Abstract CT035: Addition of Salmonella-IL2 to FOLFIRINOX for metastatic stage 4 pancreatic cancer nearly doubles median survival

Introduction and Background: Salmonella-IL2 (Saltikva) is an attenuated strain of orally administered Salmonella that carries the human gene for IL-2 that colonizes the tumor microenvironment and locally releases IL-2 without any untoward effects. Following significant anti-tumor responses during preclinical study in multiple tumor models; a Phase I trial in humans found a single dose to be not toxic and elevated the Natural Killer T cell populations in patients with advanced gastrointestinal (GI) cancers. Additionally, a Phase I multiple dose trial in companion dogs with metastatic osteosarcoma demonstrated a 22% complete response rate. A Phase II trial was performed studying the addition of Salmonella-IL2 to standard of care chemotherapy for stage 4 metastatic pancreatic cancer. Patients and Methods: A Health Canada and local IRB approved, non-randomized, two-arm study in patients with Stage 4 metastatic adenocarcinoma of the pancreas is currently underway. The goal is to recruit 30 patients per arm; Arm 1: Salmonella-IL2 with FOLFIRINOX and Arm 2: Salmonella-IL2 with Gemcitabine/Abraxane. The primary outcome is overall survival with secondary outcomes of response determined by CT imaging using RECIST 1.1 criteria and biomarker data. Outcomes were compared to patients with stage 4 metastatic pancreatic cancer administered FOLFIRINOX (n=37) or Gemcitabine/Abraxane (n=24) from 4 years prior to starting this trial (2016-2020) at the study site and to historical controls from the published literature. Salmonella-IL2 is orally administered concomitantly with the administration of the prescribed chemotherapy according to arm of enrollment. 109 cfu of attenuated Salmonella-IL2 was administered orally after ingestion of a gastric acid neutralizing agent and followed with 200ml of an isotonic crystalloid fluid. Results: A total of 28 patients have been enrolled into this clinical trial. 20 patients were administered Salmonella-IL2 orally every 2 weeks with FOLFIRINOX; mean age 59.4 (32-73) years; 12(60%) women, and 8 (40%) men. 8 patients were administered Salmonella-IL2 with Gemcitabine/Abraxane every 2/3 weeks; mean age is 68.8 (56-82); 6 (66.7%) women and 3 (33.3%) men. Median survival in the FOLFIRINOX arm was 24 months compared to 11.1 months in published historical controls and 13.1 months site specific controls (n=37) (P<0.05; Log Rank Test). In addition, CT imaging using RECIST 1.1 criteria demonstrated a 73% partial response rate compared to 31% in historical controls. There have been 24 serious adverse events; none of which have been attributed to the study drug. No survival advantage was observed in the Salmonella-IL2 with Gemcitabine/Abraxane arm. Conclusion: Addition of Salmonella-IL2 to FOLFIRINOX for stage 4 metastatic pancreatic cancer results in the near doubling of median survival when compared to historical and site-specific controls receiving FOLFIRNOX only. These findings strongly indicate that a larger pivotal phase 3 multicenter trial is warranted. Citation Format: Petr Kavan, Daniel A. Saltzman, Jule Muegge, Jordan Moradian, Gerald Batist. Addition of Salmonella-IL2 to FOLFIRINOX for metastatic stage 4 pancreatic cancer nearly doubles median survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT035.