Combination of Anti-PD-1 Antibody and Chemotherapy in Metastatic Pancreatic Cancer

Inclusion Criteria:

* •Pathologically (histologically or cytologically) confirmed pancreatic ductal adenocarcinoma (PDAC).

  * Recurrent disease or metastatic disease (such as liver, peritoneum, lung) evaluated by abdominal contrast-enhanced CT, MRI, and chest CT. PET/CT or other imaging examinations would be used if necessary.
  * Never receive any systematic treatment or Progression after fisrt line Gemcitabine base chemotherapy
  * ECOG score 0 or 1.
  * Serum creatinine level is normal, and serum total bilirubin level is less than 1.5 x ULN.
  * ALT and AST are less than 2 x ULN.
  * Signed informed consent.

Exclusion Criteria:

* •History of participation of other clinical trails within 4 weeks

  * History of autoimmune disease or other condition receiving glucocorticoid treatment
  * History of receiving chemotherapy within 2 weeks
  * History of radiotherapy and molecular target therapy within 2 weeks
  * History if active tuberculosis
  * History of malignance treatment in the past, excluding basal and cutaneous squamous cell carcinoma, cervical carcinoma in situ, papillary thyroid carcinoma
  * Major cardiovascular diseases (including myocardial infarction, unstable angina, congestive heart failure, severe uncontrolled arrhythmia) during the past six months of enrollment.
  * Hematological precancerous diseases, such as myelodysplastic syndromes.
  * Evidence of clinical-related or previous interstitial lung disease, such as noninfectious pneumonia or pulmonary fibrosis, or baseline chest CT scan or chest X-ray findings
  * Previous or physical findings of central nervous system disease, except for adequately treated (e.g. primary brain tumors, uncontrolled seizures or strokes with standard medications)
  * Preexisting neuropathy \> 1 (NCI CTCAE).
  * Immune deficiency syndrome, such as active tuberculosis and HIV infection.
  * Allograft requires immunosuppressive therapy or other major immunosuppressive therapies.
  * Severe serious wounds, ulcers or fractures.
  * Clinical evaluation is unacceptable