Apatinib Versus Placebo as a Third Line Treatment in Patients With Advanced or Metastatic Gastric Cancer

Inclusion Criteria: * ≥ 18 and ≤ 70 years of age * Histologically confirmed advanced or metastatic adenocarcinoma of the stomach * Have failed for 2 lines of chemotherapy * Life expectancy of more than 3 months * ECOG performance scale ≤ 2 * At least one measurable lesion (larger than 10 mm in diameter by spiral CT scan) * Duration from the last therapy is more than 6 weeks for nitroso or mitomycin * More than 4 weeks for operation or radiotherapy * More than 4 weeks for cytotoxic agents or growth inhibitors * Adequate hepatic, renal, heart, and hematologic functions (platelets \> 80 × 109/L, neutrophil \> 2.0 × 109/L, serum creatinine ≤ 1.5mg/dl, total bilirubin within upper limit of normal(ULN), and serum transaminase≤2.5×the ULN). Exclusion Criteria: * Pregnant or lactating women * History of other malignancies except cured basal cell carcinoma of skin and carcinoma in-situ of uterine cervix * Any factors that influence the usage of oral administration; Evidence of CNS metastasis * History of another malignancy within the last five years except cured basal cell carcinoma of skin and carcinoma in-situ of uterine cervix * Intercurrence with one of the following: hypertension, coronary artery disease, arrhythmia and heart failure * Receiving the therapy of thrombolysis or anticoagulation * Abuse of alcohol or drugs * Allergy to the ingredient of the agent or more than two kinds of food and drug * Less than 4 weeks from the last clinical trial * Disability of serious uncontrolled intercurrence infection.