The Continuation of Gefitinib Treatment Beyond Progression in Non-small Cell Lung Cancer Patients With EGFR Mutation

Although EGFR-TKIs such as gefitinib, erlotinib or afatinib are recommended as first-line therapy in patients with advanced, recurrent or metastatic nonsquamous NSCLC patients who have known active EGFR mutation and achieved response to EGFR TKIs experience disease progression eventually with 10-14 moths of median progression free survival.6 Platinum-doublets combination chemotherapy remains standard of care for patients with progressive disease. However, patients may derive benefit from EGFR TKIs after RECIST-assessed progression especially for those who experience slow progression. And previous report suggested that premature discontinuation of EGFR TKIs has resulted in rapid progression in symptoms and tumor growth.7 Recently, a prospective phase II single arm study in Asian patients with EGFR mutation-positive NSCLC to determine the continuation of erlotinib beyond progression judged by investigators showed that additional PFS of 3.1 months can be achieved with continuation of erlotinib without serious additional toxicities.8 Until now, no prospective study has been conducted for gefitinib.

In this study the continuation of gefitinib beyond RECIST progression will be investigated to determine the clinical outcomes including the duration of treatment and safety.

This is a single-arm phase II trial to evaluate the efficacy and safety of continuation of gefitinib in EGFR mutant NSCLC patients who experience RECIST progression. Based on the results of "ASPIRATION" study, the median PFS for continuation of gefitinib will be around 3 months. The study treatment will be of no interest if the true median PFS is 2.5 months or shorter. In contrast, it will be of interest if the true median PFS is 3.5 months or longer. Considering 1 sided alpha of 0.05 and 90% of power, 95 patients are required. A total of 100 patients will be needed considering 5% of drop-out rate. 6 months of accrual and additional 6 months of follow-up will be assumed for this study.

Patients will be treated 250 mg/day of gefitinib orally (1 cycle for 28 days). Cycles were repeated until disease progression, unacceptable toxicity, or until the patient or the investigator requested therapy discontinuation.