Activity of a specific inhibitor, gefitinib (Iressa™, ZD1839), of epidermal growth factor receptor in refractory non-small-cell lung cancer

Background: Gefitinib (Iressa™, ZD1839) is an orally active, selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. Phase I studies showed that it is well tolerated, with evidence of tumor regression in patients with advanced non-small-cell lung cancer (NSCLC). Therefore, we aimed to assess the antitumor activity and tolerability of gefitinib in a series of patients with previously treated, advanced NSCLC, as a part of a compassionate use program. Patients and methods: To be eligible, all patients were required to have histologically or cytologically proven advanced or metastatic NSCLC, prior chemotherapy with at least one cisplatin-containing chemotherapy regimen or contraindication to cytotoxic drugs, Eastern Cooperative Oncology Group performance status ≤2, and adequate hematological, renal and hepatic parameters. All patients provided signed informed consent. Patient re-evaluation was performed every 4–6 weeks. Results: Seventy-three consecutive patients were enrolled. Response rate, including complete and partial response, was 9.6%; an additional 43.8% of patients achieved stable disease, for an overall disease control of 53.4%. EGFR1 status was evaluated by immunocytochemistry in 25 patients. According to EGFR1 immunoreactivity all responses were observed with medium/strong imunoreactivity while three out of four responses were observed in high expressive patients. Median survival for all patients was 4 months while it reached 6 months for patients with disease control. The 1-year survival rate was 13.1% for the entire series and 23.2% for patients with disease control. Non-hematological toxicity was generally mild. Conclusion: Gefitinib has promising activity with a good toxicity profile in patients with progressive NSCLC who have received one or two prior chemotherapy regimens. A possible relationship within response and EGFR1 expression is suggested.