Pembrolizumab/Placebo Plus Paclitaxel With or Without Bevacizumab for Platinum-resistant Recurrent Ovarian Cancer (MK-3475-B96/KEYNOTE-B96/ENGOT-ov65).

Inclusion Criteria: * Has histologically confirmed epithelial ovarian, fallopian tube, or primary peritoneal carcinoma. * Has received 1 or 2 prior lines of systemic therapy for ovarian cancer (OC), including at least 1 prior platinum-based therapy. Participants may have received a prior poly (ADP-ribose) polymerase inhibitor (PARPi), anti-programmed cell death 1 protein (PD-1)/anti-programmed cell death ligand 1 (PD-L1) therapy, bevacizumab, or hormonal therapy; these will not be considered a separate line of therapy. Any chemotherapy regimen change due to toxicity in the absence of disease progression will be considered part of the same line of therapy. * Has provided documented informed consent for the study. * Has radiographic evidence of disease progression within 6 months (180 days) after the last dose of platinum-based chemotherapy for OC (i.e., platinum-resistant disease). * Is a candidate for paclitaxel chemotherapy (and bevacizumab, if using). * Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 assessed within 3 days before randomization. * For a female participant, she is not pregnant or breastfeeding, and at least one of the following conditions applies: Is not a woman of childbearing potential (WOCBP) OR Is a WOCBP and uses a contraceptive method that is highly effective (with a failure rate of \<1% per year). * Has radiographically evaluable disease, either measurable or nonmeasurable per Response Evaluation Criteria In Solid Tumors …