Newly Diagnosed Stage III/IV Ovarian Cancer, Neoadjuvant Carbo/Taxol/Pembro, Maintenance Olaparib/Pembro

This is a single-arm, phase II trial for patients with primary Stage III/IV advanced epithelial ovarian cancer who will receive neoadjuvant chemotherapy. All patients will receive a one-cycle lead-in of carboplatin (with or without) paclitaxel followed by three cycles of carboplatin, paclitaxel, and pembrolizumab prior to interval debulking surgery (IDS), and three cycles after IDS, followed by olaparib and pembrolizumab maintenance. Patients will receive a pre-treatment biopsy. The study will be done at 1 site and fresh tissue will be required pre-treatment as well as at the time of IDS. This tissue will be used for flow cytometry (to determine populations of cells - ie. Tregs, TILs, NK cells, MDSCs, DCs and other APCs), RNAseq (specifically looking at "hot" and "cold" signatures), proteomics (PD-L1 status and other protein expression), and immune score staining (based on the quantification of CD3 and CD8 both at the tumor center and the margins). The benefit of this study compared to other on-going upfront studies in ovarian cancer is that all patients will receive PARP inhibitor and pembrolizumab maintenance. Bevacizumab will be allowed after interval debulking surgery with the last 2 cycles of chemotherapy and can be continued as maintenance in these patients. Additionally, if a patient does not have a CR at the conclusion of their chemotherapy, bevacizumab can be added during the maintenance period.