Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have demonstrated good response in NSCLC harboring EGFR gene mutation. However, survival benefit from erlotinib was observed also in NSCLC patients with wild-type (wt) EGFR gene in subsets of several phase III trials. Additionally, smoking status could be a predictive factor of erlotinib efficacy. This study aimed to evaluate the efficacy of erlotinib in Japanese NSCLC patients with wt-EGFR and find a biomarker that predicts the efficacy of erlotinib other than EGFR gene mutation.Methods
The primary end point was an objective response rate. Secondary end points included disease control rate, overall survival, safety and a biomarker finding. Advanced NSCLC patients without EGFR gene mutation who had received one to three prior chemotherapy regimens and who had never smoked or light smoked (smoking index: <200) were eligible in this study. The EGFR gene status was evaluated by the PNA-LNA PCR clamp method. Erlotinib was administered daily (150 mg/day) until disease progression or unacceptable toxic effects.Results
Forty-seven patients were enrolled between March 2010 and November 2011. One patient was excluded for evaluation because having mutation of EGFR. Efficacy and safety were evaluated among 46 patients. Best responses were: PR 7 (15.2%), SD 12 (26.1%), PD 26 (46.4%), NE 1 (2.2%). Response rate and disease control rate were 15.2% (95% CI: 4.9–25.5%) and 41.3 % (95% CI 27.1–55.5%), respectively. Grade 3 or 4 adverse events were anorexia (4), skin rash (2), neutropenia (1), leukopenia (1), anemia (2), elevation of AST/ALT (1), rectal ulcer (1) and cerebral infarction (1).Two patients suffered grade 3 interstitial lung disease.Conclusion
This is the first report to evaluate Erlotinib efficacy in selected NSCLC who do not possess EGFR gene mutation. Erlotinib showed significant anti-tumor activity in pretreated never or light smoked Japanese NSCLC patients without EGFR gene mutation.