Adebrelimab Combined With AG Regimen in Patients With Unresectable Locally Advanced or Metastatic Pancreatic Cancer

Inclusion Criteria: * Sign informed consent； * Aged 18-75 years (inclusive)； * Histologically or cytologically confirmed pancreatic cancer； * Unresectable locally advanced or metastatic pancreatic cancer, as determined by the investigator； * Disease progression after prior treatment with at least one systemic therapy; * No previous immunotherapy; * No previous gemcitabine-based chemotherapy; * Have at least one measurable lesion (according to RECIST 1.1 criteria); * ECOG 0\~1； * The estimated survival time is greater than 3 months; * Adequate Organ Function (within 28 days prior to first dose): Hematology: White blood cell count (WBC) ≥3.0×10⁹/L Absolute neutrophil count (ANC) ≥1.5×10⁹/L Platelets (PLT) ≥100×10⁹/L Hemoglobin (HGB) ≥90 g/L Liver Function: Aspartate aminotransferase (AST) ≤2.5×ULN Alanine aminotransferase (ALT) ≤2.5×ULN Total bilirubin (TBIL) ≤1.5×ULN Renal Function: Serum creatinine (Cr) ≤1.5×ULN or creatinine clearance (CrCl) ≥60 mL/min (calculated via Cockcroft-Gault formula). Coagulation: International normalized ratio (INR) ≤1.5 Activated partial thromboplastin time (APTT) ≤1.5×ULN Cardiac Function: No clinically significant abnormalities on electrocardiogram (ECG)； * Male subjects and females of childbearing potential must agree to use effective contraceptive measures from the first dose until 3 months after the last dose of the study drug. Exclusion Criteria: * The subject has any known active autoimmune disease; * Subjects have any complications requiring systemic treatment with corticosteroids such as prednisone (\> 10mg/ day) or have used immunosuppressive drugs within 14 days prior to initial administration; * Subjects received tumor vaccines or other immune-activating antitumor drugs (such as interferon, interleukin, thymosin, or immune cell therapy) within 1 month prior to initial administration; * Subjects are participating in another clinical trial or have received a drug intervention from another clinical trial within 4 weeks prior to the first dose; * Subjects have other malignancies requiring treatment; * Clinically significant cardiovascular disorders； * Prior allogeneic organ transplantation or hematopoietic stem cell transplantation； * Serologically confirmed HIV infection； * Active hepatitis B (HBsAg-positive with HBV-DNA ≥10³ copies/mL). Active hepatitis C (HCV antibody-positive with detectable HCV RNA and requiring antiviral therapy)； * Known hypersensitivity to monoclonal antibodies or any component of adebrelimab； * History of severe allergic reactions to gemcitabine or nab-paclitaxel； * Any situation that the investigator believes may compromise the validity of the trial or patient safety.