Phase I/II study of oxaliplatin dose escalation via a laparoscopic approach using pressurized aerosol intraperitoneal chemotherapy (PIPOX trial) for nonresectable peritoneal metastases of digestive cancers (stomach, small bowel and colorectal): Rationale and design

Background: The annual incidence of gastrointestinal carcinomas (stomach, small bowel, colon and rectum) is increasing in Western countries, reaching 50,000 new cases each year in France. Peritoneal carcinomatosis (PC) is diagnosed in 15% of these patients. Complete cytoreductive surgery (CCS) plus Hyperthermic IntraPeritoneal Chemotherapy (HIPEC) is the only therapy that can offer patients with PC a chance for long-term survival with a 5 year overall survival (OS) rate of 30-60% versus 0-5% with systemic chemotherapy alone. However, CCS plus HIPEC still presents serious limitations and very few patients (10%) are candidates for these radical treatments. PC remains a palliative setting for 90% of patients with a median survival ranging from 15 to 25 months. Innovative surgical therapies such as Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) therefore need to be developed to improve the prognosis. Potential benefits were obtained after intraperitoneal nebulization of oxaliplatin in patients with advanced PC from colorectal cancer. Innovative surgical therapies such as pressurized intraperitoneal aerosol chemotherapy (PIPAC) have been proposed as palliative locoregional treatment with some promising results. The dose of oxaliplatin currently established by nebulization (PIPAC) is really low at 92 mg/m². However, the peritoneum acts as a barrier limiting the systemic passage of intraperitoneal drug. Oxaliplatin used at higher doses during PIPAC procedures could be a safe option and allow better intratumoral penetration of chemotherapy.

Method and design: The proposed study is a multicenter phase I/II trial of oxaliplatin dose escalation during PIPAC. The aim is to determine the maximum tolerated dose of pressurized oxaliplatin administered by the intraperitoneal route (PIPAC) during two consecutive procedures at a 4-6 week interval for patients with extended peritoneal carcinomatosis from the gastrointestinal tract. Dose started at 90 mg/m² and escalation was in 50 mg/m² steps up to a maximum of 300 mg/m².

Discussion: Oxaliplatin is an effective drug in gastrointestinal cancer and high doses given by the intraperitoneal route during HIPEC are well tolerated. In this phase I trial, we hypothesized that high-dose oxaliplatin during PIPAC is feasible and safe. The repeated local administration of high doses of oxaliplatin could improve tumor response and prognosis.

Trial registration: Prospective study. ClinicalTrials.gov: NCT03294252. EudraCT: 2016-003666-49.