An Open Label, Randomized, Multicenter, Phase II Study to Compare Efficacy and Safety of Gefitinib/ Pemetrexed With Pemetrexed Alone as Maintenance Therapy in Patients With Advanced (Stage IV) EGFR Mutation Negative or T790M Single Mutation Nonsquamous NSCLC Who Respond to 4 Cycles of Pemetrexed/ Platinum as First-line Therapy

The hypothesis tested in this study is that gefitinib / pemetrexed as maintenance therapy in patients with advanced (stage IV) EGFR mutation negative nonsquamous NSCLC who respond to 4 cycles of pemetrexed / cisplatin or pemetrexed/carboplatin as first-line therapy will achieve longer PFS than pemetrexed alone. We assume a median PFS of 4 months for patients receiving pemetrexed alone and the hazard ratio of pemetrexed alone compared to gefitinib/pemetrexed would be 0.42. It also indicates that the median PFS in gefitinib/pemetrexed group will be approximately 9.52 months. This is a 2-arm study in a 1:1 randomisation. Assuming an uniform accrual of 12-month with an addition of 12-month follow-up period, the total evaluable number of patients will be 52 to achieve a power of 80% and one-sided significance level of 0.025 to detect such difference between gefitinib/pemetrexed and pemetrexed alone.

Assuming 60% of patients respond (CR/PR/SD) to 4 cycles of pemetrexed/gefitinib, and among them 60% are EGFR mutation negative, 144 patients need to be enrolled to receive 4 cycles of pemetrexed/cisplatin or pemetrexed/carboplatin as first-line therapy.

Besides, the result of anaplastic lymphoma kinase gene (ALK) mutation will be retrospectively collected if the mutation is available for study patients during the study period.