Antiangiogenesis therapy plays an important role in cancer treatment. Apatinib showed good safety and efficacy as third-line therapy for advanced gastric cancer.We conducted this trial to investigate the safety and efficacy of apatinib combined with S1 after failure of first-line chemotherapy in advanced gastric cancer or gastroesophageal junction carcinoma patients.

Inclusion Criteria:

1. Adult patients, aged between 18 and 75 years old;
2. Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2;
3. Histologically confirmed advanced or metastatic adenocarcinoma of gastric cancer(AGC) , including adenocarcinoma of the gastroesophageal junction ,one or more measurable or nonmeasurable evaluable lesions per RECIST 1.1;
4. Failure or intolerance to at least one prior line of systemic chemotherapy regimen;
5. Adequate liver, renal, heart, and bone-marrow functions ( hemoglobin≥ 80g/L, platelets ≥ 100 × 10*9/L, neutrophil ≥1.5 × 10*9/L, total bilirubin ≤1.5 ×ULN, and serum transaminase≤2.5×ULN);
6. Expected survival of ≥ 12 weeks.

Exclusion Criteria:

1. Subjects with poor-controlled arterial hypertension (systolic blood pressure> 140 mmHg and diastolic blood pressure > 90 mm Hg) despite standard medical management; Coronary heart disease greater than ClassI; I-level arrhythmia (including QT interval prolongation, for man ≥ 450 ms, for woman ≥ 470 ms) together with Class I cardiac dysfunction;
2. Subjects with high gastrointestinal bleeding risk, including the following conditions: local active ulcer lesions with positive fecal occult blood test (++); history of black stool, or vomiting blood in the past 2 months;
3. Abnormal Coagulation (INR>1.5、APTT>1.5 UNL), with tendency of bleed;
4. Factors that could have an effect on oral medication (such as inability to swallow, chronic diarrhea and intestinal obstruction);
5. Previous treatment with VEGFR inhibitor (i.e. Apatinib, sorafenib, sunitinib);
6. With psychotropic drug abuse history and can't get rid of or mental disorder patients;
7. Associated with CNS (central nervous system) metastases;
8. Active bacterial infections;
9. Pregnant or breast-feeding women;
10. Any other condition that might place the patient at undue risk or preclude a patient from completing the study.