Comparison of the Efficacy of Gefitinib in Patients with Non-Small Cell Lung Cancer according to the Type of Epidermal Growth Factor Receptor Mutation.

Background: Exon 19 deletion and L858R point mutation of the epidermal growth factor receptor (EGFR) are the most commonly encountered EGFR mutations in non-small cell lung cancer (NSCLC), and predict higher clinical outcomes following treatment with gefitinib. The objective of this study was to evaluate the differential clinical outcomes of gefitinib in patients with NSCLC according to the type of active EGFR mutation, i.e. exon 19 deletion or L858R point mutation. Methods: We identified patients with advanced NSCLC harboring the exon 19 deletion or the L858R point mutation of EGFR who were on gefitinib treatment. The clinical outcomes were evaluated. Results: Of the 124 patients with NSCLC harboring active EGFR mutations, the overall response rate, progression-free survival and overall survival were 60.5%, 11.3 and 27.3 months, respectively, and did not differ significantly between patients with the exon 19 deletion (61.8%, 11.3 and 32.2 months, respectively) and those with the L858R point mutation (58.9%, 9.0 and 27.7 months, respectively). Conclusion: It may be considered that there is no difference in the clinical efficacy of gefitinib between NSCLC patients who harbor the exon 19 deletion and those with the L858R point mutation. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]