A Study of Mirvetuximab Soravtansine vs. Investigator's Choice (IC) of Chemotherapy in Platinum-Resistant, Advanced High-Grade Epithelial Ovarian, Primary Peritoneal, or Fallopian Tube Cancers With High Folate Receptor-Alpha (FRα) Expression

Inclusion Criteria:

1. Female participants ≥ 18 years of age

2. Participants must have a confirmed diagnosis of high-grade serious epithelialovarian cancer, primary peritoneal cancer, or fallopian tube cancer

3. Participants must have platinum-resistant disease:

4. Participants who have only had 1 line of platinum based therapy must havereceived at least 4 cycles of platinum, must have had a response (CR or PR) andthen progressed between >3 months and ≤ 6 months after the date of the lastdose of platinum

5. Participants who have received 2 or 3 lines of platinum therapy must haveprogressed on or within 6 months after the date of the last dose of platinumNote: Progression should be calculated from the date of the last administereddose of platinum therapy to the date of the radiographic imaging showingprogression. Note: Participants who are platinum-refractory during front-linetreatment are excluded

6. Participants must have progressed radiographically on or after their most recentline of therapy

7. Participants must be willing to provide an archival tumor tissue block or slides, orundergo procedure to obtain a new biopsy using a low risk, medically routineprocedure for immunohistochemistry (IHC) confirmation of FRα positivity

8. Participant's tumor must be positive for FRα expression as defined by the VentanaFOLR1 (FOLR-2.1) CDx assay

9. Participants must have at least one lesion that meets the definition of measurabledisease by Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1 (radiologically measured by the Investigator)

10. Participants must have received at least 1 but no more than 3 prior systemic linesof anticancer therapy, and for whom single-agent therapy is appropriate as the nextline of treatment:

11. Adjuvant ± neoadjuvant considered one line of therapy

12. Maintenance therapy (for example, bevacizumab, poly (ADP-ribose) polymerase [PARP] inhibitors) will be considered as part of the preceding line of therapy (that is, not counted independently)

13. Therapy changed due to toxicity in the absence of progression will beconsidered as part of the same line (that is, not counted independently)

14. Hormonal therapy will be counted as a separate line of therapy unless it wasgiven as maintenance

15. Participant must have an Eastern Cooperative Oncology Group Performance Status (ECOGPS) of 0 or 1

16. Time from prior therapy:

17. Systemic antineoplastic therapy (5 half-lives or 4 weeks, whichever is shorter)

18. Focal radiation completed at least 2 weeks prior to first dose of study drug

19. Participants must have stabilized or recovered (Grade 1 or baseline) from all priortherapy-related toxicities

20. Major surgery must be completed at least 4 weeks prior to first dose and haverecovered or stabilized from the side effects of prior surgery

21. Participants must have adequate hematologic, liver and kidney functions defined as:

22. Absolute neutrophil count (ANC) ≥ 1.5 x 10^9/liter (L) (1,500/microliter [μL])without granulocyte colony-stimulating factor (G-CSF) in the prior 10 days orlong-acting white blood cell (WBC) growth factors in the prior 20 days

23. Platelet count ≥ 100 x 10^9/L (100,000/μL) without platelet transfusion in theprior 10 days

24. Hemoglobin ≥ 9.0 g/dL without packed red blood cell (PRBC) transfusion in theprior 21 days

25. Serum creatinine ≤ 1.5 x upper limit of normal (ULN)

26. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3.0 x ULN

27. Serum bilirubin ≤ 1.5 x ULN (participants with documented diagnosis of Gilbertsyndrome are eligible if total bilirubin < 3.0 x ULN

28. Serum albumin ≥ 2 grams (g)/deciliter (dL)

29. Participants or their legally authorized representative must be willing and able tosign the informed consent form (ICF) and to adhere to the protocol requirements

30. Women of childbearing potential (WCBP) must agree to use highly effectivecontraceptive method(s) while on study drug and for at least 3 months after the lastdose of MIRV or at least 6 months after the last dose of paclitaxel, pegylatedliposomal doxorubicin, or topotecan

31. WCBP must have a negative pregnancy test within 4 days prior to the first dose ofstudy drug

Exclusion Criteria:

1. Participants with endometrioid, clear cell, mucinous, or sarcomatous histology,mixed tumors containing any of the above histologies, or low-grade or borderlineovarian tumor

2. Participants with primary platinum-refractory disease, defined as disease that didnot respond to (CR or PR) or has progressed within 3 months of the last dose offirst line platinum-containing chemotherapy

3. Participants with prior wide-field radiotherapy (RT) affecting at least 20% of thebone marrow

4. Participants with > Grade 1 peripheral neuropathy per Common Terminology Criteriafor Adverse Events (CTCAE) v5.0

5. Participants with active or chronic corneal disorders, history of cornealtransplantation, or active ocular conditions requiring ongoing treatment/monitoringsuch as uncontrolled glaucoma, wet age-related macular degeneration requiringintravitreal injections, active diabetic retinopathy with macular edema, maculardegeneration, presence of papilledema, and /or monocular vision

6. Participants with serious concurrent illness or clinically relevant activeinfection, including, but not limited to the following:

7. Active hepatitis B or C infection (whether or not on active antiviral therapy)

8. Human immunodeficiency virus (HIV) infection

9. Active cytomegalovirus infection

10. Any other concurrent infectious disease requiring IV antibiotics within 2 weeksbefore starting study drug Note: Testing at screening is not required for theabove infections unless clinically indicated

11. Participants with history of multiple sclerosis or other demyelinating diseaseand/or Lambert-Eaton syndrome (paraneoplastic syndrome)

12. Participants with clinically significant cardiac disease including, but not limitedto, any one of the following:

13. Myocardial infarction ≤ 6 months prior to first dose

14. Unstable angina pectoris

15. Uncontrolled congestive heart failure (New York Heart Association > class II)

16. Uncontrolled ≥ Grade 3 hypertension (per CTCAE)

17. Uncontrolled cardiac arrhythmias

18. Participants assigned to PLD stratum only: Left ventricular ejection fraction (LVEF)below the institutional limit of normal as measured by echocardiography (ECHO) ormultigated acquisition (MUGA) scan

19. Participants with a history of hemorrhagic or ischemic stroke within six monthsprior to randomization

20. Participants with a history of cirrhotic liver disease (Child-Pugh Class B or C)

21. Participants with a previous clinical diagnosis of non-infectious interstitial lungdisease (ILD), including noninfectious pneumonitis

22. Participants with required use of folate-containing supplements (for example, folatedeficiency)

23. Participants with prior hypersensitivity to monoclonal antibodies

24. Women who are pregnant or lactating

25. Participants with prior treatment with MIRV or other FRα-targeting agents

26. Participants with untreated or symptomatic central nervous system (CNS) metastases

27. Participants with a history of other malignancy within 3 years prior torandomization. Note: does not include tumors with a negligible risk for metastasisor death (for example, adequately controlled basal-cell carcinoma or squamous-cellcarcinoma of the skin, or carcinoma in situ of the cervix or breast

28. Prior known hypersensitivity reactions to study drugs and/or any of their excipients

29. People who are detained through a court or administrative decision, receivingpsychiatric care against their will, adults who are the subject of a legalprotection order (under tutorship/curatorship), people who are unable to expresstheir consent, and people who are subject to a legal guardianship order

30. Simultaneous participation in another research study, in countries or localitieswhere this is the health authority guidance