Plasma metabolomics to predict chemotherapy (CTX) response in advanced pancreatic cancer (PC) patients (pts) on enteral feeding for cachexia.

Abstract

600 Background: We evaluated the potential of plasma metabolites as predictors of response to CTX in a prospective cohort of pts who received enteral feeding for cachexia and advanced PC. Methods: The PANCAX-1 (NCT02400398) prospective trial enrolled 31 cachectic advanced PC pts to receive jejunal tube peptide-based diet for 12 weeks (wks) who were planned for palliative CTX. Out of 16 evaluable pts, 62.5% receiving enteral feeding met the primary endpoint of weight stability at 12 wks. As part of an exploratory analysis of the PANCAX-1 trial, serial blood samples were collected at 3 predefined timepoints over 12 wks of enteral feeding. Up to 219 plasma metabolites were analyzed by mass spectrometry and high-performance liquid chromatography. Analytes were compared by relative area under the curve (AUC) and differences evaluated by two-sample t-tests. The mean AUC was used in pts with metabolites measured from > 1 timepoint of collection. Pts were stratified by stable disease (SD), partial response (PR), or progressive disease (PD) as best overall response to standard CTX. Results: Of 31 pts with advanced PC prospectively enrolled for enteral feeding, there were 55 blood samples collected from 28 pts available for plasma metabolomics. 20/28 (71%) pts received first-line CTX, the majority of whom (90%) received gemcitabine-based CTX. There were 2 PRs (7%) and 10 with SD (36%) as best response to CTX. Overall, there were statistically significant differences in levels of intermediates involved in multiple metabolic pathways including glycolysis, the tricarboxylic acid (TCA) cycle, fatty acid synthesis, and nucleoside synthesis in pts with PR/SD vs. PD to CTX (all p < 0.05). When stratified by CTX regimen, PD to 5-fluorouracil-based CTX (e.g., FOLFIRINOX) was associated with decreased levels of essential amino acids (AAs, L-leucine, L-methionine, L-tryptophan) and non-essential AAs (L-arginine, L-serine, L-tyrosine, all p < 0.05). For gemcitabine-based CTX (e.g., gemcitabine/nab-paclitaxel), PD was associated with increased levels of intermediates of glycolysis (pyruvate), TCA cycle (L-glutamate), nucleoside synthesis (xanthine), and bile acid metabolism (taurocholic acid, all p < 0.05). Conclusions: We are the first to demonstrate the feasibility of plasma metabolomics in a prospective cohort of advanced PC pts on enteral feeding as their primary source of nutrition. Metabolic signatures unique to FOLFIRINOX or gemcitabine/nab-paclitaxel may be predictive of response and warrant further study.