This is a phase 2 clinical study,to explore the efficacy and safety of Disitamab Vedotin in patients with locally advanced or metastatic pancreatic cancer expressing HER2.

63 patients with locally advanced or metastatic pancreatic cancer will participate in this study. HER2 expression in locally advanced or metastatic pancreatic cancer patients is defined as the expression of HER2 in tumor tissues detected by immunohistochemistry (IHC) as IHC 1+, 2+, or 3+. The arm 1 recruits 43 patients and the arm 2 recruits 20 patients.

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