ALK and EGFR mutation analysis in a phase II trial of cisplatin/pemetrexed in Japanese patients with advanced nonsquamous non-small cell lung cancer.

Abstract

e18017 Background: Recently, ethnic differences and genotypes such as EGFR mutation (EGFRm) or fusion gene (ALK translocation: ALKt) are important factors in non-small cell lung cancer (NSCLC) treatment. Pemetrexed (P)/cisplatin (C) is one of the standard care for advanced non-squamous (Nsq) NSCLC. However, the efficacy of the CP regimen has not been well examined in Japanese Nsq NSCLC patients (pts); furthermore, the difference in efficacy between genotypes was not thoroughly examined. Therefore, the present study was conducted to evaluate the efficacy of the CP regimen in Japanese Nsq NSCLC pts, and to determine whether EGFRm and ALKt impacted the treatment. Methods: This study was conducted from May 2009 to December 2010. Pts were eligible for this study if they had histologically or cytologically confirmed recurrent or metastatic Nsq NSCLC previously untreated with chemotherapy, an ECOG performance status of 0 or 1, life expectancy of more than 12 weeks, and adequate organ function. Pts received C (75 mg/m2) plus P (500 mg/m2) on day 1 every 3 weeks. Of the 50 pts initially enrolled, 49 were evaluated, and 43 tumor samples were available for analysis. Most pts were male (80%), and 80% of the pts had adenocarcinoma. The primary endpoint was the response rate that was evaluated according to RECIST. EGFRm was examined using PCR-based methods, and the ALK fusion protein was examined using a highly sensitive IHC method in the available tumor specimens. Although the CP regimen demonstrates consistent efficacy in Japanese Nsq NSCLC pts, EGFRm and ALKt may have impacted this treatment. Results: The objective response rate and disease control rate in all pts were 44.9% and 79.6%, respectively. The median progression-free survival was 4.4 months, and the 1-year survival was 73.5%. Toxicities were mild; no new toxicity profile was identified. Among the 43 samples, the following mutations were identified: 9 EGFRm (21%), 5 ALKt (12%), and 29 wild-type (67%). Objective response was observed in 6 (66.7%) EGFRm, 2 (40%) ALKt, and 13 (44.8%) wild-type. Conclusions: Although the CP regimen demonstrates consistent efficacy in Japanese Nsq NSCLC pts, EGFRm and ALKt may have impacted this treatment.