This study is a randomized, open-label, controlled, phase III study to evaluate the efficacy and safety of HS-20089 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 tumor 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. Prior treated with TOP1 inhibitors or ADCs with TOP1 inhibitors as payload.
2. Previous or co-existing malignancies.
3. Uncontrolled pleural effusion, pericardial effusion, or abdominal effusion requiring clinical intervention.
4. Received systemic anticancer treatments 4 weeks prior to the initiation of the study treatment.
5. Unresolved CTCAE ≥grade 2 toxicities from previous anticancer therapy.
6. History of severe hypersensitivity reactions to either the drug substances or inactive ingredients of HS-20089.
7. Any serious or uncontrolled medical disorder in the opinion of the investigator that may increase the risk associated with the study participation or study drug administration.
8. Other inappropriate situation considered by the investigator.