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.
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.
You may not be if
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.
