Inclusion Criteria:
1. Patients volunteered to participate in this study and signed informed consent;
2. Age: ≥18 and ≤75 years old, male or female;
3. Advanced (metastatic or unresectable) Pancreatic ductal adenocarcinoma; and subjects must have at least one measurable lesion as defined by RECIST v1.1;
4. With failure or absence of standard treatment, and progress within 6 months of adjuvant therapy can also be included in the study;
5. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1;
6. Life expectancy ≥ 12 weeks;
7. Adequate marrow and organ function;
8. AE caused by previous anti-tumor therapy must be restored to ≤ level 1 (CTCAE v5.0) or a stable state evaluated by the researcher, except for hair loss (any level) and peripheral neuropathy of level 2;
9. Female participants of childbearing age must undergo a pregnancy test within one week before the start of the study medication, and the result is negative. They are willing to use a medically recognized and efficient contraceptive method during the study period and within three months after the last administration of the study medication; For male participants whose partners are women of childbearing age, they should agree to use effective methods of contraception during the study period and within 3 months after the last study administration;
Exclusion Criteria:
1. Known to be allergic to the investigational drug or any of its components;
2. Have other active malignancies within 5 years;
3. Systemic antitumor therapy was received 4 weeks before the start of the study, and palliative radiotherapy was completed within 14 days before the first dose;
4. Previously received allogeneic hematopoietic stem cell transplantation or organ transplantation;
5. Accompanied by untreated or active central nervous system (CNS) metastases;
6. Within 6 months prior to entering the study, patients with severe cardiovascular and cerebrovascular thromboembolism;
7. Hypertension with poor drug control (continuous increase in systolic blood pressure ≥ 150mm Hg or diastolic blood pressure ≥ 100mmHg);
8. Late stage patients with symptoms that have spread to the internal organs and are at risk of life-threatening complications in the short term;
9. With interstitial lung disease, non-infectious pneumonia, severe and uncontrolled internal medicine diseases, acute infections, recent history of major surgery (within 28 days or not yet recovered from side effects);
10. Participated in clinical trials of any drug or medical device within 4 weeks prior to the first administration;
11. With congenital or acquired immune deficiency, such as people infected with HIV, active hepatitis B (HBV DNA ≥ 500 IU/ml), hepatitis C (hepatitis C antibody positive, and HCV-RNA higher than the detection limit of the analytical method) or combined with hepatitis B and hepatitis C infection;
12. With any active autoimmune diseases or a history of autoimmune diseases;
13. Received systemic treatment with corticosteroids or other immunosuppressants within 2 weeks prior to the first medication;
14. High risk of pancreatitis, serum amylase and/or lipase concentrations ≥ 3 times ULN; who have a simple increase in lipase, will be considered for inclusion by the researchers;
15. Other situations that researchers believe should not be included.
