Inclusion Criteria:
1. Fully understand this clinical trial and voluntarily sign the written informed consent form
2. Age ≥ 18 years old
3. Histologically or cytologically confirmed high-grade serous ovarian, epithelial fallopian tube carcinoma, and primary peritoneal cancer
4. Cohort A and B：subjects with platinum-sensitive disease who have received ≤2 prior lines of systemic chemotherapy and if have a BRCAm or HRD-positive status must have recieved PARP inhibitor maintenance therapy; Cohort C: subjects with platinum-resistant disease who have received ≤3 prior lines of systemic chemotherapy
5. Disease progression or intolerability with the most recent systemic anti-tumor treatment
6. Adequate organ function with laboratory tests meeting criteria
7. Have measurable disease per RECIST v1.1
8. Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1.
9. Expected survival ≥ 3 months
10. Subjects of reproductive potential (males and females) must agree to use reliable contraceptive methods with their partner(s) throughout the trial period and for a minimum of 8 months following the last study drug administration
Exclusion Criteria:
1. Prior treatment with any topoisomerase I inhibitor-loaded ADC therapy
2. History of other malignancies within 3 years before randomization/first dose or concurrent active malignancies (except cured localized tumors such as basal cell carcinoma of the skin, squamous cell carcinoma of the skin, superficial bladder cancer, carcinoma in situ of the prostate, carcinoma in situ of the cervix, carcinoma in situ of the breast, etc., which are allowed to enroll)
3. Subjects with active central nervous system (CNS) manifestations during the screening period, CNS metastases requiring corticosteroid therapy within 28 days prior to the first study drug administration, lesions involving the brainstem, or carcinomatous meningitis.
4. Adverse reactions from prior anti-tumor therapy have not recovered to CTCAE 6.0 grade ≤ 1 (except for toxicities such as alopecia that researchers judge to have no safety risk)
5. Major surgery within 28 days before randomization/first dose, or planned to undergo systemic or local tumor resection during the study period
6. Subjects requiring folic acid supplementation during the screening period
7. Subjects who have received strong CYP3A4 inhibitors or strong CYP3A4 inducers within 14 days prior to randomization/first study drug administration, or who require continuous systemic administration of such agents during the study treatment period
8. History of severe gastrointestinal disease
9. History of severe cardiovascular disease
10. Uncontrolled serous effusions (e.g., pleural effusion, ascites, pericardial effusion) that necessitate frequent drainage or medical intervention within 14 days before randomization/first dose, or requirement for further intervention within 2 weeks after a previous intervention
11. Subjects with a history of interstitial lung disease (ILD) or non-infectious pneumonia, current non-infectious pneumonia requiring corticosteroid treatment, or suspected ILD/non-infectious pneumonia identified at screening
12. Active bacterial, fungal or viral infection within 14 days before randomization/first dose (defined as requiring intravenous anti-bacterial, anti-fungal or anti-viral drug therapy)
13. Active hepatitis B or hepatitis C, defined as HBsAg positive and HBV DNA \> 2000 IU/mL for active hepatitis B; defined as HCV-Ab positive and HCV RNA \> ULN for active hepatitis C
14. History of immunodeficiency or positive HIV antibody test during screening
15. Presence of other conditions that may interfere with participants' participation in study procedures, not in line with participants' maximum benefit from participating in the study, or affect study results: such as history of mental illness, drug abuse or substance abuse, any other clinically significant disease or condition, etc.
