) is the inventor of a unique technology or treatment being evaluated in the clinical trial; or (3) is involved in international clinical oncology research and has acted consistently with recognized international standards of ethics in the conduct of clinical research. NIH-sponsored trials are exempt from the Policy restrictions. Abstracts for which authors requested and have been granted an exception in accordance with ASCO's Policy are designated with a caret symbol (^) in the Annual Meeting Proceedings. For more information about the ASCO Conflict of Interest Policy and the exceptions process, please visit www.asco.org/conflictofinterest .