This study was undertaken to investigate the efficacy and the feasibility of gefitinib for chemotherapy-naïve patients with advanced non–small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations.

The EGFR gene status in various tumor samples obtained from chemotherapy-naïve advanced NSCLC patients was examined by DNA sequencing of EGFR exons 18 to 23. Patients harboring EGFR mutations received gefitinib (250 mg/d) alone. The response rate, progression-free survival (PFS), and toxicity profile were assessed prospectively.

Between June 2004 and October 2005, 75 patients were examined for the EGFR status, and 25 patients (33%) harbored EGFR mutations. EGFR mutations were significantly frequent in females (P < .01) and never or light smokers (P < .001). Sixteen patients with EGFR mutations were enrolled onto the study. The overall response rate in these patients was 75% (95% CI, 54% to 96%), and the disease control rate was 88% (95% CI, 71% to 100%). The median PFS time of these patients was 9.7 months (95% CI, 7.4 to 9.9 months). No life-threatening toxicity was observed.

Treatment with gefitinib alone for chemotherapy-naïve NSCLC patients with EGFR mutations could achieve a high efficacy with acceptable toxicity. To assess the proper timing of gefitinib in such patients, a subsequent randomized trial comparing gefitinib with standard chemotherapy is warranted.