Efficacy and Safety of BG-C9074 With Bevacizumab Compared With Bevacizumab in Adults With Ovarian, Fallopian Tube, or Primary Peritoneal Cancers

Ovarian cancer is a disease where abnormal cells in the ovaries or fallopian tubes grow out of control and form tumors. Common early signs include belly bloating, pelvic or back pain, feeling full quickly when eating, and frequent urination.

BG-C9074 is a targeted cancer medicine called an antibody-drug conjugate (ADC). ADC consists of an antibody linked to a drug that can kill cancer cells. The antibody part of BG-C9074 specifically attaches to a protein called B7-H4 that is found on the surface of cancer cells. After it attaches to B7-H4, BG-C9074 enters the cancer cell where the drug causes DNA damage and cell death. Bevacizumab is an approved medicine used to treat these cancers along with chemotherapy. It works by cutting off the blood supply that helps the tumor grow, which may help keep the cancer under better control.

The purpose of this study is to test if BG-C9074 is safe and effective in women with advanced epithelial ovarian, fallopian tube or primary peritoneal cancer when it is given in combination with bevacizumab as a first-line maintenance treatment.

This study has 2 treatment groups. Participants will be randomly assigned (by chance, like flipping a coin) to receive one of the treatments listed below:

• Arm A: BG-C9074 + Bevacizumab
• Arm B: Bevacizumab

This study will enroll approximately 600 participants. The overall time to participate in this study may be up to 5 years. Participants will make regular visits to the clinic for treatment, health checks, blood tests, and for tumor and imaging tests.

Inclusion criteria

• Able to provide a signed and dated written informed consent prior to any study-specific procedures, sampling, or data collection.
• Eastern Cooperative Oncology Group (ECOG) Performance Status ≤ 1.
• Participants must have a histologically confirmed diagnosis of epithelial high-grade ovarian, fallopian tube or primary peritoneal carcinoma (serous, endometrioid, or clear cell).
• Participants are newly diagnosed International Federation of Gynecology and Obstetrics (FIGO) stage III or IV and have received primary debulking surgery or interval debulking surgery.
• Participants must have adequate organ function.
• Women of childbearing potential must be willing to use a highly effective method of birth control and agree not to donate eggs (ova, oocytes) or freeze/store eggs for the duration of the study and for ≥ 7 months after the last dose of study treatment.

Exclusion criteria

• Participants have ovarian, fallopian tube, or peritoneal cancer of nonepithelial origin.
• Participants have either a germline or somatic BReast CAncer gene (BRCA) mutation as per local test.
• Participants who will receive poly-adenosine diphosphate ribose polymerase (PARP) inhibitor as maintenance therapy per standard of care and investigator discretion.
• Participants have a history of allergic reactions or hypersensitivity to the active ingredients and excipients of the drug products and other monoclonal antibodies.
• Participants had previous transient ischemic attack, cerebrovascular accident, or subarachnoid hemorrhage within 6 months prior to randomization
• Participants have evidence of bleeding diathesis or significant coagulopathy (in the absence of anticoagulation therapy).

Note: Other protocol defined Inclusion/Exclusion criteria may apply.