• Participants must have confirmed ovarian high-grade serous carcinoma (histologically or cytologically)

‣ Participants should have platinum resistance

⁃ No PLD use after developing platinum resistance

⁃ Participants must have had bevacizumab in a prior treatment line or must have been ineligible for bevacizumab therapy.

• ECOG status 0-1

• Measurable disease per RECIST v1.1 as assessed by local site Investigator/radiologists in the Dose Escalation phase, and assessed by BICR in the Dose Optimization phase and Phase 3; lesions situated in previous irradiated areas are considered measurable if progression has been demonstrated in such lesions

• Left ventricular ejection fraction \> 50%

• Participants with adequate hematologic function based on following

‣ Absolute neutrophil count ≥ 1.5 × 109/L

⁃ Platelet count ≥ 100 × 109/L

⁃ Hemoglobin ≥ 9.0 g/dL

⁃ Albumin ≥ 3.0 g/dL

• Adequate coagulation parameters based on the following:

‣ Prothrombin time-internationalization normal rate (INR)/partial thromboplastin time \< 1.5 × upper limit of normal (ULN)

⁃ Partial thromboplastin time or activated partial thromboplastin time \< 1.25 × ULN

• Participants must have adequate hepatic and renal function. For hepatic function, total bilirubin should be less than 1.5 times the ULN. For renal function, serum creatinine clearance must be at least 45 mL/min.

• Participants of childbearing potential (defined as sexually mature women who have not undergone surgical sterilization or been postmenopausal for at least 12 months if over 55 years of age) must have a negative pregnancy test within 72 hours before starting treatment. These participants must use highly effective contraception or abstain from heterosexual activity from screening through 120 days after the last dose of study medication.