Peripheral Blood Microarray Analysis in Pediatric Patients with Eosinophilic Esophagitis: 408

Abstract

N D A Y Peter Gann, MD, Ryan Deaton, MD, Nathan McMahon, MD, Margaret H. Collins, MD, Evan S. Dellon, MD, Ikuo Hirano, MD, Michael Grimm, MD, Amy Woo, MPH, Mahinda Karunaratne, PhD, Allan Olson, MD, Richard Aranda, MD, and Gregory J. Opiteck, PhD; Department of Pathology, University of Illinois College of Medicine, Chicago, IL, Division of Pathology and Laboratory Medicine, Cincinnati Children’s Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH, University of North Carolina, Chapel Hill, NC, Northwestern University Feinberg School of Medicine, Chicago, Celgene Corporation, Summit, NJ. RATIONALE: The HEROES study evaluated RPC4046 in adults with active eosinophilic esophagitis (EoE). In this exploratory substudy, we investigated whether RPC4046 modulates epithelial-mesenchymal transition (EMT). METHODS: Esophageal biopsy sections were taken at baseline and week 16 from 69 patients receiving weekly subcutaneous RPC4046 360 mg (n526), 180mg (n519), or placebo (n524). Slides were stained by duplex immunofluorescence for e-cadherin and vimentin, counterstained nuclei with DAPI, and scanned at 20x via multispectral digital microscopy. A machine-learning algorithm mapped each slide’s epithelial compartment. Nuclear, cytoplasmic, and membrane areas of each epithelial cell were defined and fluorescence intensity of each marker on a per-cell basis was recorded. Endpoints included change from baseline in percentage of vimentin-positive epithelial cells, change in total e-cadherin expression/ cell, and change in vimentin:e-cadherin ratio/cell. RESULTS: Change from baseline in mean percentage of vimentinpositive cells was 24.24%, 22.75%, and 20.94% for RPC4046 360 mg, 180mg, and placebo, respectively (P<0.05, 360mg vs placebo). Change in mean e-cadherin expression per cell was 101.6, 102.4, and 18.3, respectively (P<0.05, each dose group vs placebo). Change in vimentin:e-cadherin ratio was significantly different from zero for 360 mg (20.30) and 180 mg (20.18) (P<0.05). Similar effects for all markers were observed in each esophageal sampled region. CONCLUSIONS: RPC4046 significantly improved esophageal tissue EMTmarkers in patients with EoE, with a greater effect observed with 360 mg. Results support the hypothesis that prevention of IL-13 binding to receptor subtypes IL-13Ra1 and IL-13Ra2 favorably impacts inflammatory and remodeling pathways and may reduce development of esophageal fibrostenosis in EoE.