A Clinical Study Evaluating the Safety, Tolerability, Preliminary Efficacy and Immunogenicity of a Tumor Vaccine Injection Targeting Stressinducible Proteins MICA/B in Combination With the AG Regimen in Patients With Metastatic Pancreatic Cancer

Study design: This is a single-arm, open-label, dose-escalation and dose-expansion clinical study to evaluate the safety and efficacy of multiple doses of SapDM275 tumor vaccine injection in combination with the AG regimen for the treatment of patients with metastatic pancreatic cancer who have not received prior systemic anti-cancer therapy and are planned to receive AG as first-line treatment. Treatment must be initiated within 7 days after enrollment. Patients will receive intramuscular injections of SapDM275 tumor vaccine combined with AG regimen until the occurrence of any of the following: disease progression, intolerable toxicity, death (whichever occurs first), the investigator's assessment that the subject is no longer suitable for further treatment, or withdrawal of consent by the subject.