Inclusion Criteria:
\- Voluntary written informed consent signed prior to any study-related procedures.
Female age ≥ 18 years at the time of signing informed consent.
Histologically confirmed high-grade serous epithelial ovarian, primary peritoneal, or fallopian tube cancer.
Documented platinum-resistant recurrence, defined as progression within 6 months after completion of the last platinum-based chemotherapy regimen (excluding primary platinum-refractory disease, defined as progression during or within 3 months of first-line platinum-based therapy).
Radiologically confirmed disease progression during or following the most recent line of therapy.
FRα-positive tumor status verified by the Ventana FOLR1 (FOLR-2.1) CDx IHC assay, defined as ≥25% of tumor cells showing ≥2+ membrane staining intensity.
Presence of at least one measurable lesion according to RECIST v1.1 guidelines as evaluated by investigator imaging.
Must have received 1 to 3 prior systemic antineoplastic therapy lines.
Must have received prior treatment with bevacizumab.
Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
Adequate washout period from prior antineoplastic therapy: ≥5 half-lives or ≥4 weeks for systemic therapy (whichever is shorter); ≥2 weeks for localized palliative radiotherapy.
Recovery or stabilization of all toxicities from prior therapies to Grade ≤1 or baseline (NCI CTCAE v5.0).
Major surgery completed at least 4 weeks prior to initiation of study treatment, with postoperative toxicities recovered or stabilized.
Adequate bone marrow, hepatic, and renal organ functions.
Exclusion Criteria:
\- Non-serous histological subtypes, including endometrioid, clear cell, mucinous, sarcomatous components, mixed histology containing any of these components, or low-grade/borderline ovarian tumors.
Primary platinum-refractory disease (failure to achieve CR/PR to first-line platinum therapy or progression within 3 months after last platinum dose).
Prior wide-field radiation therapy involving ≥20% of bone marrow.
Baseline peripheral neuropathy \> Grade 1 according to CTCAE v5.0.
Active or chronic corneal disorders, history of corneal transplantation, or active ocular conditions requiring ongoing medication/monitoring (e.g., uncontrolled glaucoma, wet age-related macular degeneration requiring intravitreal injections, active diabetic macular edema, macular degeneration, papilledema, and/or monocular vision).
History of multiple sclerosis, other demyelinating diseases, or Lambert-Eaton myasthenic syndrome.
Uncontrolled severe systemic comorbid conditions (e.g., active infection, non-infectious interstitial lung disease, or clinically significant cardiovascular/cerebrovascular events within 6 months prior to first dose) rendering the patient unsuitable for the study.
History of hemorrhagic or ischemic stroke within 6 months prior to randomization/enrollment.
History of hepatic cirrhosis (Child-Pugh Class B or C).
History of bowel obstruction (including subileus) related to underlying disease within 6 months prior to study initiation.
Presence of any of the following:
History of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess;
Pelvic examination or CT scan indicating rectosigmoid/gastrointestinal involvement, or clinical signs/symptoms of intestinal obstruction.
Non-healing wounds, active ulcers, or bone fractures.
Hemoptysis (≥0.5 teaspoon / \~2.5 mL of fresh red blood per episode) within 4 weeks prior to first dose.
History of Posterior Reversible Encephalopathy Syndrome (PRES).
Clinically significant proteinuria: Urine Protein/Creatinine Ratio (UPC) ≥ 1.0 or dipstick protein ≥ 2+; if UPC ≥ 1.0 or dipstick ≥ 2+, 24-hour urine protein quantification must be ≤ 1.0 g/24h to be eligible.
History of pulmonary embolism.
History of Grade 4 thromboembolic events.
Prior treatment with mirvetuximab soravtansine, other FRα-targeting agents, or suvemcitug.
Untreated or symptomatic central nervous system (CNS) metastases.
Malignancy within 3 years prior to enrollment, except for localized cancers treated with curative intent with negligible risk of metastasis or death (e.g., adequately treated basal cell/squamous cell skin cancer or carcinoma in situ of the cervix/breast).
Pregnant or breastfeeding females.
Known hypersensitivity to any of the study intervention drugs or excipients.
Any other condition that, in the opinion of the investigator, makes the patient unsuitable for trial participation.
