Systemic Immune Checkpoint Blockade and Intraperitoneal Chemo-Immunotherapy in Recurrent Ovarian Cancer

Patients will receive a total of six treatment cycles, at 3-week intervals. The study will use an IP neoadjuvant approach (IP chemoimmunotherapy of cisplatin with IP rintatolimod and IV infusion of pembrolizumab), followed by interval cytoreduction (usually laparoscopically) of residual tumor. Cytoreduction will occur approximately 4 weeks after the fourth treatment cycle. Post-surgery the investigators will consolidate with 2 additional courses of same chemo-immunotherapy regimen. Catheter will be removed 12 weeks after the last treatment. All surgical procedures, if done laparoscopically, are outpatient and will yield up to three serial biopsies of the tumor sites: 1) at catheter placement; 2) at interval cytoreduction which consists of removal of any visible tumor sites and the site biopsied initially whether tumor is present or not; 3) at catheter removal, when site of first tumor biopsy will be re-biopsied for pathologic response.