Effect of benralizumab on histopathology and inflammatory signatures in a clinical cohort of eosinophilic esophagitis

Abstract

A preliminary report from the recent phase 3 trial of benralizumab, a monoclonal antibody that binds to interleukin-5 receptor alpha (IL5Rα), in patients with EoE revealed that medication use led to tissue eosinophil eradication but did not meet the clinical endpoint of symptom resolution. Here, we characterized the clinical, endoscopic, histologic, and transcriptional changes in patients with active EoE following benralizumab treatment. We retrospectively examined patients with EoE treated with benralizumab at the University of Utah (n = 11) and reviewed reported clinical symptoms, circulating and tissue eosinophilia, and endoscopic and histologic scores. Gene expression profiles from available esophageal tissue from benralizumab-treated patients were compared to those from patients with remission EoE (n = 5), active EoE (n = 10), and controls (n = 22). Benralizumab treatment resulted in partial symptom improvement and significant reduction in tissue eosinophilia, and endoscopic and histologic disease scoring (P < 0.01). Histologic score reductions were driven by eosinophil feature scores, while scores for epithelial features (basal cell hyperplasia and dilated intercellular spaces) were similar to those in active EoE. The gene signatures in benralizumab-treated patients mimicked those of active EoE (e.g. upregulation of POSTN, CDH26, CCL26, and downregulation of DSG1). RNA profiles and pathways support histologic findings of impaired epithelial function that persists despite benralizumab treatment. In conclusion, despite eosinophil eradication, patients treated with benralizumab had persistent epithelial injury at the histologic and transcriptional level. In this cohort, benralizumab therapy failed to eradicate inflammation and epithelial dysfunction showing that interleukin-5 receptor alpha blockade monotherapy is insufficient to control EoE.

Keywords: Allergy; Histology Scoring System; IL-5 alpha receptor alpha; RNA sequencing; transcriptome.

Fig. 1

Benralizumab significantly improves eosinophilic and endoscopic response in patients with baseline active eosinophilic esophagitis (EoE). Paired before benralizumab (pre-Benra) and following benralizumab treatment (post-Benra) patient samples. (A) Peak esophageal eosinophil counts displayed in eosinophils per high power field (eos/HPF) (n=10). (B) peripheral blood eosinophil counts (k/μL) (n=10). (C) endoscopic reference scoring (EREFS) shown as a sum of each clinical endoscopy findings score (n=11). Wilcoxon matched-pairs signed rank test, mean + SEM; ^*** p<0.001, ^** p<0.01, ^*p<0.05.

Fig. 2

Benralizumab improved histologic severity and extent among treated eosinophilic esophagitis patients, but histologic improvement following benralizumab treatment was comparable to active disease. Showing composite grade and stage score, grade score closer to “1” indicates more severe EoE. Similarly, a stage score closer to “1” indicates more extensive disease. (A) Composite EoE histologic scores in paired patients before (pre) and following (post) benralizumab treatment (n=9), Wilcoxon matched-pairs signed-rank test. (B) Composite EoE histologic scores in patients before and following benralizumab treatment (n=10), with active EoE (n=10), with remission EoE (n=5), Welch’s ANOVA, mean + SD. ^**** p<0.0001, ^*** p<0.001, ^** p<0.01, ^*p<0.05, non-significant (ns).

Fig. 3

Average eosinophilic esophagitis histologic scoring system grade and stage scores for basal zone hyperplasia and dilated intercellular spaces features. Grade (severity) and stage (extent) scale is 0 to 3. (A) basal zone hyperplasia for grade and stage for patients before and following benralizumab (n=10), with active EoE (n=10) and remission EoE (n=5) (B) dilated intercellular spaces with same patient group comparison. Welch’s ANOVA, mean + SD. ^**** p<0.0001, ^*** p<0.001, ^** p<0.01, ^*p<0.05, non-significant (ns).

Fig. 4

Genes known to be associated with active eosinophilic esophagitis. Selected genes known to be associated with active EoE from prior publications with benralizumab treatment patients compared to non-EoE controls (left) and patients with active EoE compared to non-EoE controls (right). Red indicates upregulated genes in benralizumab treated or active EoE with positive log2 fold-change/fold-change and blue indicates negative log2 fold-change/fold-change.

Fig. 5

Benralizumab treated patients have up-regulated genes in inflammatory pathways and down-regulated genes in tight junction pathways despite eosinophil depletion. Gene set enrichment analysis using Hallmark gene sets from benralizumab treated compared to non-eosinophilic esophagitis (EoE) controls, EoE remission induced by diet, and Active EoE. Significant pathway differences (10% FDR) with the highest and lowest normalized enrichment score (NES) are shown.