Background: Epithelial ovarian cancer (EOC) is characterized by chemoresistant recurrences primarily confined to the intraperitoneal cavity, frequently leading to malignant small bowel obstructions. Intraperitoneal (IP) chemotherapy has been incorporated in EOC, but only in the first-line setting. Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a novel IP drug delivery method that optimizes tissue penetration depth and drug distribution, to treat recurrent peritoneal malignancies. Recent trials outside the U.S. demonstrated partial to stable response following PIPAC in recurrent EOC. To date, no clinical trials have been completed investigating the role of PIPAC in EOC in the United States. Methods: We performed a multicenter prospective phase I trial using IP cisplatin 10.5 mg/m2 and doxorubicin 2.1 mg/m2 via PIPAC at 6-week intervals. Patients were eligible if they had recurrent disease with peritoneal metastasis; extraperitoneal metastasis was allowed. The primary endpoint was dose-limiting toxicity (DLT). Secondary endpoints included progression free survival, PCI scoring, RECIST measurements, and quality of life (QoL). The patients with gastric and uterine cancers’ toxicity data were used but given inherent prognostic differences the treatment efficacy for these patients were not used in this analysis. Adverse event (AE) monitoring was graded using CTCAE spanning 18 weeks. Following completion of treatment (³2 PIPACs) patients were followed up every 12 weeks. QoL was measured using patient-reported assessments at 0, 6, 12, and 18 weeks. Baseline demographics were summarized. Mean change in PCI was calculated between cycle (C) 1 and 2, and cycle 2 and 3. Toxicities attributed to the surgery or PIPAC were reported with highest grade for each patient. Results: Nine heavily pretreated, recurrent patients were enrolled in the trial: 7 with platinum-resistant recurrent EOC, 1 with uterine cancer, and 1 with gastric cancer. PIPAC completion rate was 71.4%. Median age of participants was 65 years. Median prior lines of chemotherapy were 4 (range 2 - 10). No surgical complications occurred in the cohort. Two patients came off study: one for G3 abdominal pain and the other for G3 anorexia. For the EOC cohort, the median PCI reduction was -1.4% (C1 to C2) and -2.8% (C1 to C3). One low-grade serous EOC patient demonstrated a partial response based on RECIST criteria and received 6 cycles. Two EOC patients showed an initial response based on PCI reduction, but progressed following Cycle 2. Overall, QoL was stable. Conclusions: PIPAC with cisplatin/doxorubicin in platinum-resistant ovarian cancer is well tolerated. Intraperitoneal responses were seen in a subset of low-grade serous ovarian cancer patients, which may warrant further study. Heavily pretreated, platinum-resistant high-grade EOC patients derived limited intraperitoneal control from PIPAC monotherapy. Clinical trial information: NCT04329494.