Purpose: To evaluate the efficacy of single-agent gefitinib (Iressa, ZD1839), an oral, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, as first-line compassionate use therapy for advanced non-small-cell lung cancer (NSCLC). Patients and methods: Twenty-five patients who were unfit or refused chemotherapy received oral gefitinib 250 mg daily as first-line therapy for the treatment of recurrent or metastatic NSCLC in a compassionate use program at a single institution. Results: Four of 22 evaluable patients (18%), two with adenocarcinomas and two with bronchioloalveolar carcinomas, had an objective response and five patients (23%) had stable disease. Duration of response or stable disease was 3.5-22+ months. Median time to progression was 2.2 months, median survival was 12.6 months and 1-year survival 52%. The partial response plus stable disease rate by Eastern Cooperative Oncology Group (ECOG) performance status (PS) was 4/5 for PS 0 patients; 3/6 for PS 1-2 patients; and 2/14 for PS 3-4 patients. The two patients with PS > 2 who derived benefit from gefitinib had PS 3 due to co-morbidities. Two patients discontinued therapy due to severe toxicities: one patient had severe liver dysfunction and hemorrhagic cystitis, and another patient developed diarrhea with hypotension. A correlation between rash and antitumor activity was noted. Of seven patients who received chemotherapy subsequent to gefitinib, one had a partial response, three had stable disease, two progressed, and one was non-evaluable for response. Conclusion: We report encouraging response and survival results with gefitinib as first-Line treatment in unsetected patients with advanced NSCLC. Gefitinib monotherapy should undergo further evaluation as first-tine therapy in advanced NSCLC. (C) 2003 Elsevier Ireland Ltd. All rights reserved.