Phase 1 Study of Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) With Oxaliplatin. Phase 1 Study of Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) With Oxaliplatin and in Combination With Nivolumab in Patients With Peritoneal Carcinomatosis (PIANO)

Gastric cancer is the 5th most common cancer (1 million incidences per year) and the third leading cause of cancer-related mortality worldwide (740,000 deaths per year). Unresectable gastric cancer is associated with a poor 5-year survival rate (< 30%) because of its late presentation with approximately 50% of the patients diagnosed at advanced stage with a median survival of about 12 months. The treatment for advanced gastric cancer patients relies mainly on doublet or triplet chemotherapy, but results are often limited by severe side effects of the aggressive regimens. Novel efficacious treatments with reduced adverse effects are highly desirable to improve the clinical outcome.

Peritoneal disease is notoriously difficult to treat. In patients with histologically proven unresectable or recurrent gastric cancer limited to the peritoneum and/or cancer cells in peritoneal cytology, the combination of intraperitoneal (IP) paclitaxel with systemic chemotherapy seems promising. However, a phase III trial (PHOENIX-GC trial) comparing IP regimen with systemic chemotherapy versus systemic therapy alone in Japan did not show any superiority of the IP regimen.

PIPAC is an innovative intraperitoneal chemotherapy concept that enhances the efficacy by taking advantage of the physical properties of gas and pressure. This results in a superior distribution and depth of penetration of the drug. A recent systematic review of 45 clinical studies on 1810 PIPAC procedures showed response rates of 50-91% for gastric cancer (median survival of 8 to 15 months), 71-86% for colorectal cancer (median survival of 16 months).

To date, most phase II trials utilising PIPAC involve the use of cisplatin and doxorubicin or oxaliplatin. Oxaliplatin is an approved drug for systemic chemotherapy, with well documented use intraperitoneally via hyperthermic intraperitoneal chemotherapy (HIPEC) as well. This makes is a favourable agent for PIPAC in early phase studies. The dose of oxaliplatin utilised for PIPAC in the literature has thus far been arbitrarily set at 92 mg/m2, which is approximately 80% of the drug concentration used in HIPEC. Furthermore, these studies were performed on patients with a recent or concurrent administration of systemic chemotherapy, which may make interpretation of the side effects and safety profile difficult to interpret.

In Cohort 1 of this study, we intend to determine the safety profile and tolerability of PIPAC with oxaliplatin by assessment of dose limiting toxicities and the adverse event profile.