This is a single-center, open label, single-arm, investigator-initiated study to evaluate the efficacy and safety of XH001 (neoantigen cancer vaccine) sequential combination with immunocheckpoint inhibitor and chemotherapy in pancreatic cancer patients following surgical resection.

Inclusion Criteria:

• Provision of signed and dated informed consent form;
• Aged 18 to 75 years old;
• Histologically or cytologically confirmed diagnosis of pancreatic adenocarcinoma;
• Completed an R0 or R1 surgical resection as determined by pathology；
• Have not received any prior neoadjuvant therapy;
• ECOG score is 0 or 1;
• Life expectancy of greater than 12 months;
• CA19-9 <100U/mL before initial chemotherapy;
• Patients must have adequate organ and marrow function defined by study-specified laboratory tests prior to initial study drug.
• Woman of childbearing potential must have a negative pregnancy test and follow contraceptive guidelines as defined per protocol.

Exclusion Criteria:

• Borderline resectable pancreatic cancer;
• Evidence of disease recurrence or metastasis following surgical resection at any time;
• Evidence of malignant ascites;
• Pre-existing inflammatory bowel disease or the presence of complete or partial bowel obstruction, or persistent severe diarrhea after surgery;
• Needs to receive long-term systemic anti-allergic drug or known hypersensitivity to any component of the study treatment;
• History of autoimmune disease;
• New cerebrovascular accident (including ischemic stroke, hemorrhagic stroke, and transient ischemic attack) within 6 months before screening;
• Acute myocardial infarction within 6 months before screening, or uncontrolled angina, uncontrolled arrhythmia, severe heart failure (see Appendix 3, New York Heart Association Heart Failure Classification Criteria NYHA Class ≥ III) and other cardiovascular diseases;
• Received immunomodulatory medications within 4 weeks prior to the date of the first dose (D1) of XH001, including but not limited to: IL-2, CTLA-4 inhibitors, CD40 agonists, CD137 agonists, IFN-α;
• Received blood transfusion, erythropoietin (EPO), granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF) within 7 days prior to the first dose of XH001;
• Received therapeutic tumor vaccines;
• With congenital or acquired immunodeficiency;
• Participating in other clinical trials and had not withdrawn during screening period;
• Unable or unwilling to comply with the study protocol due to potential health, mental or social conditions in the opinion of the investigator;
• Other conditions that, in the opinion of the investigator, would make participation in this study inappropriate.