This 2 arm study will compare the efficacy and safety of treatment with erlotinib intercalated with platinum-based therapy or erlotinib along, as first line treatment in Stage IIIB/IV Non-Small Cell Lung Cancer Patients With Epidermal Growth Factor Receptor (EGFR) Mutation. Patients will be randomized to receive gemcitabine (1000mg/m2 iv) on days 1 , and cisplatin (75mg/m2) or carboplatin (5xAUC)on day 1, followed by erlotinib 150mg/day from day 15 to day 28 of each 4 week cycle for a total of 6 cycles,then followed by erlotinib monotherapy, or erlotinib 150mg/day .The anticipated time on study treatment is until disease progression, and the target sample size is 60 individuals.