A Study Evaluating the Efficacy and Safety of Biomarker-Driven Therapies in Patients With Persistent or Recurrent Rare Epithelial Ovarian Tumors

Inclusion Criteria: * Persistent or recurrent EOC that meets the following criteria: Histologically confirmed non-high-grade serous, non-high-grade endometrioid epithelial ovarian, fallopian tube, or primary peritoneal cancer, including but not limited to low-grade serous ovarian carcinoma, clear cell carcinoma, mucinous carcinoma, carcinosarcoma, undifferentiated carcinoma, seromucinous carcinoma, malignant Brenner tumors, Grades 1 or 2 endometrioid carcinoma, mesonephric-like adenocarcinoma and small cell carcinoma of the ovary, hypercalcemic type (SCCOHT). Disease that is not amenable to curative surgery * Measurable disease (at least one target lesion) according to RECIST v1.1 * Previous treatment with one to four lines of therapy, at least one of which was platinum-based. Hormonal therapy does not count as a line of therapy. * Platinum-resistant disease, defined as disease progression during or within 6 months of last platinum therapy, with the following exception: Participants with primary platinum-refractory disease are excluded. * Submission of a representative tumor specimen that is suitable for next-generation sequencing (NGS) testing and estrogen receptor immunohistochemistry (ER IHC) to determine treatment arm assignment and for central pathology review. * Submission of the local pathology report and, if available, any associated stained slides that supported the local diagnosis of the histology (to be used for central pathology review) * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 * Adequate hematologic and end-organ function * For women of childbearing potential: agreement to remain abstinent or use contraception, and agreement to refrain from donating eggs (if applicable) * In addition to the general inclusion criteria above, participants must meet all of the arm-specific inclusion criteria for the respective arm General Exclusion Criteria: * Pregnant or breastfeeding, or intending to become pregnant or breastfeed during the study * Primary platinum-refractory disease, defined as progression during or within 4 weeks after the last dose of the first-line platinum treatment * Histologic diagnosis of high-grade serous or high-grade endometrioid ovarian, fallopian tube, or primary peritoneal cancer * Current diagnosis of solely borderline epithelial ovarian tumor * Current diagnosis of non-epithelial ovarian tumors * Current diagnosis of synchronous primary endometrial cancer * Prior history of primary endometrial cancer, with the following exception: a prior diagnosis of primary endometrial cancer is permitted if it meets all of the following conditions: Stage IA, no lymphovascular invasion, International Federation of Gynecology and Obstetrics Grade 1 or 2, not a high-grade subtype. * Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures * Symptomatic, untreated, or actively progressing CNS metastases * Severe infection within 4 weeks prior to initiation of study treatment * Treatment with chemotherapy, radiotherapy, antibody therapy or other immunotherapy, gene therapy, vaccine therapy, or investigational therapy within 28 days prior to initiation of study treatment * Treatment with hormonal therapy within 14 days prior to initiation of study treatment * In addition to the general exclusion criteria above, participants can not meet any of the arm-specific exclusion criteria for the respective arm