High Efficacy of First-Line Gefitinib in Non-Asian Patients with EGFR-Mutated Lung Adenocarcinoma

Background: Several Asian studies demonstrated feasibility of front-line administration of gefitinib for the treatment of non-small cell lung carcinomas (NSCLCs) harboring intragenic epidermal growth factor receptor (EGFR) mutations. The experience of the use of this EGFR tyrosine kinase inhibitor (TKI) in non-Asian subjects remains limited. Patients and Methods: The study included lung adenocarcinoma (AC) patients treated at the N.N. Petrov Institute of Oncology (Russia). Results: DNA analysis of 192 consecutive AC revealed 38 (20%) TKI-sensitizing mutations. Presence of the exon 19 deletion (del19) or L858R was strongly correlated with nonsmoking status (smokers: 8/98 (8%); non-smokers: 30/94 (32%); p = 0.00004). The efficacy of first-line gefitinib therapy was evaluated in 25 patients with EGFR-mutated advanced AC. Twelve (48%) cases demonstrated tumor response (1 (4%) complete response, 11 (44%) partial responses; 10/17 (59%) patients with del19 mutation vs. 2/8 (25%) cases with L858R substitution, p = 0.11). The remaining 13 (52%) patients experienced disease stabilization. Median progression-free survival was 8.0 months. Grade 3 toxicity was the maximal adverse event, being observed only in 4 (16%) cases. Conclusion: Gefitinib may be considered as an upfront treatment option for EGFR-mutated NSCLC.