Alpelisib Plus Olaparib in Platinum-resistant/Refractory, High-grade Serous Ovarian Cancer, With no Germline BRCA Mutation Detected

Participant has histologically confirmed diagnosis of high-grade serous or high-grade endometrioid ovarian cancer, fallopian tube cancer, or primary peritoneal cancerMeasurable disease, i.e., at least one measurable lesion per RECIST 1.1 criteria (a lesion at a previously irradiated site may only be counted as a target lesion if there is clear sign of progression since the irradiation) If no measurable disease is present, the disease should be assessable by Gynecologic Cancer Intergroup criteria (GCIC) for CA-125 Participant has no germline BRCA1/2 mutation as determined by an FDA approved assay. Participant has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 Participant has platinum-resistant (progression within one to six months after completing platinum-based therapy) or platinum refractory disease (progression during treatment or within 4 weeks after the last dose), where platinum-based therapy is not an option, according to the GCIG 5th Ovarian Cancer Consensus Conference definitions. The platinum-based chemotherapy regimen does not necessarily need to be the last regimen the participant received prior to study entry. Participant must have received at least one but no more than three prior systemic treatment regimens and for whom single-agent chemotherapy is appropriate as the next line of treatment. Participant has adequate bone marrow and organ function