include but are not limited to the following: - Has diagnosis of FIGO 2014 Stage III or Stage IV, histologically confirmed epithelial ovarian, primary peritoneal, or fallopian tube carcinoma with one of the following histologies: high-grade serous, high-grade endometrioid, clear cell carcinoma, or malignant mixed Müllerian tumour with a high-grade serous component. Tumors reported as Grade 2 may be enrolled only if predominately (>50%) Grade 3 features are present. - Has completed primary debulking surgery or interval debulking surgery. - Has completed first-line (1L) platinum-based chemotherapy, with a response of stable disease, partial response, complete response or no evidence of disease per protocol. - Has provided tumor tissue that is not previously irradiated. - Has well-controlled human immunodeficiency virus (HIV) on antiretroviral therapy if diagnosed with HIV - Has undetectable hepatitis B virus (HBV) viral load and received HBV antiviral therapy if hepatitis B surface antigen (HBsAg)-positive. - Has undetectable hepatitis C virus (HCV) viral load if has a history of HCV infection. The main

include but are not limited to the following: - Has nonepithelial cancers, low-grade serous tumors, low-grade endometrioid tumors, borderline tumors mucinous, seromucinous that is predominantly mucinous, malignant Brenner's tumor, and undifferentiated carcinoma. - Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis. - Has a history of severe eye disease. - Has active inflammatory bowel disease requiring immunosuppressive medication or a previous history of inflammatory bowel disease. - Has uncontrolled, significant cardiovascular disease or cerebrovascular disease. - Has a history of (noninfectious) pneumonitis/interstitial lung disease (ILD), which required steroids, has current pneumonitis/ILD, or has suspected ILD, or pneumonitis that cannot be ruled out by standard diagnostic assessments at Screening. - Received prior systemic anticancer therapy, with the exception of the first-line platinum-based chemotherapy required by the inclusion criteria. - Had a live or live-attenuated vaccine within 30 days of randomization. - Has a known additional malignancy that is progressing or required active treatment within the past 3 years. - Has active infection requiring systemic therapy. - Has concurrent and active HBV and HCV infections. - Has HIV infection and a history of Kaposi's sarcoma and/or multicentric Castleman's disease. - Has not recovered from major surgery or has ongoing surgical complications. - Has a homologous recombination deficiency (HRD)-positive, unknown, or inconclusive tumor status as determined by the central laboratory. - Active or ongoing stomatitis of any grade.