Anti-interleukin-5 antibody treatment (mepolizumab) in active eosinophilic oesophagitis: a randomised, placebo-controlled, double-blind trial

Biologics for eosinophilic oesophagitis: a systematic review and meta-analysis

OBJECTIVE

Advancing the understanding of the pathophysiology of eosinophilic oesophagitis (EoE) and other eosinophilic gastrointestinal diseases (EGIDs) has spurred research into targeted biological therapies, while the conclusive therapeutic efficacy of biologics remains uncertain. In this review, we conducted a meta-analysis of all RCTS of biologics in the treatment of EoE to evaluate their efficacy and safety and discussed their treatment of non-EoE EGIDs.

METHODS

We searched the PubMed, EMBASE, Cochrane Library, and Web of Science databases. Double-blind randomized controlled trials comparing biologics with placebo in patients with EoE and non-EoE EGIDs were collected and further screened for inclusion and exclusion. The caliber of the included literature was evaluated using the Cochrane risk assessment tool findings. Data extraction and meta-analysis were conducted using RevMan 5.4 and Stata 17.0. Clinical response and histological remission were the major endpoints.

RESULTS

Our search retrieved 3,237 articles. There were seven trials in total, comprising 792 people with EoE. Key outcomes of this meta-analysis include the following: Anti-IL-5 biologics exhibited statistically significant benefits in histological remission (RR 2.03 [CI 1.45-2.85]; p < 0.0001) compared to the placebo, but there was no significant difference in symptom relief (RR 1.06 [CI 0.88 to 1.28]; p = 0.53); anti-IL-4/13 biologics had significant effects on histologic improvement (RR 10.48 [CI 5.54-19.82]; p < 0.00001) and symptom related score reduction (RR 1.44 [CI 1.08-1.93]; p = 0.01), with a better outcome for endoscopic remission than with placebo (SMD-1.06 [CI-1.26-0.86], p < 0.00001); no statistically significant differences in adverse effects were observed between the intervention and control groups.

CONCLUSIONS

Our findings suggest that the biologics currently being investigated are considered safe and effective treatments for EoE, while their efficiency varies. However, the discussion of biologics in non-pharyngitis EGID is hampered by a lack of research, necessitating more research in high-quality trials.

Histological Outcomes of Pharmacological Interventions in Eosinophilic Esophagitis for Adults and Children: A Network Meta-analysis of Randomized Controlled Trials

INTRODUCTION

Multiple pharmacological interventions have been studied for managing eosinophilic esophagitis (EoE). We performed a comprehensive systematic review and network meta-analysis of all available randomized controlled trials (RCT) to assess the efficacy and safety of these interventions in EoE in adults and children.

METHODS

We performed a comprehensive review of Embase, PubMed, MEDLINE OVID, Cochrane CENTRAL, and Web of Science through May 10, 2023. We performed frequentist approach network meta-analysis using random effects model. We calculated the odds ratio (OR) with 95% CI for dichotomous outcomes.

RESULTS

Our search yielded 25 RCTs with 25 discrete interventions and 2067 patients. Compared with placebo, the following interventions improved histology (using study definitions) in decreasing order on ranking: orodispersible budesonide (ODB) low dose, ODB high dose, oral viscous budesonide (OVB) high dose, fluticasone tablet 1.5 mg twice daily, fluticasone 3 mg twice daily, esomeprazole, dupilumab every 2 weeks, dupilumab weekly, OVB medium dose, fluticasone 3 mg daily, cendakimab 180 mg, prednisone, swallowed fluticasone, fluticasone tablet 1.5 mg daily, OVB low dose, reslizumab 3 mg/kg, reslizumab 1 mg/kg, and reslizumab 2 mg/kg.

CONCLUSIONS

Network meta-analysis demonstrates histological efficacy of multiple medications for EoE. Because of the heterogeneity and large effect size, we recommend more trials comparing pharmacotherapeutic interventions with each other and placebo. An important limitation of this study is absence of clinical efficacy data due to insufficient data. Other limitations include heterogeneity of operator, population, and outcome analysis.

New Therapeutic Challenges in Pediatric Gastroenterology: A Narrative Review

Pediatric gastroenterology is entering a pivotal phase marked by significant challenges and emerging opportunities in treating conditions like celiac disease (CeD), eosinophilic esophagitis (EoE), inflammatory bowel disease (IBD), and autoimmune hepatitis (AIH) pose significant clinical hurdles, but new therapeutic avenues are emerging. Advances in precision medicine, particularly proteomics, are reshaping care by tailoring treatments to individual patient characteristics. For CeD, therapies like gluten-degrading enzymes (latiglutenase, Kuma030) and zonulin inhibitors (larazotide acetate) show promise, though clinical outcomes are inconsistent. Immunotherapy and microbiota modulation, including probiotics and fecal microbiota transplantation (FMT), are also under exploration, with potential benefits in symptom management. Transglutaminase 2 inhibitors like ZED-1227 could help prevent gluten-induced damage. Monoclonal antibodies targeting immune pathways, such as AMG 714 and larazotide acetate, require further validation in pediatric populations. In EoE, biologics like dupilumab, cendakimab, dectrekumab (IL-13 inhibitors), and mepolizumab, reslizumab, and benralizumab (IL-5/IL-5R inhibitors) show varying efficacy, while thymic stromal lymphopoietin (TSLP) inhibitors like tezepelumab are also being investigated. These therapies require more pediatric-specific research to optimize their use. For IBD, biologics like vedolizumab, ustekinumab, and risankizumab, as well as small molecules like tofacitinib, etrasimod, and upadacitinib, are emerging treatments. New medications for individuals with refractory or steroid-dependent AIH have been explored. Personalized therapy, integrating precision medicine, therapeutic drug monitoring, and lifestyle changes, is increasingly guiding pediatric IBD management. This narrative review explores recent breakthroughs in treating CeD, EoE, IBD, and AIH, with a focus on pediatric studies when available, and discusses the growing role of proteomics in advancing personalized gastroenterological care.

CSF1-dependent macrophage support matrisome and epithelial stress-induced keratin remodeling in Eosinophilic esophagitis

Atopic diseases such as Eosinophilic Esophagitis (EoE) often progress into fibrosis (FS-EoE), compromising organ function with limited targeted treatment options. Mechanistic understanding of FS-EoE progression is confounded by the lack of preclinical models and the heavy focus of research on eosinophils themselves. We found that macrophage accumulation precedes esophageal fibrosis in FS-EoE patients. We developed a FS-EoE model via chronic administration of oxazalone allergen, in a transgenic mouse over-expressing esophageal epithelial hIL-5 (L2-IL5OXA). These mice display striking histopathologic features congruent with that found in FS-EoE patients. Unbiased proteomic analysis, using a unique extracellular-matrix (ECM) focused technique, identified an inflammation-reactive provisional basal lamina membrane signature and this was validated in two independent EoE patient RNA-sequencing/proteomic cohorts, supporting model significance. A wound healing signature was also observed involving hemostasis-associated molecules previously unnoted in EoE. We further identified the ECM glycoprotein, Tenascin-C (TNC), and the stress-responsive keratin-16 (KRT16) as IL-4 and IL-13 responsive mediators, acting as biomarkers of FS-EoE. To mechanistically address how the immune infiltrate shapes FS-EoE progression, we phenotyped the major immune cell subsets that coalesce with fibrosis in both the L2-IL5OXA mice and in FS-EoE patients. We found that macrophage are required for matrisome and cytoskeletal remodeling. Importantly, we show that macrophage accumulation precedes esophageal fibrosis and provide a novel therapeutic target in FS-EoE as their depletion with anti-CSF1 attenuated reactive matrisome and cytoskeletal changes. Thus, macrophage-based treatments and the exploration of TNC and KRT16 as biomarkers may provide novel therapeutic options for patients with fibrostenosis.

Effect of mepolizumab in airway remodeling in patients with late-onset severe asthma with an eosinophilic phenotype

BACKGROUND

Clinical trials and real-world experience have provided evidence for the clinical benefits of mepolizumab, an anti-IL-5 biologic, in severe asthma. However, limited data exist regarding the impact of mepolizumab on airway remodeling.

OBJECTIVE

We sought to investigate the effect of mepolizumab on airway structural remodeling in patients treated for severe asthma in routine clinical care.

METHODS

The MESILICO (Efficacy of Mepolizumab in patients with latE-onset Severe eosInophiLic asthma and fIxed obstruCtiOn) study is a multicenter study involving 8 pulmonology departments in Greece. This study focused on patients who initiated mepolizumab for severe asthma with an eosinophilic phenotype and had late-onset disease with obstructive patterns (impaired reversibility). Forty-seven patients were recruited, of whom 41 were enrolled in the bronchoscopy substudy. The findings were related to clinical outcome.

RESULTS

After 12 months, mepolizumab treatment was associated with significant improvements in lung function and Asthma Control Test score, along with a significant decrease in severe exacerbation events (P < .001). Thirty-four of the 41 participants (83%) had paired biopsies for comparative analysis. There was a significant reduction from baseline in sub-basement membrane thickness, airway smooth muscle area, airway smooth muscle layer thickness, extent of epithelial damage, and number of tissue eosinophils (all P < .001). The extent of reduction in airway smooth muscle layer thickness positively correlated with the submucosal eosinophil reduction (r = 0.599; P < .001).

CONCLUSIONS

This study identified that 12 months of mepolizumab treatment in patients with late-onset severe asthma, who are also characterized by eosinophilic and impaired reversibility phenotypes, not only leads to clinical improvement but also reduces indices of airway tissue remodeling suggestive of a disease-modifying effect.

Meta-Analysis: Evaluating Placebo Rates Across Outcomes in Eosinophilic Oesophagitis Randomised Controlled Trials

BACKGROUND

High placebo responses have limited drug development in eosinophilic oesophagitis. The optimal configuration of trial outcomes is uncertain.

AIMS

To inform more efficient future trial designs, to characterise clinical, endoscopic and histologic placebo responses in eosinophilic oesophagitis randomised controlled trials (RCTs).

METHODS

We updated a Cochrane systematic review and meta-analysis, searching multiple databases to January 1, 2024, to identify placebo-controlled RCTs evaluating medical therapies for patients with eosinophilic oesophagitis. The primary outcome was the pooled proportion of study-defined clinical, endoscopic and histologic responders and remitters randomised to placebo, using an intention-to-treat approach and random-effects model. Sources of heterogeneity were explored using meta-regression.

RESULTS

We included 25 RCTs. The pooled proportion of clinical response was 41.0% [95% CI: 29.7%-52.8%] with substantial heterogeneity (I2 = 74.9%). On meta-regression, older age and a higher probability of being randomised to placebo reduced the likelihood of clinical response to placebo. The pooled proportion of histologic remission defined as a peak eosinophil count [PEC] ≤ 6 eosinophils per high power field [HPF] or ≤ 1 eosinophil/HPF was 4.3% [95% CI: 2.6%-6.2%] (I2 = 23.6%) and 1.3% [95% CI: 0.5%-2.5%] (I2 = 0%), respectively. The standardised mean difference in the Eosinophilic Oesophagitis Endoscopic Reference Score to placebo was -0.25 [95% CI: -0.41, -0.10].

CONCLUSIONS

Over 40% of patients in eosinophilic oesophagitis trials respond clinically to placebo, and this is associated with trial design factors such as randomisation ratio and trial population. Objective endoscopic and histologic measures are associated with very low placebo responses.

Eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is an atopic condition of the esophagus that has become increasingly recognized. Diagnosis of the disorder is dependent on the patient's clinical manifestations and must be confirmed by histologic findings on esophageal mucosal biopsies. The epidemiology, pathophysiology, diagnosis, treatment, and prognosis of EoE are discussed in this review.

Successful novel use of dupilumab for gastrointestinal involvement of idiopathic hypereosinophilic syndrome: case report and review of the literature

Hypereosinophilic syndrome (HES) is characterized by blood and tissue hypereosinophilia leading to organ damage. Gastrointestinal involvement is the third most common manifestation. We present a patient with idiopathic HES with secondary eosinophilic esophagitis (EoE), gastritis, and enteritis, corticosteroids-dependent, azathioprine- and mepolizumab-refractory. The patient achieved clinical and histopathologic remission following dupilumab treatment. A 28 year-old female presented with chronic episodic nausea and emesis since childhood and initial diagnosis of primary eosinophilic gastrointestinal disease (EGID), improved with corticosteroids, refractory to azathioprine. She was found to have peripheral eosinophilia and multifactorial anemia, with iron, B12, and folate deficiencies. Esophageal, gastric, duodenal, and terminal ileum biopsies showed significant eosinophilic infiltrate. Bone marrow biopsy at age 31 confirmed HES diagnosis. By age 32, she became total parental nutrition (TPN)-dependent. She failed trials of benralizumab and mepolizumab [anti-interleukin (IL)-5 inhibitors], and cromolyn (mast-cell stabilizer). After developing new esophageal stricture, we initiated dupilumab (IL-4/13 inhibitor), recently FDA-approved for EoE. After 9 weeks, esophageal stricture, gut tissue eosinophilia, and prior intestinal ulcerations resolved. She ceased TPN and is tolerating a non-restricted diet, with complete symptom resolution. Our patient's complete remission with dupilumab shows promise for broadening its use in treating GI involvement in HES, along with primary EGIDs.

Off-Label Use of Monoclonal Antibodies for Eosinophilic Esophagitis in Humans: A Scoping Review

Background: Eosinophilic esophagitis (EoE) is a rare, chronic immune-mediated disorder with limited treatment options. Despite the U.S. Food and Drug Administration (FDA) approval of dupilumab for EoE, other monoclonal antibodies remain unapproved and are used off-label with limited evidence on their efficacy and safety. This systematic review rigorously and comprehensively evaluates the evidence for monoclonal antibody therapies used off-label to treat EoE. Methods: We conducted a systematic review across PubMed, EMBASE, Cochrane Central, and ClinicalTrials.gov, assessing the efficacy and safety of off-label monoclonal antibodies in EoE through clinical outcomes and the FDA Adverse Event Reporting System (FAERS) data. Results: Among ten monoclonal antibodies reviewed, mepolizumab that targets IL-5 showed the most promise with a moderate recommendation based on Level 2 evidence. Others like omalizumab (anti-IgE), dectrekumab (anti-IL-13), and reslizumab (anti-IL-5) showed limited utility. Safety evaluations via the FAERS database revealed significant adverse drug reactions, including serious events like asthmatic crises, pneumonia, and adrenal insufficiency for mepolizumab and reslizumab, as well as chronic obstructive pulmonary disease and gastroenteritis for omalizumab. Dectrekumab's safety profile remains unclear due to a lack of data. Conclusions: While mepolizumab demonstrates potential as an off-label treatment, none of the antibodies reviewed have FDA approval for EoE. Clinicians should consider the balance between local and systemic effects and exercise caution, closely monitoring for adverse effects, particularly in patients with respiratory comorbidities. Continued research is crucial to establish a more robust evidence base for these therapies.

Advancements in Biologic Therapies for Eosinophilic Gastrointestinal Diseases: A Comprehensive Review

Eosinophilic gastrointestinal diseases (EGIDs) encompass a group of disorders characterized by an abnormal accumulation of eosinophils in various parts of the gastrointestinal tract. EGIDs present with a wide range of symptoms such as abdominal pain, vomiting, diarrhea, difficulty swallowing, and food impaction. Monoclonal antibodies, targeting inflammatory cytokines or eosinophils, are the next emerging therapy for EGIDs. The only Food and Drug Administration-approved monoclonal antibody is dupilumab, and it has been approved for the treatment of eosinophilic esophagitis (EoE). In this article, the authors will discuss biologics that have been used in the treatment of eosinophilic gastrointestinal diseases.

Odynophagia and Retrosternal Pain Are Common in Eosinophilic Esophagitis and Associated with an Increased Overall Symptom Severity

BACKGROUND AND AIMS

Dysphagia is the hallmark symptom in eosinophilic esophagitis (EoE). However, data are limited regarding the overall prevalence and potential implications of atypical symptoms like odynophagia and retrosternal pain.

METHODS

Patients enrolled into the Swiss EoE cohort study (SEECS) were analyzed regarding the presence of odynophagia and retrosternal pain. Demographics, other EoE-related symptoms, histologic and endoscopic activity were compared between EoE-patients with vs. without odynophagia and/or retrosternal pain.

RESULTS

474 patients (75.2% male) were analyzed. In their individual course of disease 110 (23.2%) patients stated to have ever experienced odynophagia and 64 (13.5%) retrosternal pain independent of food intake, 24 (5%) patients complained about both symptoms. Patients with odynophagia consistently scored higher in symptom severity (p < 0.001), EREFS score (median 3.0 vs. 2.0, p = 0.006), histologic activity and a lower quality of life (p = 0.001) compared to patients without odynophagia. Sex, age at diagnosis, EoE-specific treatment, complications such as candida or viral esophagitis and disease duration were similar in patients with vs. without odynophagia. Also patients with retrosternal pain scored higher in symptom severity (2.0 vs. 1.0, p = 0.001 and 2.0 vs. 1.0, p < 0.001 in physician and patient questionnaire assessment, respectively). However, there was neither a difference in endoscopic/histologic disease activity nor in quality of life according to presence or absence of retrosternal pain. Due to logistic reasons, a stratification regarding the presence of concomitant dysphagia was not possible.

CONCLUSION

Odynophagia and swallowing-independent retrosternal pain are common symptoms in patients with EoE, associate with an overall higher EoE-related symptom severity and for the case of odynophagia lower quality of life. However, the influence of concomitant dysphagia and its severity remains unclear and needs to be included in future analyses.

Eosinophilic esophagitis and inhalant antigens: Pointing out the roles of allergic rhinitis, immunotherapy and biologic treatment

Eosinophilic esophagitis (EoE) and allergic rhinitis (AR) usually represent the latest manifestations of the atopic march, sharing a common type 2 inflammation response. A relevant prevalence of AR in EoE cohorts has been widely confirmed. An increasing literature assessed the involvement of aeroantigens in EoE pathogenesis, focusing foremost on the seasonality of new diagnoses, symptoms, and response to therapy. Unfortunately, no diriment direction has been achieved, probably due to the retrospective design of the studies so far available, which chose surrogate markers of EoE activity (mostly the date of new diagnosis) which may be affected by geographical, logistic and personal factors, probably not dependent by the disease itself. EoE exacerbations reported in the context of the pollen levels (preferably pollen counts) may represent a more reliable marker. AR might promote the onset and the re-exacerbation of EoE through mechanisms that are both local (ie, massive exposure to airborne antigens mediated by post-nasal drip) and systemic (type 2 inflammation). Furthermore, AR may facilitate EoE onset by predisposing to pollen food allergic syndrome (PFAS), and EoE patients with PFAS reported higher rate of AR, thus suggesting a bond among these 3 conditions whose causative relationship have still to be ascertained. In addition, because of its shifting activity from Th2 to Th1 inflammation, several case reports focused on the effect of allergen immunotherapy (AIT) employed to treat AR in EoE patients. Also in this instance, no certainties could be guaranteed, although sublingual immunotherapy (SLIT) is more frequently reported to exacerbate EoE, while SCIT is mostly described as a remission adjuvant. The real life experience reported from our allergy service appears to confirm such hypothesis. Finally, a watchful eye should be reserved to monoclonal antibodies as a potential future option for concomitant EoE and AR. In light of all this, an attentive evaluation of allergic history of EoE patients should be relevant. Future perspectives should be addressed on prospective studies targeted to shed light on causative relations among airborne antigens, AR and EoE, and to viable comprehensive treatments.

Interleukin-5 as a pleiotropic cytokine orchestrating airway type 2 inflammation: Effects on and beyond eosinophils

Interleukin (IL)-5 is the key cytokine in the maturation, activation, proliferation, migration and survival of eosinophils, which are key effector cells in many upper and lower airway diseases. Through its effects on eosinophils, IL-5 indirectly contributes to various pathophysiological processes including tissue damage, repair and remodelling. Understanding the importance of IL-5 in eosinophil-associated diseases led to the development of anti-IL-5 therapies, which provide clinical benefits across a range of conditions. However, recent evidence suggests that eosinophil-depletion alone may not account for all of the therapeutic effects of anti-IL-5 therapy and that IL-5 may also contribute to disease independently of its effects on eosinophils. Indeed, evidence from ex vivo studies and targeted therapy in vivo demonstrates that IL-5 and its inhibition affects a much broader range of cells beyond eosinophils, including epithelial cells, plasma cells, mast cells, basophils, neutrophils, type 2 innate lymphoid cells, T regulatory cells and fibroblasts. This review will provide an update on the evidence supporting the breadth of IL-5 biology relevant to disease pathogenesis beyond eosinophil-associated inflammation, where there is a need for additional insight, and the clinical implications of a more central role of IL-5 in type 2 inflammation.

Losartan Treatment Reduces Esophageal Eosinophilic Inflammation in a Subset of Eosinophilic Esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic, food antigen-driven esophageal disorder. Connective tissue disorders (CTDs) and esophageal connective tissue alterations are associated with EoE. Therefore, angiotensin II type 1 receptor blockade with losartan, an accepted CTD treatment, is a potential EoE treatment.

OBJECTIVE

We evaluated losartan's effects on esophageal pathology, symptoms, and safety in patients with EoE with and without a CTD in an open-label, non-placebo controlled multisite study.

METHODS

Fifteen participants with EoE, aged 5 to 23 years, underwent treatment with per-protocol titrated doses of losartan in an open-label, 16-week pilot trial. Losartan was added to standard of care therapy and 14 patients completed the study. Eosinophil counts served as the primary end point, whereas we also assessed the EoE Histology Scoring System, Endoscopic Reference Scores, EoE Diagnostic Panel, and patient-reported outcomes.

RESULTS

Esophageal eosinophilia was not reduced after losartan. The peak eosinophil count was not reduced for the proximal (median [interquartile range]: -3 [-22 to 3]; P = .49) and distal esophagus (median [interquartile range]: -18 [-39 to -1]; P = .23). There were no differences in losartan response in EoE with or without CTD (n = 7 and 8, respectively). Regardless, in a small subset of four participants esophageal eosinophilia was resolved with a concomitant reduction in EoE Histology Scoring System score and Endoscopic Reference Score. Across all subjects, the Pediatric EoE Symptom Score, Pediatric Quality of Life Inventory EoE Module, and EoE Diagnostic Panel improved after losartan (P < .05).

CONCLUSIONS

Losartan treatment was associated with improved patient-reported outcome scores and EoE Diagnostic Panel biomarkers although without a reduction in esophageal eosinophilia overall. A subset of patients demonstrated improved histopathologic and endoscopic features that could not be tied to a specific feature predicting response to treatment.

From Pathogenesis to Treatment: Targeting Type-2 Inflammation in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic inflammatory disorder of the esophagus. EoE shares a common pathogenetic mechanism with other chronic disorders pertaining to the type 2 inflammatory spectrum, such as atopic dermatitis (AD), allergic rhinitis (AR), asthma, and chronic rhinosinusitis with nasal polyps (CRSwNP). The recent advancements in EoE pathogenesis understanding have unveiled new molecular targets implied within the "atopic march" picture as well as specific to EoE. These discoveries have led to the clinical evaluation of several novel drugs (monoclonal antibodies and immune modulators), specifically aimed at the modulation of Th2 inflammation. In this comprehensive review, we have focused on the subtle mechanisms of type 2 inflammatory disorders, highlighting the similarities and differences with EoE, taking a deeper look into the evolving field of biologic therapies, already approved or under current investigation.

Eosinophilic Esophagitis and Inflammatory Bowel Disease: What Are the Differences?

Eosinophilic esophagitis (EoE) and inflammatory bowel disease (IBD) are chronic inflammatory disorders of the gastrointestinal tract, with EoE predominantly provoked by food and aeroallergens, whereas IBD is driven by a broader spectrum of immunopathological and environmental triggers. This review presents a comprehensive comparison of the pathophysiological and therapeutic strategies for EoE and IBD. We examine the current understanding of their underlying mechanisms, particularly the interplay between environmental factors and genetic susceptibility. A crucial element in both diseases is the integrity of the epithelial barrier, whose disruption plays a central role in their pathogenesis. The involvement of eosinophils, mast cells, B cells, T cells, dendritic cells, macrophages, and their associated cytokines is examined, highlighting the importance of targeting cytokine signaling pathways to modulate immune-epithelial interactions. We propose that advances in computation tools will uncover the significance of G-protein coupled receptors (GPCRs) in connecting immune and epithelial cells, leading to novel therapies for EoE and IBD.

Diagnosis and management of eosinophilic esophagitis in children: An update from the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN)

INTRODUCTION

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the esophagus characterized by symptoms of esophageal dysfunction and histologically by predominantly eosinophilic infiltration of the squamous epithelium. European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) published a guideline in 2014; however, the rapid evolution of knowledge about pathophysiology, diagnostic criteria, and therapeutic options have made an update necessary.

METHODS

A consensus group of pediatric gastroenterologists from the ESPGHAN Working Group on Eosinophilic Gastrointestinal Diseases (ESPGHAN EGID WG) reviewed the recent literature and proposed statements and recommendations on 28 relevant questions about EoE. A comprehensive electronic literature search was performed in MEDLINE, EMBASE, and Cochrane databases from 2014 to 2022. The Grading of Recommendations Assessment, Development and Evaluation system was used to assess the quality of evidence and formulate recommendations.

RESULTS

A total of 52 statements based on the available evidence and 44 consensus-based recommendations are available. A revision of the diagnostic protocol, options for initial drug treatment, and the new concept of simplified empiric elimination diets are now available. Biologics are becoming a part of the potential armamentarium for refractory EoE, and systemic steroids may be considered as the initial treatment for esophageal strictures before esophageal dilation. The importance and assessment of quality of life and a planned transition to adult medical care are new areas addressed in this guideline.

CONCLUSION

Research in recent years has led to a better understanding of childhood EoE. This guideline incorporates the new findings and provides a practical guide for clinicians treating children diagnosed with EoE.

Biologic therapy in rare eosinophil-associated disorders: remaining questions and translational research opportunities

Rare eosinophil-associated disorders (EADs), including hypereosinophilic syndrome, eosinophilic granulomatosis with polyangiitis, and eosinophilic gastrointestinal disorders, are a heterogeneous group of conditions characterized by blood and/or tissue hypereosinophilia and eosinophil-related clinical manifestations. Although the recent availability of biologic therapies that directly and indirectly target eosinophils has the potential to dramatically improve treatment options for all EADs, clinical trials addressing their safety and efficacy in rare EADs have been relatively few. Consequently, patient access to therapy is limited for many biologics, and the establishment of evidence-based treatment guidelines has been extremely difficult. In this regard, multicenter retrospective collaborative studies focusing on disease manifestations and treatment responses in rare EADs have provided invaluable data for physicians managing patients with these conditions and helped identify important questions for future translational research. During the Clinical Pre-Meeting Workshop held in association with the July 2023 biennial meeting of the International Eosinophil Society in Hamilton, Ontario, Canada, the successes and limitations of pivotal multicenter retrospective studies in EADs were summarized and unmet needs regarding the establishment of guidelines for use of biologics in rare EADs were discussed. Key topics of interest included (1) clinical outcome measures, (2) minimally invasive biomarkers of disease activity, (3) predictors of response to biologic agents, and (4) long-term safety of eosinophil depletion. Herein, we report a summary of these discussions, presenting a state-of-the-art overview of data currently available for each of these topics, the limitations of the data, and avenues for future data generation through implementation of multidisciplinary and multicenter studies.

The 1st EoETALY Consensus on the Diagnosis and Management of Eosinophilic Esophagitis-Current Treatment and Monitoring

The present document constitutes Part 2 of the EoETALY Consensus Statements guideline on the diagnosis and management of eosinophilic esophagitis (EoE) developed by experts in the field of EoE across Italy (i.e., EoETALY Consensus Group). Part 1 was published as a different document, and included three chapters discussing 1) definition, epidemiology, and pathogenesis; 2) clinical presentation and natural history and 3) diagnosis of EoE. The present work provides guidelines on the management of EoE in two final chapters: 4) treatment and 5) monitoring and follow-up, and also includes considerations on knowledge gaps and a proposed research agenda for the coming years. The guideline was developed through a Delphi process, with grading of the strength and quality of the evidence of the recommendations performed according to accepted GRADE criteria.This document has received the endorsement of three Italian national societies including the Italian Society of Gastroenterology (SIGE), the Italian Society of Neurogastroenterology and Motility (SINGEM), and the Italian Society of Allergology, Asthma, and Clinical Immunology (SIAAIC). The guidelines also involved the contribution of members of ESEO Italia, the Italian Association of Families Against EoE.

Efficacy and Safety of Monoclonal Antibodies for the Treatment of Eosinophilic Esophagitis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND AIMS

Monoclonal antibodies (MAbs) have clinical benefits for treating several atopic diseases. However, consensus on its use for eosinophilic esophagitis (EoE) is lacking. The present meta-analysis aimed to compare the efficacy and safety of MAbs versus placebo for treating EoE.

METHODS

We searched PubMed, Embase, and Cochrane Library for randomized controlled trials (RCTs). The primary outcomes were changes in peak esophageal eosinophils count/high power field (HPF) and mean esophageal eosinophils count/HPF. The secondary outcomes were changes in the EoE-Histology Scoring System (EoE-HSS), Endoscopic Reference Score (EREFS), dysphagia score, and adverse events (AEs). We compared binary outcomes using risk ratio (RR) and continuous outcomes using mean difference (MD) or standardized mean difference (SMD), with 95% confidence interval (CI). Considering the diversity of mechanistic properties of MAbs, a pre-specified subgroup analysis by MAb mechanism of action was performed for all outcomes, provided that at least two studies were in each subgroup. Heterogeneity was assessed using Cochran's Q test and I2 statistics.

RESULTS

6 RCTs were included (533 patients). Compared to placebo, MAbs led to a significant reduction in peak esophageal eosinophils count/HPF (MD -0.78; CI 95% -0.87, -0.6801) and mean esophageal eosinophils count/HPF (SMD -0.79; CI 95% -1.5, -0.08). Moreover, MAbs significantly reduced EoE-HSS scores (grade score: SMD -9.31; 95% CI -13.95, -4.6701; stage score: SMD -10.18; 95% CI -15.06, -5.31), EREFS (SMD -5.95; CI 95% -9.19, -2.71) and dysphagia score (SMD -1.79; CI 95% -3.36, -0.23) without increasing AEs compared to placebo. Among those MAbs whose mechanism of action includes the blockage of the receptor for IL-13 (Dupilumab, QAX576, and RPC4046), the scores of EoE-HSS grade, EoE-HSS stage, EREFS, and dysphagia were significantly reduced, and they presented a similar risk of overall and serious AEs compared to placebo.

CONCLUSION

MAbs seem effective and safe in reducing esophageal eosinophil infiltrate, EoE-HSS score, EREFS score, and dysphagia symptoms in patients with EoE. However, further evidence is needed to establish its place in EoE management.

Expression of CD25, mast cell markers and T-cell markers in eosinophilic esophagitis

While eosinophilic esophagitis (EOE) is defined by histologic presence of eosinophils, a few studies have established the presence of mast cells in EOE and even shown their correlation with symptom persistence despite resolution of eosinophils. Expression of aberrant mast cell markers CD25 and CD2 have not been studied in EOE. This study quantifies the number of hotspot cells per high power field expressing CKIT/CD117, tryptase, CD25, CD2 and CD3 by immunohistochemical stains in endoscopic esophageal biopsies of the following three cohorts: (1) established and histologically confirmed EOE, (2) suspected EOE with biopsies negative for eosinophils, and (3) no history of or suspicion for EOE with histologically unremarkable biopsies. In this study, mast cells were highlighted by CKIT and tryptase in EOE, and not seen in other clinically mimicking cases. There were also significantly higher densities of CD25 and pan-T-cell marker staining in EOE cases. These findings suggest an inflammatory cellular milieu in EOE, beyond just eosinophils, that can be demonstrated by immunohistochemistry, and that invite further study into the role that these cells may play in EOE.

Eosinophilic esophagitis in the era of biologics

INTRODUCTION

Eosinophilic esophagitis (EoE) is a chronic inflammatory, disabling disorder characterized by prominent eosinophilic inflammation of the esophagus, leading to troublesome symptoms including dysphagia and food impaction. The natural history of EoE is poorly known, but it may lead to esophageal strictures. The therapeutic armamentarium is expected to grow in the near future, especially due to the availability of novel biological therapies targeting crucial inflammatory pathways of EoE.

AREAS COVERED

In this review, we discuss the main clinical features and natural history of EoE, focusing on the current therapeutic strategies, as well as past and current trials investigating biologics for its treatment.

EXPERT OPINION

Dupilumab has been the first approved biologic drug for the treatment of EoE; long-term studies assessing how it could change the natural history of EoE are awaited. Novel biological drugs or other molecules are currently under study and could change the current treatment algorithms in the near future. Proper drug positioning and long term 'exit strategies' are yet to be defined.

Anti-IL-5 Pathway Agents in Eosinophilic-Associated Disorders Across the Lifespan

Monoclonal antibodies targeting interleukin (IL)-5 pathways have revolutionized the treatment expectations for eosinophilic-associated conditions, particularly in patients with respiratory involvement. Mepolizumab (IL-5 antagonist monoclonal antibody), benralizumab (IL-5 receptor blocker monoclonal antibody), and reslizumab (IL-5 antagonist monoclonal antibody) have collectively contributed to the overall improvement of the disease burden in various conditions. Eosinophilic asthma currently boasts the most robust evidence across all age groups: all three biologics are approved for adults (aged ≥18 years); mepolizumab is approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) also in children (aged ≥ 6 years), while bernalizumab was recently approved by the FDA for patients aged ≥6 years in the USA. In chronic rhinosinusitis with nasal polyps, subcutaneous mepolizumab is the only anti-IL-5 therapy approved so far and can be used in adult patients (aged ≥18 years). For eosinophilic esophagitis, conflicting evidence surrounds both mepolizumab, reslizumab, and benralizumab, leading to non-approval of these agents by the FDA/EMA. Recently, mepolizumab was approved for eosinophilic granulomatosis with polyangiitis patients aged ≥6 years or older and for hypereosinophilic syndrome adult patients. A phase III trial proving noninferiority of benralizumab versus mepolizumab in eosinophilic granulomatosis with polyangiitis has been recently published, while evidence on reslizumab is scant. Overall, current evidence on anti-IL-5 biologics for eosinophilic-associated disorders is mostly focused on adults, whereas data for individuals aged under 18 years and over 65 years are scarce, resulting in a lack of evidence, particularly regarding efficacy, for the use of anti-IL-5 agents in these specific patient populations. This review addresses high-quality evidence from randomized controlled trials and real-world post-marketing studies regarding the use of anti-IL-5 therapies for eosinophilic-associated disorders across all age groups, spanning childhood, adulthood, and older age.

Pharmacologic Management of Non-Eosinophilic Esophagitis Eosinophilic Gastrointestinal Diseases

Data for pharmacologic treatments for non-eosinophilic esophagitis (EoE) eosinophilic gastrointestinal diseases (EGIDs) are limited. Nevertheless, because of the increasing understanding of EGID pathogenesis, a number of medications are used to treat EGIDs, though all are currently off-label. Initial therapy generally starts with corticosteroids, and "topical" delivery is preferred over systemic due to long-term side effects. A number of other small molecules could potentially be used, ranging from allergy medications to immunosuppressants. Biologics are also being used and investigated for EGIDs and represent promising targeted therapies. Multiple therapeutic targets have also been identified, many of which overlap with EoE targets.

Pathophysiology and Clinical Impact of Esophageal Remodeling and Fibrosis in Eosinophilic Esophagitis

Most of the major clinical signs and consequences of eosinophilic esophagitis seem to be related to tissue remodeling. Important data on remodeling activity in patients with eosinophilic esophagitis are provided by a range of current and new biologic markers and diagnostics. To completely clarify the possible advantages and restrictions of therapeutic approaches, clinical studies should take into consideration the existence and reversibility of esophageal remodeling. The degree of mucosal or submucosal disease activity may not be reflected by epithelial eosinophilic inflammation, which is used to define one criterion of disease activity".

Pharmacologic Management of Eosinophilic Esophagitis

Proton pump inhibitors (PPIs), swallowed topical corticosteroids (STSs), and dupilumab are highly effective therapies for the treatment of eosinophilic esophagitis. Shared decision-making informs the choice of therapy and factors such as ease of use, safety, cost, and efficacy should be addressed. PPIs are the most common medication utilized early in the disease course; however, for nonresponders, STSs are an excellent alternative. Dupilumab is unlikely to replace PPIs or STSs as first-line therapy, except in highly specific circumstances. Identification of novel biologic pathways and the development of small molecules may lead to a wider range of treatment options in the future.

Endoscopic Features of Eosinophilic Gastrointestinal Diseases

Endoscopic evaluation with biopsies is a mainstay of the diagnosis of eosinophilic esophagitis (EoE) and non-EoE eosinophilic gastrointestinal diseases (EGIDs). Increasing knowledge has resulted in the development of 2 standardized scoring systems: the Endoscopic REFerence Score (EREFS) for EoE and the EG-REFS for eosinophilic gastritis, although the latter has not been validated. In EGIDs, diagnosis and follow-up focus on eosinophil infiltration in biopsies. In this article, we will discuss the most commonly used endoscopic scores in EoE and non-EoE EGIDs, their validity for the diagnosis and follow-up of disease activity, as well as endoscopic interventions and areas of uncertainty.

World Health Organization and International Consensus Classification of eosinophilic disorders: 2024 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

The eosinophilias encompass a broad range of non-hematologic (secondary or reactive) and hematologic (primary or clonal) disorders with the potential for end-organ damage.

DIAGNOSIS

Hypereosinophilia (HE) has generally been defined as a peripheral blood eosinophil count greater than 1.5 × 109/L, and may be associated with tissue damage. After the exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of various tests. They include morphologic review of the blood and marrow, standard cytogenetics, fluorescence in situ hybridization, molecular testing and flow immunophenotyping to detect histopathologic or clonal evidence for an acute or chronic hematolymphoid neoplasm.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2022 World Health Organization and International Consensus Classification endorse a semi-molecular classification scheme of disease subtypes. This includes the major category "myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions" (MLN-eo-TK), and the MPN subtype, "chronic eosinophilic leukemia" (CEL). Lymphocyte-variant HE is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) is a diagnosis of exclusion.

RISK-ADAPTED THERAPY

The goal of therapy is to mitigate eosinophil-mediated organ damage. For patients with milder forms of eosinophilia (e.g., <1.5 × 109/L) without symptoms or signs of organ involvement, a watch and wait approach with close follow-up may be undertaken. Identification of rearranged PDGFRA or PDGFRB is critical because of the exquisite responsiveness of these diseases to imatinib. Pemigatinib was recently approved for patients with relapsed or refractory FGFR1-rearranged neoplasms. Corticosteroids are first-line therapy for patients with lymphocyte-variant HE and HES. Hydroxyurea and interferon-α have demonstrated efficacy as initial treatment and in steroid-refractory cases of HES. Mepolizumab, an interleukin-5 (IL-5) antagonist monoclonal antibody, is approved by the U.S Food and Drug Administration for patients with idiopathic HES. Cytotoxic chemotherapy agents, and hematopoietic stem cell transplantation have been used for aggressive forms of HES and CEL, with outcomes reported for limited numbers of patients. Targeted therapies such as the IL-5 receptor antibody benralizumab, IL-5 monoclonal antibody depemokimab, and various tyrosine kinase inhibitors for MLN-eo-TK, are under active investigation.

Neuroimmune interplay during type 2 inflammation: Symptoms, mechanisms, and therapeutic targets in atopic diseases

Type 2 inflammation is characterized by overexpression and heightened activity of type 2 cytokines, mediators, and cells that drive neuroimmune activation and sensitization to previously subthreshold stimuli. The consequences of altered neuroimmune activity differ by tissue type and disease; they include skin inflammation, sensitization to pruritogens, and itch amplification in atopic dermatitis and prurigo nodularis; airway inflammation and/or hyperresponsiveness, loss of expiratory volume, airflow obstruction and increased mucus production in asthma; loss of sense of smell in chronic rhinosinusitis with nasal polyps; and dysphagia in eosinophilic esophagitis. We describe the neuroimmune interactions that underlie the various sensory and autonomic pathologies in type 2 inflammatory diseases and present recent advances in targeted treatment approaches to reduce type 2 inflammation and its associated symptoms in these diseases. Further research is needed to better understand the neuroimmune mechanisms that underlie chronic, sustained inflammation and its related sensory pathologies in diseases associated with type 2 inflammation.

Eosinophilic Esophagitis: What the Otolaryngologist Needs to Know

Eosinophilic esophagitis is a male-predominant disease with presentations ranging from nonspecific feeding issues to dysphagia and food impaction. The currently proposed pathophysiology is a combination of genetics, allergens, and epithelial barrier impairment. Diagnosis is reliant on history, endoscopic examination, and biopsy. Recent guidelines recognize the role of concurrent gastroesophageal reflux disease. Treatment is based on 3 paradigms: diet, drugs, and dilation. Drug therapy has historically focused on topical corticosteroids; as of 2022, dupilumab was approved for targeted biologic therapy. Dilation is reserved for symptomatic and anatomic management. As this clinical entity is better understood, additional therapies will hopefully be developed.

A Multicenter Long-Term Cohort Study of Eosinophilic Esophagitis Variants and Their Progression to Eosinophilic Esophagitis Over Time

INTRODUCTION

Eosinophilic esophagitis (EoE) variants have been recently characterized as conditions with symptoms of esophageal dysfunction resembling EoE, but absence of significant esophageal eosinophilia. Their disease course and severity have yet to be determined.

METHODS

Patients from 6 EoE centers with symptoms of esophageal dysfunction, but peak eosinophil counts of <15/hpf in esophageal biopsies and absence of gastroesophageal reflux disease with at least one follow-up visit were included. Clinical, (immuno)histological, and molecular features were determined and compared with EoE and healthy controls.

RESULTS

We included 54 patients with EoE variants (EoE-like esophagitis 53.7%; lymphocytic esophagitis 13.0%; and nonspecific esophagitis 33.3%). In 8 EoE-like esophagitis patients, EoE developed after a median of 14 months (interquartile range 3.6-37.6). Such progression increased over time (17.6% year 1, 32.0% year 3, and 62.2% year 6). Sequential RNA sequencing analyses revealed only 7 genes associated with this progression (with TSG6 and ALOX15 among the top 3 upregulated genes) with upregulation of a previously attenuated Th2 pathway. Immunostaining confirmed the involvement of eosinophil-associated proteins (TSG6 and ALOX15) and revealed a significantly increased number of GATA3-positive cells during progression, indicating a Th1/Th2 switch. Transition from one EoE variant (baseline) to another variant (during follow-up) was seen in 35.2% (median observation time of 17.3 months).

DISCUSSION

Transition of EoE variants to EoE suggests the presence of a disease spectrum. Few genes seem to be associated with the progression to EoE with upregulation of a previously attenuated Th2 signal. These genes, including GATA3 as a Th1/Th2 switch regulator, may represent potential therapeutic targets in early disease pathogenesis.

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.

The New Therapeutic Frontiers in the Treatment of Eosinophilic Esophagitis: Biological Drugs

Eosinophilic esophagitis (EoE) is a multifaceted disease characterized by a wide heterogeneity of clinical manifestations, endoscopic and histopathologic patterns, and responsiveness to therapy. From the perspective of an effective approach to the patient, the different inflammatory mechanisms involved in the pathogenesis of EoE and biologics, in particular monoclonal antibodies (mAbs), targeting these pathways are needed. Currently, the most relevant is dupilumab, which interferes with both interleukin (IL)-4 and IL-13 pathways by binding IL-4 receptor α, and is the only mAb approved by the European Medicine Agency and US Food and Drug Administration for the treatment of EoE. Other mAbs investigated include mepolizumab, reslizumab, and benralizumab (interfering with IL-5 axis), cendakimab and dectrekumab (anti-IL-13s), tezepelumab (anti-TSLP), lirentelimab (anti-SIGLEG-8), and many others. Despite the undeniable economic impact of biologic therapies, in the near future, there will be room for further reflection about the opportunity to prescribe biologic agents, not only as a last-line therapy in selected cases such as patients with comorbidities involving common pathways. Although recent findings are very encouraging, the road to permanent success in the treatment of EoE is still long, and further studies are needed to determine the long-term effects of mAbs and to discover new potential targets.

Benralizumab treatment in an elderly patient with eosinophilic esophagitis resulted in remission: a case report

BACKGROUND

Interleukin-5 (IL-5) has recently been shown to play a crucial role in eosinophil-mediated diseases, implying that an IL-5 receptor alpha chain (IL-5Rα) antibody (benralizumab) can be effective against eosinophilic esophagitis (EoE). Here, we present a case in which benralizumab significantly improved the symptoms and signs of an elderly Asian woman with EoE who had inadequate response to existing treatments. Case presentation A 73-year-old woman with an 8-year history of bronchial asthma (BA) and a 7-year history of dysphagia presented to our hospital with worsening dysphagia, vomiting, chest pain, and difficulty in eating. Blood biochemical findings revealed an increase in the eosinophil fraction of white blood cells (42.2%), and a conventional chest computed tomography scan revealed esophageal wall thickening. An upper gastrointestinal endoscopy revealed mucosal edema as well as multiple esophageal rings, and esophageal biopsy specimens showed an eosinophilic infiltrate of more than 15 cells/ high power field. Based on these findings, she was diagnosed as EoE complicated by BA. We firstly administrated 20 mg/day of prednisolone, rabeprazole sodium and liquid budesonide oral suspension for 5 months; however, they were ineffective and her dysphagia worsened over time. Then, benralizumab treatment in combination with these drugs was started. Her dysphagia completely disappeared 2 weeks after starting benralizumab, and an upper endoscopy showed that the clinical findings had completely disappeared after another 6 weeks. Benralizumab was then given to her for 41 months, and her symptoms remained in remission. In addition, she had no EoE recurrence for more than 12 months after discontinuing benralizumab.

CONCLUSIONS

Benralizumab in combination with other multiple drugs significantly improved the symptoms and examination findings of an elderly patients with EoE. Furthermore, she experienced no recurrence even after discontinuing benralizumab withdrawal, suggesting that benralizumab could be an appropriate therapeutic option for EoE.

Eosinophils-from cradle to grave: An EAACI task force paper on new molecular insights and clinical functions of eosinophils and the clinical effects of targeted eosinophil depletion

Over the past years, eosinophils have become a focus of scientific interest, especially in the context of their recently uncovered functions (e.g. antiviral, anti-inflammatory, regulatory). These versatile cells display both beneficial and detrimental activities under various physiological and pathological conditions. Eosinophils are involved in the pathogenesis of many diseases which can be classified into primary (clonal) and secondary (reactive) disorders and idiopathic (hyper)eosinophilic syndromes. Depending on the biological specimen, the eosinophil count in different body compartments may serve as a biomarker reflecting the underlying pathophysiology and/or activity of distinct diseases and as a therapy-driving (predictive) and monitoring tool. Personalized selection of an appropriate therapeutic strategy directly or indirectly targeting the increased number and/or activity of eosinophils should be based on the understanding of eosinophil homeostasis including their interactions with other immune and non-immune cells within different body compartments. Hence, restoring as well as maintaining homeostasis within an individual's eosinophil pool is a goal of both specific and non-specific eosinophil-targeting therapies. Despite the overall favourable safety profile of the currently available anti-eosinophil biologics, the effect of eosinophil depletion should be monitored from the perspective of possible unwanted consequences.

Barrier Dysfunction in Eosinophilic Esophagitis

PURPOSE OF REVIEW

Compelling evidence over the past decade supports the central role of epithelial barrier dysfunction in the pathophysiology of eosinophilic esophagitis (EoE). The purpose of this review is to summarize the genetic, environmental, and immunologic factors driving epithelial barrier dysfunction, and how this impaired barrier can further promote the inflammatory response in EoE.

RECENT FINDINGS

Common environmental exposures, such as detergents, may have a direct impact on the esophageal epithelial barrier. In addition, the effects of IL-13 on barrier dysfunction may be reduced by 17β-estradiol, Vitamin D, and the short chain fatty acids butyrate and propionate, suggesting novel therapeutic targets. There are many genetic, environmental, and immunologic factors that contribute to epithelial barrier dysfunction in EoE. This leads to further skewing of the immune response to a "Th2" phenotype, alterations in the esophageal microbiome, and penetration of relevant antigens into the esophageal mucosa, which are central to the pathophysiology of EoE.

Successful Treatment of Steroid-resistant Eosinophilic Gastrointestinal Disease with Mepolizumab

We experienced a case of treatment-resistant eosinophilic gastrointestinal disease (EGID). The patient, a 46-year-old man, presented with a fever, persistent abdominal pain, and an elevated peripheral eosinophil count. Eosinophil infiltration of the intestinal mucosa was also observed, and EGID was diagnosed. Corticosteroid therapy was initiated, but no improvement was seen. However, after mepolizumab (anti-interleukin 5 antibody) was administered, the patient's disease was controlled. Currently, the indications for mepolizumab are limited to bronchial asthma and paraneoplastic eosinophilic polyangiitis, but the experience herein reported suggests its usefulness in the treatment of EGID.

Comparison of drugs for active eosinophilic oesophagitis: systematic review and network meta-analysis

BACKGROUND

There is currently no recommendation regarding preferred drugs for active eosinophilic oesophagitis (EoE) because their relative efficacy is unclear. We conducted an up-to-date network meta-analysis to compare proton pump inhibitors, off-label and EoE-specific topical steroids, and biologics in EoE.

METHODS

We searched MEDLINE, Embase, Embase Classic and the Cochrane Central Register of Controlled Trials from inception to June 2023. We included randomised controlled trials (RCTs) comparing efficacy of all drugs versus each other, or placebo, in adults and adolescents with active EoE. Results were reported as pooled relative risks with 95% CIs to summarise effect of each comparison tested, with drugs ranked according to P score RESULTS: Seventeen RCTs were eligible for systematic review. Of these, 15 studies containing 1813 subjects with EoE reported extractable data for the network meta-analysis. For histological remission defined as ≤6 eosinophils/high-power field (HPF), lirentelimab 1 mg/kg monthly ranked first. For histological remission defined as ≤15 eosinophils/HPF, budesonide orally disintegrating tablet (BOT) 1 mg two times per day ranked first. For failure to achieve symptom improvement, BOT 1 mg two times per day and budesonide oral suspension (BOS) 2 mg two times per day were significantly more efficacious than placebo. For failure to achieve endoscopic improvement based on the EoE Endoscopic Reference Score, BOT 1 mg two times per day and BOS 1 mg two times per day or 2 mg two times per day were significantly more efficacious than placebo.

CONCLUSIONS

Although this network meta-analysis supports the efficacy of most available drugs over placebo for EoE treatment, significant heterogeneity in eligibility criteria and outcome measures among available trials hampers the establishment of a solid therapeutic hierarchy.

Mechanistic Insights into Eosinophilic Esophagitis: Therapies Targeting Pathophysiological Mechanisms

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease characterized by eosinophilic infiltration of the esophagus. It arises from a complex interplay of genetic predisposition (susceptibility loci), environmental triggers (allergens and dietary antigens), and a dysregulated immune response, mainly mediated by type 2 T helper cell (Th2)-released cytokines, such as interleukin (IL)-4, IL-5, and IL-13. These cytokines control eosinophil recruitment and activation as well as tissue remodeling, contributing to the characteristic features of EoE. The pathogenesis of EoE includes epithelial barrier dysfunction, mast cell activation, eosinophil degranulation, and fibrosis. Epithelial barrier dysfunction allows allergen penetration and promotes immune cell infiltration, thereby perpetuating the inflammatory response. Mast cells release proinflammatory mediators and promote eosinophil recruitment and the release of cytotoxic proteins and cytokines, causing tissue damage and remodeling. Prolonged inflammation can lead to fibrosis, resulting in long-term complications such as strictures and dysmotility. Current treatment options for EoE are limited and mainly focus on dietary changes, proton-pump inhibitors, and topical corticosteroids. Novel therapies targeting key inflammatory pathways, such as monoclonal antibodies against IL-4, IL-5, and IL-13, are emerging in clinical trials. A deeper understanding of the complex pathogenetic mechanisms behind EoE will contribute to the development of more effective and personalized therapeutic strategies.

Current and Novel Therapies for Eosinophilic Gastrointestinal Diseases

Eosinophilic gastrointestinal diseases (EGIDs) are an emerging group of pathological entities characterized by an eosinophil-predominant infiltration of different tracts of the gut in the absence of secondary causes of eosinophilia. According to the specific tract of the gut involved, EGIDs can be classified into eosinophilic esophagitis (EoE), eosinophilic gastritis (EoG), eosinophilic enteritis (EoN), and eosinophilic colitis (EoC). The epidemiology of EGIDs is evolving rapidly. EoE, once considered a rare disease, now has an incidence and prevalence of 7.7 new cases per 100,000 inhabitants per years and 34.4 cases per 100,000 inhabitants per year, respectively. Fewer data are available regarding non-EoE EGIDs, whose prevalence are estimated to range between 2.1 and 17.6 in 100,000 individuals, depending on age, sex, and ethnicity. Diagnosis requires the presence of suggestive symptoms, endoscopic biopsies showing abnormal values of eosinophils infiltrating the gut, and exclusion of secondary causes of eosinophilia. EoE typically presents with dysphagia and episodes of food bolus impactions, while EoG, EoN, and EoC may all present with abdominal pain and diarrhea, with or without other non-specific symptoms. In addition, although different EGIDs are currently classified as different entities, there may be overlap between different diseases in the same patient. Despite EGIDs being relatively novel pathological entities, the research on possible treatments is rapidly growing. In this regard, several randomized controlled trials are currently ongoing to investigate novel molecules, including ad-hoc steroid formulations, immunosuppressants, and mostly monoclonal antibodies that target the specific molecular mediators of EGIDs. This narrative review provides an up-to-date overview of available and investigational drugs for different EGIDs.

Mepolizumab for treatment of adolescents and adults with eosinophilic oesophagitis: a multicentre, randomised, double-blind, placebo-controlled clinical trial

OBJECTIVE

We aimed to determine whether mepolizumab, an anti-IL-5 antibody, was more effective than placebo for improving dysphagia symptoms and decreasing oesophageal eosinophil counts in eosinophilic oesophagitis (EoE).

METHODS

We conducted a multicentre, randomised, double-blind, placebo-controlled, trial. In the first part, patients aged 16-75 with EoE and dysphagia symptoms (per EoE Symptom Activity Index (EEsAI)) were randomised 1:1 to 3 months of mepolizumab 300 mg monthly or placebo. Primary outcome was change in EEsAI from baseline to month 3 (M3). Secondary outcomes included histological, endoscopic and safety metrics. In part 2, patients initially randomised to mepolizumab continued 300 mg monthly for 3 additional months (mepo/mepo), placebo patients started mepolizumab 100 mg monthly (pbo/mepo), and outcomes were reassessed at month 6 (M6).

RESULTS

Of 66 patients randomised, 64 completed M3, and 56 completed M6. At M3, EEsAI decreased 15.4±18.1 with mepolizumab and 8.3±18.0 with placebo (p=0.14). Peak eosinophil counts decreased more with mepolizumab (113±77 to 36±43) than placebo (146±94 to 160±133) (p<0.001). With mepolizumab, 42% and 34% achieved histological responses of <15 and ≤6 eos/hpf compared with 3% and 3% with placebo (p<0.001 and 0.02). The change in EoE Endoscopic Reference Score at M3 was also larger with mepolizumab. At M6, EEsAI decreased 18.3±18.1 points for mepo/mepo and 18.6±19.2 for pbo/mepo (p=0.85). The most common adverse events were injection-site reactions.

CONCLUSIONS

Mepolizumab did not achieve the primary endpoint of improving dysphagia symptoms compared with placebo. While eosinophil counts and endoscopic severity improved with mepolizumab at 3 months, longer treatment did not yield additional improvement.

TRIAL REGISTRATION NUMBER

NCT03656380.

Stem cell factor inhibition reduces Th2 inflammation and cellular infiltration in a mouse model of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a T helper (Th)2-mediated inflammatory disorder characterized endoscopically by eosinophilic infiltration leading to fibrosis of the esophagus. Stem cell factor (SCF), a multifunctional cytokine, is upregulated in several allergic diseases, including in patients with EoE. Mast cells and eosinophils express c-kit, the cell surface receptor for SCF, and have been found to play an important role in EoE. Therefore, we investigated whether blocking SCF represents a potential therapeutic approach for EoE. Esophageal inflammation was induced in mice using peanut allergen. In mice with experimental EoE, we found that SCF was upregulated in the esophageal tissue. In EoE mice injected with a polyclonal antibody specific for SCF, we observed a decrease in both mast cells and eosinophils by histological and flow cytometric analysis. Furthermore, Th2 cytokines in the esophagus were decreased in anti-SCF treated mice, as were levels of Th2 cytokines from lung-draining and esophageal lymph nodes. Serum levels of peanut-specific immunoglobulin E were reduced following treatment with anti-SCF. In Kitlf/f-Col1-Cre-ERT mice, which have SCF deleted primarily in myofibroblasts that develop in EoE, we observed similar results as the anti-SCF treated animals for inflammatory cell accumulation, cytokines, and histopathology. These results indicate that therapeutic treatments targeting SCF can reduce allergic inflammation in EoE.

A Practical Update on Pediatric Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is an emerging atopic disease of unknown etiology limited to the esophagus. The pathogenesis is still understood and is likely characterized by type 2 inflammation. Food allergens are the primary triggers of EoE that stimulate inflammatory cells through an impaired esophageal barrier. In children and adolescents, clinical presentation varies with age and mainly includes food refusal, recurrent vomiting, failure to thrive, abdominal/epigastric pain, dysphagia, and food impaction. Upper-gastrointestinal endoscopy is the gold standard for diagnosing and monitoring EoE. EoE therapy aims to achieve clinical, endoscopic, and histological ("deep") remission; prevent esophageal fibrosis; and improve quality of life. In pediatrics, the cornerstones of therapy are proton pump inhibitors, topical steroids (swallowed fluticasone and viscous budesonide), and food elimination diets. In recent years, much progress has been made in understanding EoE pathogenesis, characterizing the clinical and molecular heterogeneity, and identifying new therapeutic approaches. Notably, clinical, molecular, endoscopic, and histological features reflect and influence the evolution of inflammation over time and the response to currently available treatments. Therefore, different EoE phenotypes and endotypes have recently been recognized. Dupilumab recently was approved by FDA and EMA as the first biological therapy for adolescents (≥12 years) and adults with active EoE, but other biologics are still under consideration. Due to its chronic course, EoE management requires long-term therapy, a multidisciplinary approach, and regular follow-ups.

Personalized and Precision Medicine in Asthma and Eosinophilic Esophagitis: The Role of T2 Target Therapy

The role of type 2 inflammation has been progressively associated with many diseases, including severe asthma, atopic dermatitis, nasal polyposis, eosinophilic granulomatosis with polyangiitis, and, recently, eosinophilic esophagitis. Despite this, the association between asthma and esophagitis is still poorly known, and this is probably because of the low prevalence of each disease and the even lower association between them. Nonetheless, observations in clinical trials and, subsequently, in real life, have allowed researchers to observe how drugs acting on type 2 inflammation, initially developed and marketed for severe asthma, could be effective also in treating eosinophilic esophagitis. For this reason, clinical trials specifically designed for the use of drugs targeted to type 2 inflammation were also developed for eosinophilic esophagitis. The results of clinical trials are presently promising and envisage the use of biologicals that are also likely to be employed in the field of gastroenterology in the near future. This review focuses on the use of biologicals for type 2 inflammation in cases of combined severe asthma and eosinophilic esophagitis.

Recent Advances in the Treatment of Eosinophilic Esophagitis

Eosinophilic esophagitis is an increasingly common inflammatory allergic disease of the esophagus characterized by esophageal eosinophilia and symptoms of esophageal dysfunction. The therapeutic landscape has rapidly evolved for this emerging type 2 inflammatory disorder. We review traditional therapies including updates and expert opinions in addition to promising therapies on the horizon and the history of therapies that failed to meet end points and highlight knowledge gaps for future investigations.

The evolving landscape of immunotherapy for the treatment of allergic conditions

Allergic conditions, such as asthma, chronic urticaria, atopic dermatitis (AD), and eosinophilic esophagitis, have long been treated with oral and topical steroids which resulted in negative off-target effects. However, newer biologic medications are increasingly being developed and approved for treatment of these conditions. These medications have a variety of mechanisms of action to target pathophysiology specific to these diseases. As biologics become more targeted, fewer off-target effects are seen improving tolerability for patients as well as expanded options for treatment of these conditions. This review discusses monoclonal antibody therapies (omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, tezepelumab, and tralokinumab) including their safety and use in asthma, chronic urticaria, AD, and eosinophilic esophagitis.