A One-Arm Exploratory Clinical Trial of Apatinib Plus Gemcitabine in Patients With Advanced Metastatic Pancreatic Cancer

Inclusion Criteria: 1. Age of patients ranges from 18 to 75 years old. 2. Histologically or cytologic confirmed advanced metastatic pancreatic cancer (Exclusion of islet cell tumor ) . 3. Must not received radiotherapy, chemotherapy or experimental treatment for advanced metastatic pancreatic cancer. Transfer of postoperative recurrence of patients with advanced pancreatic cancer can also be into the group. 4. Karnofsky Performance Status Scale (KPS) ≥70. 5. The first confirmed date of advanced metastatic pancreatic cancer not more than 6 weeks before starting treatment. 6. No jaundice symptoms. Obviously abdominal water or have symptoms, need a drainage in advance. Don't need to adjust the analgesic therapy. 7. Adequate hematologic functions :Hemoglobin (HGB) ≥ 90g/dL, Platelets (PLT) ≥ 100×10\^9/L, the absolute number of Neutrophil (ANC) ≥ 1.5×10\^9/L. 8. Adequate hepatic, renal, heart functions :Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5×the upper limit of normal (ULN).If liver metastases, AST and ALT ≤5.0×the ULN. Total bilirubin within the ULN. Serum Creatinine within the ULN, or creatinine clearance ≥ 60 mL/min. 9. Blood coagulation test results: Prothrombin Time (PT) and Partial Thromboplastin Time (PPT) within ±15% of the normal. 10. No clinically significant abnormal urine analysis results. 11. Women with pregnancy or lactation, or fertility but during treatment and 6 months after treatment of termination unwilling or unable to use effective contraception to avoid pregnancy patients with male or female 12. Signed and dated informed consent of document indicating that the patient (or legally acceptable representative) has been informed of all pertinent aspects of the trial prior to enrollment 13. Patient consent and well compliance, scheduled to accept the visits, treatment, laboratory tests and other study procedures Exclusion Criteria: 1. Patients with the known brain metastases. 2. Patients with locally advanced disease only. 3. Decline in serum albumin (ALB) ≥ 20% from the screening visit to cycle 1 day 1 prior to the 72 hours. 4. Over the past five years has a history of malignant tumors (including chronic leukemia). Patients with carcinoma in situ or basal cell carcinoma or squamous cell skin cancer can be selected. 5. With need of systemic treatment activity, unable to control bacterial, viral or fungal infections 6. Known HIV infection, or active hepatitis B or hepatitis C virus (HCV) infection. 7. A major surgery (not include the diagnostic surgery) not more than 4 weeks before starting treatment. 8. In the period of 6 months before starting treatment, Patients with myocardial infarction, severe or unstable angina, coronary artery and peripheral artery bypass grafting, New York heart association (NYHA) three - four level cardiac failure, out of control of high blood pressure, Patients with clinical significance of arrhythmia or abnormal electrocardiogram (ECG), cerebrovascular accident, transient ischemic attack, epilepsy, or with clinical significance of arrhythmia or a history of abnormal electrocardiogram (ECG). 9. Has any study drug or its accessories history of allergies or allergic reactions, or patients showed this product or controlled drug prescribing information "contraindications or special warnings and precautions" section Outlines of events. 10. The history of connective tissue disease (such as lupus, scleroderma, nodular arteritis). 11. Has a history of interstitial pneumonia, slowly progressive dyspnea and cough, sarcoidosis, and silicosis, idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, or a variety of allergies. 12. Could damage patient safety or the integrity of the data to any situation, including severe medical risk factors, medical events and laboratory abnormalities or mental illness; 13. Enter any other clinical study, some involved in drug test, or may interfere with the study in the program evaluation; 14. The patient is not willing to or cannot meet research program, or plans for vacation during the research and treatment more than 7 days or seven days; 15. The investigator think that the person doesn't fit into the study.