A Three-Part Phase 3 Study of Sofetabart Mipitecan in Participants With Platinum-Resistant (Part A) and Platinum-Sensitive (Parts B and C) Ovarian Cancer

Inclusion Criteria: Part A, B, and C: * Have histologically confirmed high-grade serous or endometrioid ovarian, primary peritoneal, or fallopian tube cancer. * Have confirmed availability of tumor tissue block or slides * Have radiographic progression on or after most recent line of systemic anticancer therapy * Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. * Have measurable disease per RECIST v1.1 Part A: * Have platinum-resistant disease, defined as radiographic progression less than or equal to (≤)6 months of the last administration of platinum therapy. * Have previously received 1 to 3 prior lines of systemic cytotoxic therapy. Up to 4 lines of prior cytotoxic therapy is allowed if one of those lines is mirvetuximab soravtansine. * Have received prior bevacizumab treatment, unless documented contraindication or intolerance. * Have received treatment with a poly (ADP-ribose) polymerase inhibitor (PARPi) if known to have a somatic or germline breast cancer gene (BRCA) mutation, if clinically indicated, unless documented contraindication or intolerance. Part B and C: * Have relapsed after first-line platinum-based chemotherapy and have platinum-sensitive disease defined as radiographic progression greater than (\>)6 months of their last administration of platinum therapy * Have previously received 1 to 2 prior lines of systemic cytotoxic chemotherapy Part B: \- Have previously received a PARPi, per local product label, with progression on, or within 6 months of completion of PARPi treatment. Part C: \- Have not previously received a PARPi treatment. Exclusion Criteria: Parts A, B and C: \- Have received prior antibody-drug conjugate (ADC) with a topoisomerase inhibitor payload. Part A: * Have primary platinum-refractory disease, defined as radiographic progression ≤ 1 month since the last dose of first-line platinum-containing chemotherapy. Part B and C: \- Have clinically significant proteinuria Part C: \- Have a known pathogenic BRCA1/2 gene alteration (somatic or germline).