Study to Assess the Efficacy and Safety of Rina-S Plus Standard of Care Compared to Standard of Care for Maintenance Treatment of Participants With Recurrent Platinum-sensitive Ovarian Cancer After Second-line (2L) Platinum-based Doublet Chemotherapy

This study is testing a drug called rina-S (also known as rintodestrant, an oral estrogen receptor degrader) as maintenance therapy combined with standard of care in women with ovarian, fallopian tube, or primary peritoneal cancer that has come back after initial treatment and is still sensitive to platinum-based chemotherapy. **You may be eligible if...** - You have high-grade serous or endometrioid ovarian, fallopian tube, or primary peritoneal cancer confirmed by biopsy - Your cancer came back more than 6 months after completing your first round of platinum-based chemotherapy - You have completed second-line platinum-based chemotherapy and your cancer either went away, partially shrank, or remained stable - You are being randomized within 8 weeks of your last dose of second-line chemotherapy - If your cancer has a BRCA mutation or HRD-positive status and you completed first-line treatment with a complete or partial response, you must have already received PARP inhibitor maintenance after first-line treatment **You may NOT be eligible if...** - Your cancer came back within 6 months of completing first-line platinum chemotherapy (platinum-resistant) - You have not completed the required prior treatment steps - You have significant liver, kidney, heart, or blood count abnormalities Talk to your doctor to see if this trial is right for you.