Clinical benefit of readministration of gefitinib for initial gefitinib-responders with non-small cell lung cancer

Background: Gefitinib, an oral agent of epidermal growth factor receptor tyrosine kinase inhibitor, has a certain efficacy against non-small cell lung cancer (NSCLC). Several predictive factors of gefitinib sensitivity have been well described. However, few studies have investigated the clinical features of gefitinib-responders. In the present study, we analyzed the response and disease progression of primary and metastatic lesions to gefitinib in responders and the results of gefitinib readministration following temporary cessation of gefitinib upon progression of initial gefitinib treatment and other treatments. Method: We retrospectively evaluated the clinical courses of 27 NSCLC patients who received gefitinib and achieved either a complete or partial response. Results: The best-response rate and disease-control rate against the initial chemotherapy for the gefitinib-responders were 27.3% and 77.3%, respectively. Favorable efficacy was observed in the primary lesion and metastases to the lung, liver and brain, while there was no obvious effect on bone metastasis. The primary lesion and intrapulmonary metastasis were the sites of major recurrence. Median progression-free survival was 13.8 months, median duration of gefitinib treatment was 17.0 months and median overall survival was 29.2 months. Some of the patients who experienced disease progression after responding to gefitinib were again sensitive to readministration of gefitinib following temporary cessation of gefitinib and other treatments. Conclusion: Patients may still be expected to have prolonged survival if they once responded to gefitinib and then underwent various subsequent treatments followed by readministration of gefitinib. These findings might provide valuable information for the management of gefitinib-responders.