Phase 1 Study of Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) and Electrostatic PIPAC (ePIPAC) With Paclitaxel for Peritoneal Carcinomatosis - PIPAC2 Study

In patients with histologically proven unresectable or recurrent gastric cancer limited to the peritoneum, the combination of intraperitoneal (IP) paclitaxel with systemic chemotherapy reported a one-year survival rate of 78%. However, the effectiveness of IP chemotherapy may be limited by its distribution, tissue penetration and associated catheter-related complications.

Pressurized Intra-Peritoneal Aerosol Chemotherapy (PIPAC) is a novel drug delivery technique for PC taking advantage of physical laws (gaseous nature, hydrostatic pressure) with superior pharmacological properties (homogeneous distribution, deeper tissue penetration). It is applied through laparoscopy and is minimally invasive. Adding electrostatic loading (ePIPAC) as an adjunct would further improve the pharmacological properties of PIPAC since it should induce precipitation of the aerosolized drug, increasing the ratio between the dose applied and the dose in the target tissue.

Systemic toxicity is significantly reduced due to the peritoneum/blood barrier and the low dose applied (about 20% of the usual systemic dose). A systematic review highlighted that PIPAC combines the benefits of a minimally invasive approach with pharmacokinetic advantages of intraperitoneal administration and pressurized vaporization. It concluded that PIPAC is feasible, safe, and warrants further prospective studies. PIPAC may be combined with systemic palliative chemotherapy with minimal additional organ toxicity. This method of treatment avoids the morbidity and mortality of HIPEC. PIPAC has been shown in pre-clinical studies to be potentially more efficacious than catheter-based IP-chemotherapy due to better drug distribution and penetration. In clinical use, PIPAC can be repeated at intervals of 6 weeks to 3 months. This allows repeated objective assessment of therapy effect over time.

To date, PIPAC has only been utilized to administer Oxaliplatin or a combination of Doxorubicin/Cisplatin. Paclitaxel is an approved drug for systemic chemotherapy for several cancers, and also has well-documented intraperitoneal use for ovarian cancer and gastric cancer. It is a hydrophobic, high molecular weight compound resulting in low absorption through the lymphatic system after IP administration with a much higher peritoneal to plasma peak concentration and AUC ratios (>1000 versus 25 and >1000 versus 16 respectively). As such, IP Paclitaxel may be potentially more efficacious with less systemic toxicity than IP Oxaliplatin. However, no clinical data exists in the published literature for PIPAC/ePIPAC paclitaxel.

This proposed prospective study is the first clinical study of PIPAC/ePIPAC with Paclitaxel. It will determine the maximal tolerated dose (MTD) and evaluate the safety and tolerability, and pharmacokinetics of PIPAC/ePIPAC paclitaxel in pre-treated patients with PC. Peritoneal biopsies will be collected prior to and after PIPAC/ePIPAC to assess tissue drug concentration and depth of drug penetration. Collection of biospecimens including peritoneal tissue, peritoneal fluid and blood will be used for correlative studies including paclitaxel resistance analysis and development of cancer modelling platforms. For the individual patient, repeated biopsies and molecular profiling may also facilitate individualized therapy. For medical research, PIPAC/ePIPAC may deliver measurable progress in 3-5 years because the assessment interval is short (6 weeks) in this disease with rapid progression (6-12 months to death).