Pressurized Intraperitoneal Aerosol Chemotherapy (Oxaliplatin) for Unresectable Colorectal Peritoneal Metastases: A Multicenter, Single-Arm, Phase II Trial (CRC-PIPAC)

Abstract

Background: Despite its increasing use, pressurized intraperitoneal aerosol chemotherapy with oxaliplatin (PIPAC-OX) has never been prospectively investigated as a palliative monotherapy for colorectal peritoneal metastases in clinical trials. This trial aimed to assess the safety (primary aim) and antitumor activity (key secondary aim) of PIPAC-OX monotherapy in patients with unresectable colorectal peritoneal metastases.

Methods: In this two-center, single-arm, phase II trial, patients with isolated unresectable colorectal peritoneal metastases in any line of palliative treatment underwent 6-weekly PIPAC-OX (92 mg/m²). Key outcomes were major treatment-related adverse events (primary outcome), minor treatment-related adverse events, hospital stay, tumor response (radiological, biochemical, pathological, ascites), progression-free survival, and overall survival.

Results: Twenty enrolled patients underwent 59 (median 3, range 1-6) PIPAC-OX procedures. Major treatment-related adverse events occurred in 3 of 20 (15%) patients after 5 of 59 (8%) procedures (abdominal pain, intraperitoneal hemorrhage, iatrogenic pneumothorax, transient liver toxicity), including one possibly treatment-related death (sepsis of unknown origin). Minor treatment-related adverse events occurred in all patients after 57 of 59 (97%) procedures, the most common being abdominal pain (all patients after 88% of procedures) and nausea (65% of patients after 39% of procedures). Median hospital stay was 1 day (range 0-3). Response rates were 0% (radiological), 50% (biochemical), 56% (pathological), and 56% (ascites). Median progression-free and overall survival were 3.5 months (interquartile range [IQR] 2.5-5.7) and 8.0 months (IQR 6.3-12.6), respectively.

Conclusions: In patients with unresectable colorectal peritoneal metastases undergoing PIPAC-OX monotherapy, some major adverse events occurred and minor adverse events were common. The clinical relevance of observed biochemical, pathological, and ascites responses remains to be determined, especially since radiological response was absent.

Trial registration: ClinicalTrials.gov NCT03246321.