This clinical trial is focused on studying treatments for persistent or recurrent rare epithelial ovarian tumors. These are specific types of ovarian cancer that have returned or continued despite treatment. The study aims to evaluate the effectiveness and safety of various treatments that are guided by specific biological markers, which are unique characteristics found in the cancer cells. The treatments being tested include several medications: Endoxan (containing cyclophosphamide monohydrate), Inavolisib (also known as GDC-0077), Giredestrant (also known as GDC-9545), Cotellic (containing cobimetinib), Ipatasertib, Lynparza (containing olaparib), Paclitaxel, Verzenios (containing abemaciclib), Kadcyla (containing trastuzumab emtansine), Avastin (containing bevacizumab), and Tecentriq (containing atezolizumab). Some participants may receive a placebo, which is a substance with no active medication.

The purpose of the study is to determine how well these treatments work in shrinking or controlling the tumors, as well as to assess their safety. Participants will receive one of the treatments based on the specific characteristics of their cancer. The study will monitor the response of the tumors to the treatment and any side effects experienced by the participants. The study is designed to last for a certain period, during which participants will have regular check-ups and tests to track their progress.

Throughout the study, participants will be closely monitored by healthcare professionals to ensure their safety and to gather information on how the treatments affect their cancer. The results of this study will help in understanding which treatments are most effective for these rare types of ovarian cancer and could lead to better treatment options in the future.