Combination of Radiation Therapy and Anti-PD-1 Antibody in Treating Patients With Pancreatic Cancer

Inclusion Criteria:

1. age:18-75 years, male or female.
2. Histologically or cytologically confirmed pancreatic cancer.
3. Measurable disease based on Response Evaluation Criteria In Solid Tumors (RECIST) 1.1.
4. Can provide either a newly obtained or archival tumor tissue sample.
5. ECOG 0-1.
6. Life expectancy of greater than 12 weeks.
7. Adequate organ function.
8. Patient has given written informed consent.

Exclusion Criteria:

1. Patients who have or are currently undergoing additional chemotherapy, radiationtherapy, targeted therapy or immunotherapy.
2. Other malignancy within 5 years prior to entry into the study, expect for curativelytreated basal cell and squamous cell carcinoma of the skin and/or curatively resectedin-situ cervical and/or breast cancers.
3. Known central nervous system (CNS) metastases.
4. Subjects with any active autoimmune disease or history of autoimmune disease.
5. Uncontrolled clinically significant heart disease, including but not limited to thefollowing: (1) > NYHA II congestive heart failure; (2) unstable angina, (3) myocardialinfarction within the past 1 year; (4) clinically significant supraventriculararrhythmia or ventricular arrhythmia requirement for treatment or intervention;
6. Active infection or an unexplained fever > 38.5°C during screening or before the firstscheduled day of dosing (subjects with tumor fever may be enrolled at the discretionof the investigator);
7. History of Interstitial Pneumonia or active non-infectious pneumonitis.
8. Known Human Immunodeficiency Virus (HIV) infection、active Hepatitis B or Hepatitis C.
9. Prior therapy with a PD-1, anti-PD-Ligand 1 (PD-L1) agent.
10. Concurrent medical condition requiring the use of cortisol (>10mg/day Prednisone orequivalent dose) or other systematic immunosuppressive medications within 14 daysbefore the study treatment. Except: inhalation or topical corticosteroids. Doses > 10mg/day prednisone or equivalent for replacement therapy.
11. Has received prior anti-cancer monoclonal antibody (mAb), chemotherapy, targeted smallmolecule therapy, or radiation therapy within 4 weeks prior to study Day 1 or notrecovered from adverse events due to a previously administered agent.
12. Received a live vaccine within 4 weeks of the first dose of study medication.
13. Pregnancy or breast feeding. Decision of unsuitableness by principal investigator orphysician-in-charge.