King, Daniel A.

The peritoneum is the second most common site of metastasis in patients with pancreatic ductal adenocarcinoma (PDAC). Up to half of all patients that undergo curative-intent resection eventually develop peritoneal metastasis (PM), which accounts for significant morbidity and drives mortality. Despite recent advances in management, PM is associated with very poor prognosis, which is often measured in weeks to months. Clinical manifestations including bowel obstruction, ascites, and urinary obstruction have profound impact on quality of life. Even with relatively advanced disease, PM often remains occult on imaging and thus tend to be underdiagnosed and understudied. Many patients with peritoneal-only PM are excluded from clinical trials because response cannot be measured by standard radiographic criteria. Furthermore, as patients with PM are not eligible for surgical resection and low-volume peritoneal disease is often not amenable to percutaneous biopsy, tissue samples for peritoneal-specific translational studies are limited. Intraperitoneal therapeutics have been proposed as an attractive option for PM, as better penetration of tumor tissue can be achieved with less systemic toxicity compared with intravenous chemotherapy. Heated intraperitoneal chemotherapy (HIPEC), typically combined with cytoreductive surgery (CRS), is an option for select patients with PM from gynecologic or gastrointestinal primary, and for patients with primary peritoneal mesothelioma. However, the incorporation of locoregional therapy for PM in patients with PDAC has been poorly studied given the aggressive nature of pancreatic cancer and overall poor prognosis. With recent advances in existing treatment options, there may be a subset of patients who may derive benefits from locoregional control with cytoreduction and/or intraperitoneal chemotherapy. Critically, additional work is needed to determine PM-favorable clinical and tumoral predictive biomarkers to identify patients who may benefit from a more aggressive approach. We describe the current state of management of patients with peritoneal metastasis from PDAC and review the available data exploring peritoneal-directed therapy with cytoreductive surgery and/or intraperitoneal chemotherapy.

TPS4175 Background: Platinum/fluoropyrimidine (FP) with PD-1 inhibitor is now established as the standard first-line therapy for most patients with advanced HER2 negative gastric, esophageal, and gastroesophageal junction (GEJ) adenocarcinoma. The FP doublet chemotherapy backbone, most commonly FOLFOX, is recommended based on marginal survival benefits of taxane-containing triplet therapy at the cost of increased toxicity. Although several agents are approved as standard treatment options in later lines, only about 10% of patients in the US receive a third line of therapy, and very few have the opportunity to benefit from all approved agents in this disease. This challenge will only increase as more agents and targeted therapies are approved. FOLFIRINOX is a triplet regimen commonly used in gastrointestinal malignancies with established safety and often with superior efficacy. Two single arm phase II trials of FOLFIRINOX have reported promising activity in GEA with manageable toxicities. Reported median overall survival (OS) from these trials is around 15 months, which is superior to what is expected from FP doublet first-line chemotherapy (about 11 months). We hypothesize that using upfront triplet therapy with a more effective and less toxic triplet combination will result in improved patient outcomes by optimization of available therapies in GEA. Methods: This study is a randomized phase III, open-label, multicenter clinical trial with the primary objective to determine whether modified FOLFIRINOX (FU 2400 mg/m2, leucovorin 400 mg/m2, oxaliplatin 85 mg/m2, irinotecan 150 mg/m2 every 2 weeks) as first-line treatment improves OS compared to mFOLFOX in patients with advanced HER2 negative GEA. Eligible patients will have unresectable or metastatic adenocarcinoma of esophagus, GEJ, or stomach with no prior systemic treatment. Patients must have adequate organ function, and measurable or evaluable disease as defined by RECIST 1.1. Prior neoadjuvant or adjuvant therapy is allowed if completed at least 1 year prior to registration. Patients who will receive nivolumab (mandatory for PD-L1 combined positive score > 5) in addition to chemotherapy must not have any contraindications to immune checkpoint inhibitors. Patients with treated, asymptomatic and stable brain metastases are eligible. The total sample size is 382 evaluable patients for this study (191 patients per arm). The study accrual began January 2023. Clinical trial information: NCT05677490 .