Investigation of Ubamatamab Combination Therapy in Adult Participants With Platinum-Resistant Ovarian Cancer

Multi-Arm Phase 2 Platform Study of Ubamatamab (REGN4018; MUC16×CD3 Bispecific Antibody) With or Without Additional Agents in Platinum-Resistant Ovarian Cancer

This study is researching an experimental drug called ubamatamab, also referred to as "study drug". The study is focused on participants who have advanced ovarian cancer.

The aim of the study is to see how safe, tolerable, and effective the study drug is on its own and in combination with other anti-cancer drugs (bevacizumab, cemiplimab, fianlimab, REGN10597 and a standard chemotherapy drug, pegylated liposomal doxorubicin [PLD]), referred to as "combination drugs'.

The study is looking at several other research questions, including:

• What side effects may happen from taking the study drug and its experimental combinations
• How much study drug and fianlimab is in the blood at different times
• Whether the body makes antibodies against the study drug (which could make the drug less effective or could lead to side effects) and its combinations

Key Inclusion Criteria:

1. Participants with histologically or cytologically confirmed diagnosis of advanced serous or endometrioid ovarian (regardless of the grade), primary peritoneal, or fallopian tube cancer (clear cell, mucinous, and carcinosarcoma are excluded)
2. Must have progression on prior therapy documented radiographically and must have at least 1 measurable lesion (not previously irradiated) that can be accurately measured by RECIST 1.1
3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
4. Adequate organ and bone marrow function, as described in the protocol
5. Platinum-Resistant Ovarian Cancer, as described in the protocol

Key Exclusion Criteria:

1. Major surgical procedure or significant traumatic injury within 4 weeks prior to first dose of study intervention(s)
2. Documented allergic or acute hypersensitivity reaction attributed to antibody treatments or doxorubicin hydrochloride or components of study intervention(s)
3. Another malignancy that is progressing or requires active treatment, as described in the protocol
4. Untreated or active Central Nervous System (CNS) metastases, or carcinomatous meningitis, as described in the protocol
5. Uncontrolled infections including but not limited to human immunodeficiency virus, hepatitis B or hepatitis C infection, or diagnosis of immunodeficiency
6. Moderate to large or ascites, as described in the protocol
7. Bowel obstruction within last 3 months or current need for parenteral nutrition

NOTE: Other protocol-defined inclusion/exclusion criteria apply