This is a multicenter, prospective, open-label Phase II clinical study designed to evaluate the efficacy and safety of sacituzumab govitecan monotherapy in patients with locally advanced or metastatic pancreatic ductal adenocarcinoma who have failed at least one prior line of therapy, and to explore the potential correlation between baseline tumor tissue TROP-2 expression and treatment efficacy. The study plans to enroll 30 eligible subjects, who will receive sacituzumab govitecan at 5 mg/kg via intravenous infusion every 2 weeks as one treatment cycle, until disease progression or intolerable toxicity occurs. The primary endpoint is Objective Response Rate (ORR); secondary endpoints include Progression-Free Survival (PFS), Overall Survival (OS), Disease Control Rate (DCR), Duration of Response (DOR), and the incidence and severity of Treatment-Related Adverse Events (TRAEs).

Inclusion Criteria:

1. Voluntary participation with written informed consent provided
2. Age ≥18 years at the time of signing the informed consent form
3. Histologically or cytologically confirmed pancreatic ductal adenocarcinoma (including adenosquamous carcinoma)
4. Failure of or disease progression after at least one prior line of systemic therapy for locally advanced or metastatic pancreatic cancer
5. At least one measurable target lesion at baseline per RECIST 1.1 criteria (a single measurable lesion must not have received prior radiotherapy, or must have demonstrated clear progression after radiotherapy)
6. ECOG performance status score of 0-2
7. Adequate organ and bone marrow function (including hematologic, hepatic, renal, and coagulation parameters meeting specified criteria)
8. Subjects of childbearing potential must use highly effective contraception, and female subjects must have a negative pregnancy test
9. Ability and willingness to comply with study-related procedures.

Exclusion Criteria:

1. History of or current presence of central nervous system metastases
2. Presence of untreated or unstable spinal cord compression
3. High risk of gastrointestinal or intra-abdominal bleeding
4. Prior treatment with TROP2-targeted agents or antibody-drug conjugates (ADCs)
5. Requirement for strong CYP3A4 inhibitors or inducers within 2 weeks prior to the first dose, or inability to avoid their use during the study
6. History of severe dry eye syndrome, meibomian gland disease, or other corneal disorders that may impair corneal healing
7. Major surgery within 28 days prior to the first dose (excluding palliative procedures), or receipt of curative radiotherapy within 3 months
8. Presence of other malignancies within 3 years prior to the first treatment (except for certain definitively treated cancers)
9. Uncontrolled severe systemic diseases such as cardiovascular or cerebrovascular disease, diabetes mellitus, or hypertension
10. History of interstitial lung disease or non-infectious pneumonitis, or current related lesions
11. Presence of severe underlying pulmonary disease, autoimmune disease, or prior total pneumonectomy
12. Active chronic inflammatory bowel disease, gastrointestinal obstruction, or other severe gastrointestinal disorders
13. Tumor invasion of critical organs or vessels with associated symptoms, or risk of fistula formation
14. Toxicities from prior antitumor therapy not recovered to ≤ Grade 1 (except for low-risk toxicities)
15. Active hepatitis B, hepatitis C, HIV infection, or active syphilis
16. Known allergy to the investigational drug or its components, or history of severe hypersensitivity to other biologic agents
17. Severe infection within 4 weeks prior to dosing, or active infection requiring systemic therapy within 2 weeks
18. Receipt of non-specific immunomodulatory therapy or antitumor traditional Chinese medicine within 2 weeks prior to dosing
19. Receipt of live vaccines within 30 days prior to dosing or planned during the study period
20. Pregnant or breastfeeding women, or individuals of childbearing potential who are not using highly effective contraception as required
21. Individuals considered vulnerable populations (e.g., patients with psychiatric disorders or critically ill patients), or any other condition deemed unsuitable for enrollment by the investigator.