An exploratory analysis of the intestinal microbiome in neoadjuvant chemotherapy for pancreatic cancer

Abstract Background: Pancreatic cancer portends a very poor prognosis. It is the third leading cause of cancer deaths in the United States. African Americans have a 50- 90% increased incidence of pancreatic cancer in comparison to other racial groups. 20% of patients with pancreatic cancer present with early stage disease and will have a median overall survival of 2.5 years if able to undergo surgical resection. There is a desperate need to discover novel ways of treating pancreatic cancer. Understanding of the microbiome may be informative to overcoming chemotherapy resistance, toxicity and improving outcomes and disparities. The aim of this study is to (1) identify changes in the intestinal microbiota during neoadjuvant treatment of pancreatic ductal adenocarcinoma that correlate with treatment response and (2) identify changes in the intestinal microbiota during neoadjuvant treatment of pancreatic ductal adenocarcinoma that correlate with treatment toxicity in a diverse patient population. Methods: Patients with resectable or borderline resectable pancreatic cancer who are enrolled in a multi-site clinical trial (NCT03483038) receiving neoadjuvant NEO-Nali-IRI (oxaliplatin, liposomal irinotecan and 5- FU) followed by surgical resection were asked to provide stool samples and a dietary log during the following four (or five) time points: baseline, mid-therapy (after C4), at completion of chemotherapy (after C8), after radiation if applicable, and at 4-6 weeks post-operative. Participants will be given stool collection kits at clinic visits for home sample acquisition. All samples will be mailed to the University of Florida Health Cancer Center Microbiome Biorepository. Data will be collected regarding demographics, stage, medical history and concurrent medications including antimicrobics and probiotics, chemotherapy dose-reductions, delays, discontinuations, adverse events, safety adverse events, attribution of causality, and hospitalizations. Outcomes will include imaging response using RECIST criteria, CA 19-9 trend, development of metastatic disease, and the ability to proceed to definitive surgical resection. DNA will be extracted from stool and analyzed using 16S rRNA sequencing methods to determine signatures and biodiversity. Descriptive statistics and correlative analysis will be reported. Continuous and categorical variables will be compared with Student’s t-test and Chi-squared test. Multiple groups will be compared by ANOVA. Kaplan-Meier logistic regression will be performed to compare outcomes between the different microbiota groupings. Conclusion: Stool collection from a multi-site clinical trial is feasible during neoadjuvant chemotherapy for pancreatic cancer and can increase diversity of the sample population. Citation Format: Sherise Rogers, Ryan Thomas, Brian Ramnaraign, Ilyas Sahin, Jesus Fabregas, Karen Russell, Steven Hughes, Ibrahim Nassour, Kathryn Hitchcock, Omar Kayaleh, Anita Turk, Ji-Hyun Lee, David DeRemer, Carmen Allegra, Thomas George. An exploratory analysis of the intestinal microbiome in neoadjuvant chemotherapy for pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B037.