This study is a randomized, open-label, controlled, phase III study to evaluate the efficacy and safety of SHR-A1921 versus investigator's choice of chemotherapy in patients with platinum-resistant recurrent epithelial ovarian cancer.

Inclusion Criteria:

1. Voluntary participation and written informed consent.
2. 18 years and older, female.
3. Pathologically diagnosed epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer.
4. Patients must have platinum-resistant disease
5. Be able to provide fresh or archived tumour tissue.
6. At least one measurable lesion according to RECIST v1.1.
7. Eastern Cooperative Oncology Group (ECOG) score: 0-1.
8. With a life expectancy ≥ 12 weeks.
9. Adequate bone marrow reserve and organ function.
10. Contraception is required during the trial.

Exclusion Criteria:

1. Uncontrolled pleural effusion, pericardial effusion, or abdominal effusion with clinical symptoms.
2. Previous or co-existing malignancies.
3. Current or History of ILD.
4. Clinical symptoms or diseases of the heart that are not well controlled.
5. Arterial/venous thrombosis events occurred before the first dose.
6. Grade ≥2 bleeding events of CTCAE occurred before the first dose.
7. Gastrointestinal perforation or fistula, urethral fistula, abdominal abscess occurred before the first dose.
8. Patients with intestinal obstruction or parenteral nutrition before the first dose.
9. Serious infection before the first dose.
10. Active hepatitis B or active hepatitis C.
11. Received systemic anticancer treatments 4 weeks prior to the initiation of the study treatment.
12. Treated with TOP1 inhibitors or ADCs with TOP1 inhibitors as payload.
13. Unresolved CTCAE ≥grade 2 toxicities from previous anticancer therapy.
14. History of severe hypersensitivity reactions to either the drug substances or inactive ingredients of SHR-A1921.
15. Other inappropriate situation considered by the investigator.