Long-term Continued Proton Pump Inhibitor Use is Common in Patients Diagnosed with Eosinophilic Esophagitis Despite Failure of Histologic Response: Data from a two-centre study: Long-term PPI Use in Patients with EoE

Review article: Emerging insights into the epidemiology, pathophysiology, diagnostic and therapeutic aspects of eosinophilic oesophagitis and other eosinophilic gastrointestinal diseases

BACKGROUND

Eosinophilic gastrointestinal diseases (EGIDs) are chronic, immune-mediated disorders characterised clinically by gastrointestinal symptoms and histologically by a pathologic increase in eosinophil-predominant inflammation in the gastrointestinal tract, in the absence of secondary causes of eosinophilia.

AIMS

To highlight emerging insights and research efforts into the epidemiology, pathophysiology, diagnostic and therapeutic aspects of eosinophilic oesophagitis (EoE) and non-EoE EGIDs, and discuss key remaining knowledge gaps.

METHODS

We selected and reviewed original research, retrospective studies, case series, randomised controlled trials, and meta-analyses.

RESULTS

Standardised nomenclature classifies EGIDs as EoE, eosinophilic gastritis (EoG), eosinophilic enteritis (EoN), and eosinophilic colitis (EoC). Incidence and prevalence of EoE are rising, emphasising the need to better understand how environmental risk factors and genetic features interact. Advances in understanding EoE pathophysiology have led to clinical trials of targeted therapy and the approval (in the United States) of dupilumab for EoE. Several therapies that are under investigation hope to satisfy both histologic and clinical targets. For non-EoE EGIDs, efforts are focused on better defining clinical and histopathologic disease determinants and natural history, as well as establishing new therapies.

CONCLUSIONS

Unmet needs for research are dramatically different for EoE and non-EoE EGIDs. In EoE, non-invasive diagnostic tests, clinicopathologic models that determine the risk of disease progression and therapeutic failure, and novel biologic therapies are emerging. In contrast, in non-EoE EGIDs, epidemiologic trends, diagnostic histopathologic thresholds, and natural history models are still developing for these more rare disorders.

Effect of Proton Pump Inhibitor Treatment in "PPI Non-responsive" Patients with Eosinophilic Esophagitis

BACKGROUND AND AIMS

Some eosinophilic esophagitis (EoE) patients can have a decline in eosinophil count after proton pump inhibitor (PPI) treatment without achieving histologic response, but little is known about this group. We aimed to determine the effect of PPIs on reducing esophageal eosinophilia in patients deemed non-responsive to PPI therapy.

METHODS

We analyzed prospectively collected cohort data from newly diagnosed adults with EoE who were histologic non-responders (≥15 eos/hpf) to PPI-only therapy. Symptoms, endoscopic histologic features were assessed before and after PPI. Pre- and post-PPI treatment esophageal biopsies were read by pathologists to determine peak eosinophil counts and other histologic findings.

RESULTS

Of 125 patients, peak eosinophil counts were 102.1 ± 69.8 and 102.9 ± 101.1 (p=0.93) before and after PPI treatment, respectively, but lamina propria fibrosis decreased from 97% to 41% (p<0.001). Heartburn frequency also decreased (19% to 11%; p=0.006), though endoscopic findings did not change. There were 75 patients (60%) who had some decrease in eosinophil counts, with 30 patients (24%) having ≥50% decrease in counts. When comparing the ≥50% and <50% decrease groups, differences in endoscopic features were identified, but the ≥50% group had improvement in eosinophil degranulation, microabscesses, spongiosis, and basal cell hyperplasia.

CONCLUSION

Peak eosinophil counts did not decrease overall after PPI treatment, but symptoms of heartburn improved. Approximately a quarter had ≥50% decrease in eosinophil counts, with associated decreases in other histologic findings. Further research may consider what role PPIs have in this subset of non-responders or in combination therapies.