Phase II prospective study of the efficacy of gefitinib for the treatment of stage III/IV non-small cell lung cancer with EGFR mutations, irrespective of previous chemotherapy.

Purpose: Mutations in the epidermal growth factor receptor (EGFR) gene are associated with increased sensitivity of non-small cell lung cancer (NSCLC) to gefitinib, an EGFR tyrosine kinase inhibitor. The objective of this study was to prospectively evaluate the efficacy of gefitinib in patients with stage III/IV NSCLC whose tumors carried EGFR mutations, irrespective of previous chemotherapy.

Experimental Design: Genomic DNA was extracted from tumor specimens and EGFR mutations in exons 19 and 21 analyzed by direct sequencing. Patients with stage III/IV NSCLC whose tumors had the EGFR mutations received gefitinib (250 mg/day orally). Response, toxicity and survival data were assessed.

Result: From November 2004-May 2006, 21 patients with EGFR mutations received gefitinib (median age: 59 years; 17 females; 19 non-smokers; all had adenocarcinomas). Two patients discontinued gefitinib and withdrew from the study 3 weeks after gefitinib initiation (interstitial pneumonitis, 1 patient; facial acne, 1 patient). Of 19 patients, 3 achieved complete response, 13 exhibited partial response and 3 had stable disease. Response and disease control rates were 76% (95% confidence interval [CI] 53-92) and 90% (95% CI 70-99), respectively. The most common adverse event was skin toxicity (67%); however, no grade 4 skin toxicities were seen. Ten patients relapsed and three died at a median follow-up period of 12.6 months (range 5.6-23.8 months); median progression-free survival was 12.9 months.

Conclusion: Analysis of tumor EGFR mutations in patients with NSCLC could be used to identify patients suitable for treatment with gefitinib to obtain optimum response and disease control rates.