Apatinib Plus Sintilimab in Advanced Gastric Cancer Refractory to at Least Two Previous Chemotherapy Regimens

Inclusion Criteria:

* Age between 20-75 years old
* Has histologically confirmed diagnosis of unresectable locally advanced,recurrent or metastatic gastric or GEJ adenocarcinoma
* Life expectancy of more than 3 months
* Eastern Cooperative Oncology Group (ECOG) performance status was 0 - 1
* Have failed for at least 2 lines of chemotherapy
* At least 3 weeks from previous chemotherapy at first dose of trial drug
* Resolution of all acute toxic side effects of prior therapy or surgical procedures to grade ≤ 1 National Cancer Institute-Common Toxicity Criteria (NCI-CTC) (except for the laboratory values)
* Failure of prior palliative chemotherapy/chemotherapies (at least one irinotecan- or cisplatin-based). Failure is defined either by progression of disease or by significant toxicity that precludes further treatment.
* At least one measurable lesion defined by RECIST 1.1 as determined by investigator assessment.
* Has adequate organ function
* At least 4 weeks from any major surgery (at first dose of trial drug)
* Patients must be able to swallow apatinib

Exclusion Criteria:

* In the past, participants have received anti PD-1, anti PD-L1 or anti PD-L2 drugs or drugs targeting another stimulation or synergistic inhibition of T cell receptors (such as Cytotoxic T-Lymphocyte Antigen 4 \[CTLA-4\] and CD137)
* Other co-existing malignancies or malignancies diagnosed within the last 5 years(except cured cutaneum carcinoma or carcinoma in situs of cervix)
* Less than 4 weeks from the last clinical trial
* Active and uncontrollable bleeding from gastrointestinal tract
* Known history of QT interval prolongation, ongoing QT prolongation (\> 450 msec for males or \> 470 msec for females), any cardiac ventricular dysrhythmias, atrial fibrillation of any grade
* Hypertension that cannot be controlled by medications (\> 140/90 mmHg despite optimal medical therapy)
* Abnormal Coagulation (INR\>1.5、APTT\>1.5 UNL), with tendency of bleed;
* Factors that could have an effect on oral medication (such as inability to swallow, chronic diarrhea and intestinal obstruction);
* Active uncontrolled infection
* Known human immunodeficiency virus (HIV) infection
* Symptomatic central nervous metastasis and/or cancerous meningitis
* Known allergic/hypersensitivity reaction to any of the components of the treatment; or known drug abuse/alcohol abuse
* Pregnant or lactating women