Mirvetuximab soravtansine combined with bevacizumab or carboplatin for FRα‑positive ovarian cancer

Inclusion Criteria:

Substudy 1

* Participants must be willing to provide an archival tumor tissue block or slides or must undergo a procedure to obtain a new tumor biopsy using a low-risk, medically routine procedure for immunohistochemistry (IHC) confirmation of FRα expression as defined by the central VENTANA FOLR1 (FOLR1-2.1) assay. Tumors must have FRα-expression in \>= 50% of viable tumor cells with \>= 2+ staining intensity.
* Participants must have an Eastern Cooperative Oncology Group performance status of 0 or 1.
* 1L participants must have a confirmed diagnosis of Federation of Gynecology and Obstetrics (FIGO) Stage III or IV high-grade serous epithelial ovarian, primary peritoneal, or fallopian tube cancer.

  2L participants must have platinum-sensitive high-grade serous epithelial ovarian, primary peritoneal, or fallopian tube cancer. Participants must have platinum-sensitive disease defined as radiographic progression greater than 183 days from the last dose of most recent platinumbased chemotherapy. Note: Progression should be calculated from the date of the last administered dose of platinum therapy to the date of the radiographic imaging showing progression.
* Participant has a local homologous recombination deficient (HRD) or breast cancer susceptibility gene (BRCA) test result available. Participants with BRCA wild-type will need to have a local HRD test result available.

Substudy 2

* Participants must be willing to provide an archival tumor tissue block or slides or must undergo a procedure to obtain a new tumor biopsy using a low-risk, medically routine procedure for immunohistochemistry (IHC) confirmation of FRα expression as defined by the central VENTANA FOLR1 (FOLR1-2.1) assay. Tumors must have FRα-expression in \>= 50% of viable tumor cells with \>= 2+ staining intensity.
* Participants must have an Eastern Cooperative Oncology Group performance status of 0 or 1.
* Participants must have a confirmed diagnosis of high-grade serous ovarian, primary peritoneal, or fallopian tube cancer.
* Participants must have relapsed after 1 or 2 prior lines of platinum-based chemotherapy.
* Participants must have platinum-sensitive disease defined as radiographic progression greater than 183 days from the last dose of platinum-based chemotherapy.
* Participants must have measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 (assessed by the investigator) at baseline.

Substudy 3

* Participants must be willing to provide an archival tumor tissue block or slides or must undergo a procedure to obtain a new tumor biopsy using a low-risk, medically routine procedure for immunohistochemistry (IHC) confirmation of FRα expression as defined by the central VENTANA FOLR1 (FOLR1-2.1) assay. Tumors must have FRα-expression in \>= 50% of viable tumor cells with \>= 2+ staining intensity.
* Participants must have an Eastern Cooperative Oncology Group performance status of 0 or 1.
* Participants must have a confirmed diagnosis of high-grade serous ovarian, primary peritoneal, or fallopian tube cancer.
* Participants must have relapsed after 1 or 2 prior lines of platinum-based chemotherapy.
* Participants must have platinum-sensitive disease defined as radiographic progression greater than 183 days from the last dose of platinum-based chemotherapy.
* Participants must have measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 (assessed by the investigator) at baseline.

Exclusion Criteria:

Substudy 1

* Participants with progressive disease (PD) while on triplet therapy or after the first day of their last triplet therapy cycle and before randomization.
* Participants who receive an intervening dose of bevacizumab after the first day of their last triplet therapy cycle and before randomization.
* Participants who received prior treatment with mirvetuximab soravtansine (MIRV), any FRα-targeting agent, or Poly(ADP-ribose) polymerase inhibitor (PARPi).

Substudy 2

* More than 2 prior lines of chemotherapy. Lines of prior anticancer therapy are counted with the following considerations:

  * Neoadjuvant +/- adjuvant therapies are considered 1 line of therapy if the neoadjuvant and adjuvant correspond to 1 fully predefined regimen; otherwise, they are counted as 2 prior regimens.
  * Maintenance therapy (e.g., bevacizumab, PARPi) will be considered part of the preceding line of therapy (i.e., not counted independently).
  * If a chemotherapeutic agent in a regimen is substituted with another during a course of treatment due to toxicity, it will be considered part of the same line of therapy
  * Prior hormonal therapy will not be counted as a separate line of chemotherapy (it will be counted as part of the prior systemic therapy regimen)
* Participants who received prior treatment with mirvetuximab soravtansine or other FRα-targeting agents.

Substudy 3

* More than 2 prior lines of chemotherapy. Lines of prior anticancer therapy are counted with the following considerations:

  * Neoadjuvant +/- adjuvant therapies are considered 1 line of therapy if the neoadjuvant and adjuvant correspond to 1 fully predefined regimen; otherwise, they are counted as 2 prior regimens.
  * Maintenance therapy (e.g., bevacizumab, PARPi) will be considered part of the preceding line of therapy (i.e., not counted independently).
  * If a chemotherapeutic agent in a regimen is substituted with another during a course of treatment due to toxicity, it will be considered part of the same line of therapy
  * Prior hormonal therapy will not be counted as a separate line of chemotherapy (it will be counted as part of the prior systemic therapy regimen)
* Participants who received prior treatment with mirvetuximab soravtansine or other FRα-targeting agents.