Hammill, Chet W.

Abstract Background Emerging evidence suggests irreversible electroporation (IRE) with standard-of-care (SOC) chemotherapy may improve survival in patients with Stage 3 pancreatic ductal adenocarcinoma (PDAC) when compared to SOC alone. This study evaluates the overall survival (OS) and progression-free survival (PFS) of Stage 3 PDAC patients treated with SOC plus IRE with the NanoKnife System versus SOC alone. Methods This prospective, multicenter study included two cohorts from the DIRECT registry: an IRE cohort from sites offering IRE as part of clinical care, and a comparator SOC cohort of prospectively enrolled and contemporaneous retrospective patients. Enrollment spanned 08/05/2019 to 02/05/2023, with follow-up through at least 24 months, death, or loss to follow-up. Included were 137 patients (99 IRE; 38 SOC), aged ≥18 years with Stage 3 PDAC and no progression after three months of SOC therapy. Results Median (interquartile range) time from diagnosis to enrollment was 8 (6-10) months for IRE and 4 (3-6) for SOC (p<0.0001). Median OS and PSF from enrollment were 18 (95% confidence interval [CI]: 15-24) months and 9 (95% CI: 7-12) months for IRE, and 10 (95% CI: 8-14) months and 6 (5-8) months for SOC, respectively (p<0.0001 and p=0.009). Adverse events occurred in 80% (79/99) of IRE patients and 95% (36/38) of SOC patients; 29% (29/99) of the IRE cohort experiencing an IRE-related adverse event. Conclusions IRE was associated with improved OS versus SOC alone and may be an effective consolidative treatment for Stage 3 PDAC after three months of induction chemotherapy.

e16301 Background: Outcomes for patients with Stage 3 pancreatic ductal adenocarcinoma (PDAC) remain poor with a mean overall survival (OS) of 11 months. Irreversible electroporation (IRE) is a method of local tumor ablation that causes cell death by disrupting homeostasis in the cell membrane. Previous research suggests IRE can be useful in the multi-disciplinary treatment of Stage 3 PDAC. The present study was designed to assess the effectiveness and safety of IRE for Stage 3 PDAC in a real-world setting after induction chemotherapy. Methods: Patients with Stage 3 PDAC treated with IRE were prospectively enrolled in a multicenter registry study. Enrollment required 3 months of active multi-agent chemotherapy, with no progression before IRE treatment. Endpoints were 30- and 90-day mortality from enrollment and the new onset of an adverse event (AE). Results: 87 patients were enrolled in the registry between May 2019 and May 2023. Mean age was 64.0 ± 8.4 years, 57.5% were female and mean tumor diameter was 2.2 ± 0.7 cm. Mean time from diagnosis to IRE treatment was 8.9 ± 4.9 months. All subjects underwent induction chemotherapy with the most common being FOLFIRINOX alone, gemcitabine with albumin-bound paclitaxel, or a combination of both in 47 (54.0%) patients. Thirty-seven (42.5%) patients had prior radiation therapy. All procedures were performed using an open approach with 50 (57.5%) for in-situ tumor ablation and 37 (42.5%) with the intent of margin accentuation in combination with resection. Major adjunctive procedures were performed for 70 (80.5%) patients. Common adjunctive surgeries were cholecystectomy (33.3%), Whipple procedure (28.7%) and either distal or subtotal pancreatectomy (11.4%). Mean IRE delivery time was 55.7 ± 54.5 minutes with an average of 3.1 probes (range 2 to 6) used per procedure. There was a mean of 1031.1 ± 882.1 pulses delivered per procedure. The 30- and 90-day mortality was 3/87 (3.4%) and 4/82 (4.9%) respectively. There were 21 (24.1%) patients who developed AEs related to IRE treatment during the 90-day post-procedure period (9 patients had AEs that were definitely related to IRE, 5 probably and 7 possibly). Of these related events, only three were Grade 4 or higher (arterial hemorrhage, cardiac arrest, and septic shock). Overall, gastrointestinal related AEs were the most common representing 16 of the 28 (57.1%) of all AEs associated with the IRE procedure. One patient died within 30 days of the procedure due to an intraperitoneal arterial hemorrhage that was deemed to be definitely related to the IRE treatment. Conclusions: The use of IRE for curative intent tumor ablation alone or in combination with resection following induction chemotherapy in patients with locally advanced Stage 3 PDAC has acceptable safety and is associated with acceptable morbidity and mortality rates in appropriately selected patients. Clinical trial information: NCT03899649 .