Ovarian cancer is a lethal disease with an estimated 310,000 new cases and 200,000 deaths experienced worldwide in 2020. The purpose of this study is to assess the adverse events and change in disease activity of mirvetuximab soravtansine with carboplatin, or bevacizumab (Bev), or bev alone in participants with ovarian cancer (OC). Participants must have confirmation of folate receptor alpha (FRa) positivity by the Ventana folate receptor 1 (FOLR1) Assay. Mirvetuximab Soravtansine (MIRV) is an investigational drug for the treatment of OC. Participants will be assigned to 1 of 2 substudies and further into groups called treatment arms. In substudy 1, arms A-C, participants will receive 1 of 2 doses of MIRV with Bev, or Bev alone. In substudy 2, arms D and E, participants will receive 1 of 2 doses of MIRV with carboplatin, followed by MIRV alone. Approximately 320 participants will be enrolled in the study at 100 sites around the world. Participants will receive intravenously (IV) infused MIRV with IV infused carboplatin, or IV infused Bev, or IV infused Bev alone. The total study duration will be approximately 40 months. There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the study at a hospital or clinic and may require frequent medical assessments, blood tests, and scans.