A Study of the Treatment of Disitamab Vedotin in Patients With Locally Advanced or Metastatic Pancreatic Cancer

Inclusion Criteria: * 1\. Age: 18 (inclusive) or above, regardless of gender. * 2\. histologically or cytologically confirmed patients with locally advanced or metastatic pancreatic cancer who cannot undergo radical surgery * 3\. HER2 expressing(Immunohistochemical IHC 1+,2+ or 3+) * 4\. Number of treatment lines: Cohort 1: Prior first-line gemcitabine-free regimen or intolerant to gemcitabine-containing regimen; Cohort 2: Previous treatment with second-line standard or intolerance * 5\. Patients who have previously received neoadjuvant chemotherapy, adjuvant chemotherapy, radiotherapy or chemoradiotherapy for the purpose of curing non-metastatic disease must have a disease-free interval of 6 months from the last chemotherapy and/or radiotherapy to the random date * 6\. There is at least one measurable lesion that meets the definition of the RECIST 1.1 standard at baseline. * 7\. ECOG fitness status score: 0 or 1 point. * 8\. Estimated survival time ≥ 3 months. * 9\. Adequate organ function. * 10\. Male and female participants are eligible to participate if they agree to the contraception use as per study protocol. * 11\. Voluntary agreement to provide written informed consent. Exclusion Criteria: * 1\. Central nervous system metastasis or meningeal metastasis with clinical symptoms. * 2\. Have a history of autoimmune diseases, immunodeficiency, including HIV positive, or other acquired or congenital immunodeficiency diseases, or a history of organ transplantation. * 3\. Active hepatitis B (hepatitis B virus titer\>1000 copies/ml or 200 IU/ml); Hepatitis C virus and syphilis infection. * 4\. Have undergone major organ surgery (excluding puncture biopsy) or have experienced significant trauma within 3 weeks before the first use of the study drug. * 5\. Known hypersensitivity or intolerance to any component of the study protocol drug or its excipients. * 6\. Strong inducers and inhibitors of P-gp, a strong or moderate inducer of CYP3A4, used within 14 days prior to the first use of the study drug