GOG-3068-HOTT: A Phase III Randomized Trial of Hyperthermic Intraperitoneal Chemotherapy (HIPEC) with Cisplatin Versus no HIPEC at the Time of Interval Cytoreductive Surgery Followed by Niraparib Maintenance in Patients with Newly Diagnosed Stage III and

GOG-3068-HOTT: A Phase III Randomized Trial of Hyperthermic Intraperitoneal Chemotherapy (HIPEC) with Cisplatin versus no HIPEC at the Time of Interval Cytoreductive Surgery followed by Niraparib Maintenance in Patients with Newly Diagnosed Stage III and IV Ovarian, Primary Peritoneal, and Fallopian Tube Cancer (Hyperthermic Ovarian Treatment Trial) Primary Objective: To determine if a single treatment with intraoperative HIPEC with cisplatin at the time of iCRS will result in improved PFS as compared to iCRS alone in patients with stage III or IV EOC who are treated with neoadjuvant IV platinum- based chemotherapy followed by niraparib maintenance. Secondary Objective(s): 1. To assess overall survival (OS) 2. To assess the frequency and severity of adverse events as defined by CTCAE version 5.0. 3. To assess the effect of homologous recombination repair deficiency (HRD) (yes or no), as defined by standard of care Myriad myChoiceâ HRD test, on PFS and OS. 4. To assess the effect of stage at diagnosis (III or IV) on PFS and OS. 5. To assess the effect of residual disease (no visible residual vs residual disease present) on PFS and OS. Exploratory Objective: To assess CA-125 KELIM as a predictive biomarker of response to cisplatin delivered as HIPEC or no HIPEC.