Histologic or cytologic confirmed diagnosis of Stage IV NSCLC according to 2009 the seventh edition of TNM staging of lung tumors.
No disease progression after four cycles of first-line chemotherapy with gemcitabine plus cisplatin (running period) within one month before the enrollment.
Brain metastases are permitted if treated with full course of whole brain radiotherapy without the presence of symptomatic central nervous system metastases.
ECOG score 0-1
You may not be if
First-line chemotherapy other than combination treatment of gemcitabine plus cisplatin
Other therapy including targeted therapy, immunotherapy and prior radiotherapy for the treatment of the primary tumor prior to enrollment.
Active infection
Inadequate liver and renal function.
Serious concomitant systemic disorder incompatible with the study.
Second primary malignancy (except in situ carcinoma of the cervix, adequately treated basal cell carcinoma of the skin, T1 vocal cord cancer in remission, or prior malignancy treated more than 5 years prior enrollment without recurrence)
