A Study of SYS6043 in Platinum-Resistant, Advanced Ovarian, Primary Peritoneal, or Fallopian Tube Cancers

This is a randomized, open-label, multicenter Phase III clinical study designed to evaluate the efficacy and safety of SYS6043 versus investigator's choice chemotherapy in participants with platinum-resistant ovarian cancer, primary peritoneal, or fallopian tube cancer. Approximately 460 eligible participants will be enrolled in the study. Participants in the experimental group will receive SYS6043, administered on Day 1 of each cycle. Participants in the control group will receive investigator's choice chemotherapy: Liposomal doxorubicin 40 mg/m² every 28 days (Q4W), administered on Day 1 of each cycle; Paclitaxel 80 mg/m² every 28 days (Q4W), administered on Days 1, 8, 15, and 22 of each cycle; Topotecan 4 mg/m² every 28 days (Q4W), administered on Days 1, 8, and 15 of each cycle. Participants will continue to receive SYS6043 or investigator's choice chemotherapy until disease progression, unacceptable toxicity, withdrawal of consent, death, or until the Sponsor terminates the study (whichever comes first). Tumor assessments based on RECIST v1.1, including radiological assessments by CT/MRI scans will be performed at Screening and subsequently every 6 weeks (± 7 days, + 7days for the first tumor assessment after Screening) from Cycle 1 Day 1 (C1D1) for the first 36 weeks then every 12 weeks (± 7 days) until disease progression, death, the start of new anticancer therapy, or participant's withdrawal of consent (whichever occurs first). Participants who discontinue treatment prior to disease progression shall continue to undergo tumor assessment until the first occurrence of any of the following: imaging-confirmed disease progression, death, loss to follow-up, withdrawal from the trial by the participant or their legal representative, initiation of new anti-tumor therapy, or completion of the entire trial.Imaging frequency as before. All participants who discontinue SYS6043 or investigator's choice chemotherapy will be followed for survival every 2 months (± 7 days) until death, lost to follow-up, withdrawal of consent for survival follow-up, or end of study (EOS) (whichever comes first). Additional survival follow-up calls may occur periodically, if needed.