A Study of SHR-A1904 in Previous Systemic Treatment Failed Biliary Tract Cancer

Inclusion Criteria: 1. Age 18-75 years old (including both ends), male or female; 2. ECOG-PS score: 0 or 1; 3. Expected survival ≥ 12 weeks; 4. Locally advanced or metastatic biliary tract cancer confirmed by histopathology or cytology; 5. CLDN18.2 positive expression; 6. Subjects who failed or intolerance after systemic chemotherapies; 7. According to the RECIST v1.1 standard, the subjects had at least one measurable lesion; 8. The main organ function is normal, in line with the program requirements; 9. Consent to contraception. Exclusion Criteria: 1. Received anti-tumor treatment such as chemotherapy, radiotherapy, immunotherapy, biotherapy or other clinical research drugs within 4 weeks before the first administration; 2. Other active malignancies within 5 years or at the same time; 3. Subjects with a history or evidence of brain metastasis or meningeal metastasis; 4. With acute or chronic uncontrolled pancreatitis or Child-Pugh liver function grade C; 5. Severe trauma or major surgery was performed within 4 weeks before the first administration; 6. To study the severe heart disease within 6 months before the first administration; 7. Patients with clinical symptoms and uncontrolled moderate and above pleural effusion, ascites or pericardial effusion, requiring therapeutic puncture drainage; 8. Severe infection symptoms occurred within 2 weeks before the first administration; 9. Known hereditary or acquired bleeding and thrombotic tendency; 10. Congenital or acquired immune defects; 11. The subjects had severe and uncontrollable concomitant diseases; 12. Cerebral infarction, pulmonary embolism or deep vein thrombosis occurred within 6 months before the first administration of the study.