Mirvetuximab Soravtansine With Bevacizumab Versus Bevacizumab as Maintenance in Platinum-sensitive Epithelial Ovarian, Fallopian Tube, or Peritoneal Cancer

1. Adult women \>/=18 years old 2. Confirmed diagnosis of high-grade serous epithelial ovarian, primary peritoneal, or fallopian tube cancer 3. Confirmed high FRα expression by regulatory-agency approved Ventana FOLR1 (FOLR1-2.1) 4. Relapsed disease after frontline (first-line) platinum-based chemotherapy and must be plantinum-sensitive 5. Willing and able to sign the informed consent form (ICF) and adhere to protocol requirements 6. Negative pregnancy test and willing to use highly effective contraceptive method(s) while on study medication and for at least 7 months after the last dose of MIRV and 6 months after the last dose of bevacizumab

1. Endometrioid, clear cell, mucinous, or sarconmatous histology; mixed tumors containing any of the above or low grade/borderline ovarian tumor 2. More than one line of prior chemotherapy before current/planned triplet therapy 3. PD (progressive disease) while on or following platinum-based therapy 4. Prior or whole-pelvis or wide-field radiotherapy 5. \> Grade 1 peripheral neuropathy 6. History of or concurrent ocular disorders 7. Grade 4 thromboembolic events 8. Not appropriate for bevacizumab treatment 9. Requiring use of folate-containing supplements 10. Prior hypersensitivity to monoclonal antibodies 11. Pregnant or breatfeeding women 12. Received prior MIRV or other FRα-targeting agents 13. Untreated or symptomatic central nervous system metastases 14. History of other malignancy within 3 years prior to signing study consent