This single arm study will assess the safety and efficacy of Endostar combined with chemotherapy (Gemcitabine plus Platinum-based chemotherapy) followed by Endostar maintenance therapy in patients with stage IIIB/IV non-small cell lung cancer (NSCLC).

All eligible patients will receive Endostar in combination with Gemcitabine plus Platinum-based chemotherapy for 4 cycles (21 days for each cycle). Endostar treatment will continue after completion of chemotherapy cycles until disease progression. Efficacy will be evaluated every two cycles.

Inclusion Criteria:

• Histological or cytological diagnosis of inoperable stage IIIB/IV NSCLC
• At least one measurable lesion
• Age of 18-75 years
• Life expectancy > 3 months
• ECOG performance status 0-2
• Adequate hematologic, renal, and hepatic function

Exclusion Criteria:

• Prior systemic chemotherapy for NSCLC
• Evidence of any unstable diseases (serious infection, grade 4 hypertension, unstable angina, congestive heart-failure, compromised renal or hepatic function, nonhealing wound or bone fracture)
• Concurrent anticoagulation therapy
• Evidence of bleeding diathesis or coagulopathy
• Pregnant or lactating women
• Allergic to E.coli preparation