Safety and Efficacy of Reslizumab for Children and Adolescents With Eosinophilic Esophagitis Treated for 9 Years

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.

Disproportionality analysis of reslizumab based on the FDA Adverse Event Reporting System

Background

With the increasing prescription of reslizumab for severe asthma with an eosinophilic phenotype, a real-world pharmacovigilance analysis of reslizumab is urgently required to detect potential unreported adverse events (AEs) in clinical practice.

Objectives

We aimed to provide a comprehensive evaluation of reslizumab-related AEs in the real world.

Design

Disproportionality analysis based on the FDA Adverse Event Reporting System (FAERS) database.

Methods

Reslizumab-related AEs between the second quarter of 2016 and the fourth quarter of 2022 from the FAERS database were obtained. A disproportionality analysis was performed to evaluate the safety profile of reslizumab using the reporting odds ratio.

Results

A total of 10,450,353 reports were collected from the FAERS database. Of the 403 reslizumab-related AEs, 42 distinct AEs were identified with positive signals. The most common AEs including dyspnea and oropharyngeal pain were identified, consistent with the instruction and clinical studies. Unexpected AEs of disproportionality such as bronchospasm and chest pain were also observed. Drug ineffective was identified as a noteworthy concern that accounted for 13.90% (56/403) of the overall reslizumab-related reports.

Conclusion

While reslizumab offered a promising treatment option for severe eosinophilic asthma, more attention should be paid to the common AEs and new unexpected AEs. Based on the current findings of signal detection, further prospective studies are needed for the next signal validation and confirmation.

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.

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.

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.

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.

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.

Medical treatment of eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic antigen-mediated eosinophilic inflammatory disease isolated to the esophagus. As a clinicopathologic disorder, a diagnosis of EoE requires a constellation of clinical symptoms of esophageal dysfunction and histologic findings (at least 15 eosinophils/high-powered microscope field (eos/hpf)). Current guidelines no longer require the failure of response to proton pump inhibitor medications to establish a diagnosis of EoE, but continue to suggest the exclusion of other etiologies of esophageal eosinophilia. The treatment goals for EoE are improvement in clinical symptoms, resolution of esophageal eosinophilia and other histologic abnormalities, endoscopic improvement, improved quality of life, improved esophageal function, minimized adverse effects of treatment, and prevention of disease progression and subsequent complications. Currently, there is no cure for EoE, making long-term treatment necessary. Standard treatment modalities include dietary modifications, esophageal dilation, and pharmacologic therapy. Effective pharmacologic therapies include corticosteroids, rapidly emerging biological therapies, and proton pump inhibitor medications.

OBJECTIVES

To evaluate the efficacy and safety of medical interventions for people with eosinophilic esophagitis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and WHO ICTRP to 3 March 2023.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing any medical intervention or food elimination diet for the treatment of eosinophilic esophagitis, either alone or in combination, to any other intervention (including placebo).

DATA COLLECTION AND ANALYSIS

Pairs of review authors independently selected studies and conducted data extraction and risk of bias assessment. We expressed outcomes as a risk ratio (RR) and as the mean or standardized mean difference (MD/SMD) with 95% confidence interval (CI). We assessed the certainty of the evidence using GRADE. Our primary outcomes were: clinical, histological, and endoscopic improvement, and withdrawals due to adverse events. Secondary outcomes were: serious and total adverse events, and quality of life.

MAIN RESULTS

We included 41 RCTs with 3253 participants. Eleven studies included pediatric patients while the rest recruited both children and adults. Four studies were in patients with inactive disease while the rest were in patients with active disease. We identified 19 intervention comparisons. In this abstract we present the results of the primary outcomes for the two main comparisons: corticosteroids versus placebo and biologics versus placebo, based on the prespecified outcomes defined of the primary studies. Fourteen studies compared corticosteroids to placebo for induction of remission and the risk of bias for these studies was mostly low. Corticosteroids may lead to slightly better clinical improvement (20% higher), measured dichotomously (risk ratio (RR) 1.74, 95% CI 1.08 to 2.80; 6 studies, 583 participants; number needed to treat for an additional beneficial outcome (NNTB) = 4; low certainty), and may lead to slightly better clinical improvement, measured continuously (standard mean difference (SMD) 0.51, 95% CI 0.17 to 0.85; 5 studies, 475 participants; low certainty). Corticosteroids lead to a large histological improvement (63% higher), measured dichotomously (RR 11.94, 95% CI 6.56 to 21.75; 12 studies, 978 participants; NNTB = 3; high certainty), and may lead to histological improvement, measured continuously (SMD 1.42, 95% CI 1.02 to 1.82; 5 studies, 449 participants; low certainty). Corticosteroids may lead to little to no endoscopic improvement, measured dichotomously (RR 2.60, 95% CI 0.82 to 8.19; 5 studies, 596 participants; low certainty), and may lead to endoscopic improvement, measured continuously (SMD 1.33, 95% CI 0.59 to 2.08; 5 studies, 596 participants; low certainty). Corticosteroids may lead to slightly fewer withdrawals due to adverse events (RR 0.64, 95% CI 0.43 to 0.96; 14 studies, 1032 participants; low certainty). Nine studies compared biologics to placebo for induction of remission. Biologics may result in little to no difference in clinical improvement, measured dichotomously (RR 1.14, 95% CI 0.85 to 1.52; 5 studies, 410 participants; low certainty), and may result in better clinical improvement, measured continuously (SMD 0.50, 95% CI 0.22 to 0.78; 7 studies, 387 participants; moderate certainty). Biologics result in better histological improvement (55% higher), measured dichotomously (RR 6.73, 95% CI 2.58 to 17.52; 8 studies, 925 participants; NNTB = 2; moderate certainty). We could not draw conclusions for this outcome when measured continuously (SMD 1.01, 95% CI 0.36 to 1.66; 6 studies, 370 participants; very low certainty). Biologics may result in little to no difference in endoscopic improvement, measured dichotomously (effect not estimable, low certainty). We cannot draw conclusions for this outcome when measured continuously (SMD 2.79, 95% CI 0.36 to 5.22; 1 study, 11 participants; very low certainty). There may be no difference in withdrawals due to adverse events (RR 1.55, 95% CI 0.88 to 2.74; 8 studies, 792 participants; low certainty).

AUTHORS' CONCLUSIONS

Corticosteroids (as compared to placebo) may lead to clinical symptom improvement when reported both as dichotomous and continuous outcomes, from the primary study definitions. Corticosteroids lead to a large increase in histological improvement (dichotomous outcome) and may increase histological improvement (continuous outcome) when compared to placebo. Corticosteroids may or may not increase endoscopic improvement (depending on whether the outcome is measured dichotomously or continuously). Withdrawals due to adverse events (dichotomous outcome) may occur less frequently when corticosteroids are compared to placebo. Biologics (as compared to placebo) may not lead to clinical symptom improvement when reported as a dichotomous outcome and may lead to an increase in clinical symptom improvement (as a continuous outcome), from the primary study definitions. Biologics lead to a large increase in histological improvement when reported as a dichotomous outcome, but this is uncertain when reported as a continuous outcome, as compared to placebo. Biologics may not increase endoscopic improvement (dichotomous outcome), but this is uncertain when measured as a continuous outcome. Withdrawals due to adverse events as a dichotomous outcome may occur as frequently when biologics are compared to placebo.

Current state of biologics in treating eosinophilic esophagitis

OBJECTIVE

Eosinophilic esophagitis (EoE) is a chronic, allergen-mediated, eosinophil-predominant, type 2 inflammatory disease that progresses to fibrostenosis of the esophagus if left untreated. This review focuses on biologics therapy in EoE.

DATA SOURCES

Manuscripts on EoE treatments are identified on PubMed.

STUDY SELECTIONS

Original research, randomized controlled trials, retrospective studies, meta-analyses, case series, and case reports of high relevance are selected and reviewed.

RESULTS

Biologics have been used as investigational therapies for EoE in clinical studies over the years, based on earlier work that identified key cytokines and mediators of eosinophilic inflammation and, more recently, type 2 inflammation that underlie EoE pathogenesis. Dupilumab, a monoclonal antibody that targets the interleukin (IL)-4Rα chain, thereby interfering with IL-4 and IL-13 binding with the receptor, was recently approved by the Food and Drug Administration for EoE. Dupilumab improved clinical symptoms, endoscopic scores, histologic inflammation, and esophageal distensibility. Several clinical trials that target key cytokines such as IL-5, IL-13, and thymic stromal lymphopoietin in EoE are still ongoing.

CONCLUSION

Topical corticosteroid, proton pump inhibitor therapy, elimination diet, and dilation are widely accepted treatment modalities for EoE. Dupilumab is the first Food and Drug Administration-approved therapy for EoE. Other studies evaluating biologics that target eosinophils, key cytokines, and inflammatory pathways in EoE are ongoing. Treatment algorithms are needed to position EoE therapies as they emerge.

Eosinophilic Gastrointestinal Diseases: The Pathogenesis, Diagnosis, and Treatment

Eosinophilic gastrointestinal diseases are delayed-type chronic allergic disorders that show gastrointestinal eosinophil dense infiltration, with an exaggerated Th2-type immune reaction considered to be an important mechanism. These diseases can be roughly divided into two types: eosinophilic esophagitis, mainly found in young and middle-aged men, and eosinophilic gastroenteritis, which is found in both genders equally. A diagnosis of eosinophilic esophagitis is suspected when characteristic endoscopic findings, including longitudinal furrows and rings, are noted. However, characteristic endoscopic abnormalities are rarely found in cases with eosinophilic gastroenteritis, so multiple biopsy sampling from the apparently normal gastrointestinal mucosal surface is important for making an accurate diagnosis. The administration of systemic glucocorticoid is the standard treatment for eosinophilic gastroenteritis, while acid inhibitors and topical glucocorticoid swallowing therapy are effective for eosinophilic esophagitis. Anti-cytokine therapies for eosinophilic gastrointestinal diseases are currently under development.

Biologics in eosinophilic gastrointestinal diseases

Eosinophilic gastrointestinal diseases are a constellation of conditions categorized by the location of eosinophilic infiltration in the gastrointestinal tract. Symptoms vary based on location of eosinophils and age of the patient. There are no approved medications at the current time with individuals using off-label steroids or dietary therapy. Translational research has identified potential pathways to target in the treatment of eosinophilic esophagitis (EoE), gastritis (EoG), and enteritis (EoN), including type 2 pathways, mast cells, and eosinophils. Preliminary studies found cendakimab (anti-interleukin [IL]-13) and dupilumab (anti-IL-4 receptor alpha) to have an effect on eosinophil count and symptoms with dupilumab recently approved. In addition, mepolizumab (anti-IL-5), reslizumab (anti-IL-5), and lirentelimab (anti-Siglec 8) were found to have reduction in eosinophils without reduction of symptoms. For EoG and EoN, both benralizumab (anti-IL-5 receptor) and lirentelimab were found to have histologic and symptom improvement. There are no agents studied for eosinophilic colitis. Results of ongoing phase 3 trials in EoE and EoG/EoN are also anticipated.

Eosinophilic esophagitis: Immune mechanisms and therapeutic targets

Eosinophilic esophagitis (EoE) is an emerging chronic inflammatory disease of the oesophagus and is clinically characterized by upper gastrointestinal (GI) symptoms including dysphagia and esophageal food impaction. Histopathologic manifestations, which include intraepithelial eosinophilic inflammation and alterations of the esophageal squamous epithelium, such as basal zone hyperplasia (BZH) and dilated intercellular spaces (DIS), are thought to contribute to esophageal dysfunction and disease symptoms. Corroborative clinical and discovery science-based studies have established that EoE is characterized by an underlying allergic inflammatory response, in part, related to the IL-13/CCL26/eosinophil axis driving dysregulation of several key epithelial barrier and proliferative regulatory genes including kallikrein (KLK) serine proteases, calpain 14 (CAPN14) and anoctamin 1 (ANO1). The contribution of these inflammatory and proliferative processes to the clinical and histological manifestations of disease are not fully elucidated. Herein, we discuss the immune molecules and cells that are thought to underlie the clinical and pathologic manifestations of EoE and the emerging therapeutics targeting these processes for the treatment of EoE.

Current and emerging biologic therapies targeting eosinophilic disorders

Eosinophilic disorders include a wide array of conditions in which eosinophils play a primary pathophysiologic role. While historically treated with corticosteroids and immunosuppressants, knowledge of eosinophil biology has led to the development of several biologics targeting eosinophils. In this review, we discuss the current US Food and Drug Administration (FDA) approved eosinophil-specific biologics targeting IL-5 (mepolizumab and reslizumab) and IL-5R (benralizumab) along with biologics under investigation targeting siglec-8 (lirentelimab). We discuss efficacy and safety data from trials of these medications in conditions including eosinophilic asthma, hypereosinophilic syndrome (HES), eosinophilic granulomatosis with polyangiitis (EGPA), chronic rhinosinusitis with nasal polyposis (CRSwNP), eosinophilic esophagitis (EoE), and eosinophilic gastrointestinal disease (EGID). Additionally, we discuss case reports utilizing these medications in conditions including drug reaction with eosinophilia and systemic symptoms (DRESS), allergic bronchopulmonary aspergillosis (ABPA), and eosinophilic pneumonia, among others. While eosinophilic targeting biologic therapy has been successful in eosinophilic asthma, HES, EGPA, and CRSwNP leading to FDA approval for these conditions, trials treating EoE and EGID have been disappointing to date. Given the increasing number of trials utilizing these biologics, it will be imperative for the allergist-immunologist to stay up to date on the latest treatment options to provide the most optimal care for eosinophilic disorders.

Examining the Role of Type 2 Inflammation in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic type 2 inflammatory disease characterized by an eosinophilic inflammatory infiltrate in the esophagus, leading to remodeling, stricture formation, and fibrosis. Triggered by food and aeroallergens, type 2 cytokines interleukin (IL)-4, IL-13, IL-5 produced by CD4+ T helper 2 cells (Th2), eosinophils, mast cells, basophils, and type 2 innate lymphoid cells alter the esophageal epithelial barrier and increase inflammatory cell tissue infiltration. Clustering analysis based on the expression of type 2 inflammatory genes demonstrated the diversity of EoE endotypes. Despite the availability of treatment options for patients with EoE, which include dietary restriction, proton pump inhibitors, swallowed topical steroids, and esophageal dilation, there are still no Food and Drug Administration-approved medications for this disease; as such, there are clear unmet medical needs for these patients. A number of novel biologic therapies currently in clinical trials represent a promising avenue for targeted therapeutic approaches in EoE. This review summarizes our current knowledge on the role of type 2 inflammatory cells and mediators in EoE disease pathogenesis, as well as the future treatment landscape targeting underlying inflammation in EoE.

Current and emerging therapies for eosinophilic esophagitis

Background: Eosinophilic esophagitis (EoE) is a Type-2 chronic inflammatory food antigen-driven disease of the esophagus, characterized by eosinophilic predominant inflammation and a constellation of symptoms. The incidence and prevalence of EoE has increased over the past 2 decades. There is an unmet need for approved less burdensome treatment options. Objective: To describe the underlying pathophysiology and diagnosis of EoE and discuss the currently available treatment options. We also aim to review the new and emerging therapies for EoE. Methods: A search of a medical literature data base was performed for articles that discuss treatment for EoE. Results: A comparison of current therapies showed that dietary elimination, swallowed topical corticosteroids, and proton-pump inhibitor therapy are all effective for different populations. Emerging therapies that were reviewed include new topical corticosteroids and biologics directed against Type 2 inflammation. Conclusion: EoE is a chronic inflammatory disorder that can be debilitating, with long-term sequelae. There are no current approved therapies in the United States. Numerous new treatments are on the horizon. Increasing amounts of data are helping to tailor treatment for each patient. Ultimately, shared decision-making is the best approach to guide treatment choices with patients to manage the ever-increasing burden of this disease.

An Overview of Off-Label Use of Humanized Monoclonal Antibodies in Paediatrics

In recent years, off-label and unlicensed drug use has extensively developed in the paediatric population. For a long time, clinical trials in the paediatric population were considered complicated to perform because of ethical problems, causing frequent off-label use. Off-label drug use remains an important public health issue, especially for children with rare conditions or with diseases not responsive to conventional treatments. The present paper is a narrative review of the literature of off-label drug use in children. The aim of our study is to summarize the main works dealing with the off-label use of biological drugs in paediatrics. Further studies analyzing their efficacy, safety, and cost-benefit ratios are needed to extend the use of biological therapies to the paediatric population.

Type 2 Inflammation in Eosinophilic Esophagitis: From Pathophysiology to Therapeutic Targets

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease of the esophagus characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation, whose incidence is rising. It significantly affects patients’ quality of life and, if left untreated, results in fibrotic complications. Although broad consensus has been achieved on first-line therapy, a subset of patients remains non-responder to standard therapy. The pathogenesis of EoE is multifactorial and results from the complex, still mostly undefined, interaction between genetics and intrinsic factors, environment, and antigenic stimuli. A deep understanding of the pathophysiology of this disease is pivotal for the development of new therapies. This review provides a comprehensive description of the pathophysiology of EoE, starting from major pathogenic mechanisms (genetics, type 2 inflammation, epithelial barrier dysfunction, gastroesophageal reflux, allergens, infections and microbiota) and subsequently focusing on the single protagonists of type 2 inflammation (involved cells, cytokines, soluble effectors, surface proteins and transcription factors) that could represent present and future therapeutic targets, while summarizing previous therapeutic approaches in literature.

Pathophysiology of Non-IgE-Mediated Food Allergy

Non-IgE-mediated food allergies are a group of disorders characterized by subacute or chronic inflammatory processes in the gut. Unlike IgE mediated food allergies that may result in multi-organ system anaphylaxis, the non-IgE mediated food allergies primarily affect the gastrointestinal tract. This review outlines the clinical manifestations, epidemiology, pathophysiology, and management of non-IgE-mediated food allergies. An updated literature search of selected non-IgE-mediated food allergies was conducted for this review using PubMed database to the current year (2021). Reviewed disorders include food protein-induced enterocolitis syndrome (FPIES), food-protein enteropathy (FPE), food protein-induced allergic proctocolitis (FPIAP), and eosinophilic gastrointestinal disorders (EGIDs) such as eosinophilic esophagitis (EoE). While extensive gains have been made in understanding FPIES, FPIAP, FPE, and EoE, more information is needed on the pathophysiology of these food allergies. Similarities among them include involvement of innate immunity, T-lymphocyte processes, alteration of the intestinal lumen at the cellular level with the appearance of inflammatory cells and associated histologic changes, and specific cytokine profiles suggesting food-specific, T-cell, and immune-mediated responses. While FPIES and FPIAP typically resolve in early childhood, EGIDs typically do not. Emerging new therapies for EoE offer promise of additional treatment options. Further studies identifying the immunopathogenesis, associated biomarkers, and mechanisms of tolerance are needed to inform prevention, diagnosis and management.

Pediatric eosinophilic esophagitis: a review for the clinician

Eosinophilic esophagitis (EoE) is a chronic clinical-pathologic disease characterized by eosinophilic infiltration of the esophageal epithelium with esophageal dysfunction symptoms.EoE can occur at any age and has different clinical manifestations depending on the age onset.To date, esophago-gastroduodenal endoscopy (EGD) with biopsy is the gold-standard for EoE diagnosis.According to the recent consensus guidelines, proton pump inhibitors, corticosteroids and elimination diets could be a first-line therapy option. The aim of the treatment is clinical and histological remission for preventing long-lasting untreatable fibrosis.A multidisciplinary approach (allergist, gastroenterology, dietitian, and pathologist) is recommended for managing patients affected by EoE, given the complexity of its treatment.This review will provide a practical guide to assist pediatricians treating children with EoE.Moreover, it highlights the unmet needs in diagnosis and treatment that require urgent attention from the scientific community in the aim of improving the management of patients with EoE.

Reduction/elimination of blood eosinophils in severe asthma: should there be a safety consideration?

INTRODUCTION

Eosinophils play a central role in the inflammation of asthma and are the target of new biologic treatments for patients with severe asthma. Biologics targeting the IL-5 pathway have been shown to reduce asthma exacerbations, improve lung function, reduce oral corticosteroid use, and improve quality of life, accompanied by reduced or even eliminated blood eosinophils. Eosinophils have been associated with host protection and tumor growth, raising potential concerns about the consequences of these long-term therapies that reduce or eliminate them.

AREAS COVERED

In this review, we explore the current safety profile of biologics regarding the impact they may have on blood eosinophils, trying to answer the question about any safety consideration.

EXPERT OPINION

Eosinophils have been associated with host protection and tumor growth, raising potential concerns about the consequences of long-term therapies that reduce or eliminate these blood cells.

Emerging Therapies for Eosinophilic Gastrointestinal Diseases

Besides eosinophilic esophagitis, other eosinophilic gastrointestinal diseases (EGIDs), such as eosinophilic gastritis, eosinophilic gastroenteritis, and eosinophilic colitis, are increasingly diagnosed over the last decade. Whereas diagnosis and therapy of eosinophilic esophagitis have been standardized, the diagnosis and therapy of other EGIDs are areas of active research. Motivated by the increasing prevalence of these conditions, concerted efforts of different stakeholders have led to the evaluation of targeted biologic therapies for EGID management over the last couple of years, and several promising molecules are currently in the pipeline. This review article provides an overview of targeted biologic therapies for use in EGIDs.

The use of biologics in food allergy

BACKGROUND

Food allergy continues to pose problems due to its increased frequency and its increasingly high severity. In this context, alongside the traditional avoidance strategies of allergenic foods and desensitization through the cautious progression of exposure to foods in the context of oral immunotherapy (OIT), alternative strategies have made their way in the last decades. We review the possibilities of intervention in food allergy with the use of biological drugs capable of interfering with the synthesis of IgE, with their mechanisms of action, or with complex biological mechanisms that lead to the establishment of a food allergy.

METHODS

Repeated Entrez PubMed searches using the template algorithm "Food allergy" and "biologics" or "Omalizumab" or "Dupilumab" or "milk desensitization" or "oral tolerance induction" or "oral immunotherapy" or "Etokimab" or "Tezepelumab" or "Quilizumab" or "Ligelizumab" or "Tralokinumab" or "Nemolizumab" or "Mepolizumab" or "Reslizumab" or "Benralizumab". The authors' clinical experience in paediatric allergy units of University hospitals was also drawn upon.

RESULTS

The landscape in this context has changed dramatically over the past 10 years. We have acquired knowledge mainly on the effect of different types of anti-IgE treatments in poliallergic patients with food allergy, and in patients treated with OIT. However, other mediators are being targeted by specific biologic treatments. Among them, the alarmins Il-33 and TSLP, IL-4 and IL-13, eosinophil-related molecules as IL-6, IL-8, IL-10, IL-12, and mostly IL-5, and integrins involved in the pathogenesis of eosinophilic gastrointestinal diseases (EGIDs), as SIGLEC-8.

CONCLUSIONS

The ever-better knowledge of the mechanisms of food allergy allowing these developments will improve not only the perspective of patients with the most serious immediate food allergies such as anaphylaxis, but also those of patients with related diseases such as atopic dermatitis, eosinophilic esophagitis, and EGIDs. Biologics are also intended to complement OIT strategies that have developed over the years.

Eosinophilic esophagitis. What diet? How to treat it? The point of view of a gastroenterologist working in a department of allergology

Eosinophilic esophagitis (EoE) belongs to a broad group of allergic gastrointestinal diseases. More narrowly, it is classified as an eosinophilic gastrointestinal disease and is its most common representative. Until recently, this disease was extremely rare, but the last 3 decades have seen a rapid increase in its prevalence to such an extent that in some recent studies it has been named the most common esophageal disease after reflux disease. EoE is an interdisciplinary disorder on the borderline between gastrointestinal and allergologic diseases, requiring cooperation of these two branches of medicine in diagnostics and treatment. Despite the development of medical science it remains a poorly known disease, difficult to diagnose and even more difficult to treat. Recent years have seen the emergence of new studies and guidelines, both American and European, that have radically changed our approach to the diagnosis and treatment of EoE.

Targeted Therapies for Eosinophilic Gastrointestinal Disorders

The growing recognition of eosinophilic gastrointestinal disorders has revealed the limitations of current treatment (mainly based on dietary modification and corticosteroids), and include refractoriness, high recurrence rates, and the need for long-term therapy. Research efforts, mainly in eosinophilic esophagitis (EoE), have unveiled essential pathophysiological mechanisms leading to these disorders, which bear some similarities to those of atopic manifestations and are shared by eosinophilic gastroenteritis (EGE) and eosinophilic colitis (EC). Novel targeted therapies, some imported from bronchial asthma and atopic dermatitis, are currently being assessed in EoE. The most promising are monoclonal antibodies, including those targeting interleukin (IL)-13 (cendakimab) and IL-4 (dupilumab), with phase 3 trials currently ongoing. The potential of anti-integrin therapy (vedolizumab) and Siglec-8 blockers (antolimab) in EGE are also promising. Non-biological therapies for eosinophilic gut disorders, which include preventing the activation of Janus kinase (JAK)-signal transducer and activator of transcription (STAT) and chemoattractant receptor expressed on T helper 2 cells (CRTH2) signaling pathways, and other potential targets that deserve investigation in eosinophilic gut disorders, are reviewed.

Long-term Efficacy and Tolerability of RPC4046 in an Open-Label Extension Trial of Patients With Eosinophilic Esophagitis

BACKGROUND & AIMS

The short-term efficacy of RPC4046, a monoclonal antibody against interleukin-13, has been shown in patients with eosinophilic esophagitis (EoE). We investigated the long-term efficacy and safety of RPC4046 in an open-label, long-term extension (LTE) study in adults with EoE.

METHODS

We analyzed data from 66 patients who completed the 16-week, double-blind, induction portion of a phase 2 study of RPC4046 (180 mg or 360 mg/wk) vs placebo and then completed a 52-week LTE, receiving open-label RPC4046 360 mg/wk. The study was conducted at 28 centers in 3 countries; patients were enrolled between September 2014 and January 2017. Outcomes were stratified by double-blind dose group and included esophageal eosinophil counts, EoE endoscopic reference score, EoE histologic scoring system score, symptom-based EoE activity index score, and safety.

RESULTS

By week 12 of the LTE, esophageal eosinophil mean and peak counts, total EoE endoscopic reference scores, and EoE histologic scoring system grade and stage scores did not differ considerably between patients who originally received placebo vs RPC4046. Most patients maintained responses through week 52. Symptom remission (symptom-based EoE activity index score, ≤20) increased from 14% at LTE entry to 67% at LTE week 52 in placebo‒RPC4046 patients and from 30% to 54% in RPC4046‒RPC4046 (either dose) patients. Of the 28 patients who did not have a histologic response to RPC4046 during the double-blind induction phase, 10 patients (36%) achieved response during the LTE. The most common adverse events were upper respiratory tract infection (21%) and nasopharyngitis (14%).

CONCLUSIONS

One year of treatment with RPC4046 is generally well tolerated and results in continued improvement and/or maintenance of endoscopic, histologic, and clinical measures of EoE disease activity relative to baseline.

TRIAL REGISTRATION

NCT02098473.

Eosinophilic esophagitis: from pathophysiology to management

Eosinophilic esophagitis (EoE) incidence and prevalence have sharply increased in the last decade; so, the management of these patients is changing rapidly. Standard regimens as elimination diet, proton pump inhibitors and topical swallowed steroids are not able to achieve remission in all patients. Moreover, loss of efficacy and safety concerns for long-term medical treatments are rising questions. As for other chronic immune-mediated diseases, biologics have been evaluated for the treatment of EoE. Several targets in the Th2-mediated inflammatory cascade with eosinophilic mucosal infiltration, have been tested with alternating results. This review provides a comprehensive discussion of the available studies evaluating biologics in EoE and the possible future options most desirable for these patients.

Eosinophilic Esophagitis: Update on Diagnosis and Treatment in Pediatric Patients

Eosinophilic esophagitis (EoE) is a chronic immune-mediated inflammatory disorder characterized by symptomatic esophageal dysfunction and an eosinophil-predominant inflammation of the esophagus. EoE arises from interaction between genetic and environmental factors. In pediatric patients, clinical manifestations vary depending on age, from a gastroesophageal reflux disease (GERD)-like condition to severe dysphagic symptoms. Upper endoscopy is considered the gold standard for diagnosis and monitoring of EoE; however, significant efforts are underway to identify noninvasive diagnostic tools and biomarkers to avoid repetitive invasive procedures. Therapeutic first-line options currently available for EoE are elimination diets, proton pump inhibitors (PPIs), and steroids. The aim of treatment is to improve clinical symptoms while obtaining mucosal healing and avoiding long-term complications. Dietary treatment options comprise different empiric diets or an exclusively amino acid formula. Despite the efficacy of diets, compliance is often challenging. PPIs and topical steroids represent the main pharmacological options for EoE, and both can induce and maintain remission. Topical steroids have been reported as more effective, but data on long-term safety remain insufficient for both these and PPIs. Endoscopic dilations are currently reserved for severe untreated fibrostenotic disease unresponsive to medical therapies. Several biologic agents are available but not yet approved for EoE.

Infectious Implications of Interleukin-1, Interleukin-6, and T Helper Type 2 Inhibition

Targeting interleukins that drive innate inflammation has expanded treatments of autoinflammatory and autoimmune disorders. Interleukin (IL)-1 inhibition has proven useful for monogenic autoinflammatory syndromes, and IL-6 inhibition for autoimmune arthritides. Biological therapies impeding these pathways impair detection and containment of pathogens, particularly invasive bacteria, reflecting the importance of IL-1 and IL-6 in communicating danger throughout the immune system. Biologics targeting T helper type 2 inflammation are used to treat specific allergic, atopic, and eosinophilic diseases. They may impair protections against local herpesvirus reactivations while augmenting antiviral responses to respiratory viruses. Their risks with helminth exposures have yet to be defined.

The Role of the Environment in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammatory disease with incompletely understood pathogenesis. Though disease manifestations were initially ascribed to a delayed reaction to food allergens, emerging evidence suggests that modifiable host factors and environmental allergen exposure may also play critical roles in the pathogenesis and ongoing manifestations of EoE. As with other atopic diseases, lack of early-life exposure to microbial pathogens leads to an immune tolerance defect and reprograms the commensal gut microflora toward a type 2 T helper (Th2) phenotype; the esophageal microbiota, a rich environment consisting of diverse bacterial species, is greatly altered by inflammation. Although multiple early life microbiome-altering factors are associated with EoE development, no causative, direct relationships have been identified. Interestingly, large, cross-sectional analyses of several populations identify an inverse relationship between Helicobacter pylori presence and EoE, likely via virulence factors that downregulate Th2 inflammation, though causality has not been proven. In regard to environmental allergens, some studies support seasonal variation in EoE diagnosis and flares, and EoE can be generated after a large, identifiable aeroallergen exposure. Examples include mouse models of intranasal Aspergillus dosing and following initiation of oral immunotherapy to foods or environmental allergens. Conversely, treatment of allergic rhinoconjunctivitis may improve EoE symptoms, though data is limited to case reports and small series. Unfortunately, biologic therapies for atopic conditions have failed to improve EoE symptoms despite improvement in esophageal eosinophil count, though dupilumab shows promise in ongoing studies. Overall, this chapter shows that EoE pathogenesis is likely multifactorial, and the environment is a key component in our understanding of EoE.

The Role of the Environment in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammatory disease with incompletely understood pathogenesis. Though disease manifestations were initially ascribed to a delayed reaction to food allergens, emerging evidence suggests that modifiable host factors and environmental allergen exposure may also play critical roles in the pathogenesis and ongoing manifestations of EoE. As with other atopic diseases, lack of early-life exposure to microbial pathogens leads to an immune tolerance defect and reprograms the commensal gut microflora toward a type 2 T helper (Th2) phenotype; the esophageal microbiota, a rich environment consisting of diverse bacterial species, is greatly altered by inflammation. Although multiple early life microbiome-altering factors are associated with EoE development, no causative, direct relationships have been identified. Interestingly, large, cross-sectional analyses of several populations identify an inverse relationship between Helicobacter pylori presence and EoE, likely via virulence factors that downregulate Th2 inflammation, though causality has not been proven. In regard to environmental allergens, some studies support seasonal variation in EoE diagnosis and flares, and EoE can be generated after a large, identifiable aeroallergen exposure. Examples include mouse models of intranasal Aspergillus dosing and following initiation of oral immunotherapy to foods or environmental allergens. Conversely, treatment of allergic rhinoconjunctivitis may improve EoE symptoms, though data is limited to case reports and small series. Unfortunately, biologic therapies for atopic conditions have failed to improve EoE symptoms despite improvement in esophageal eosinophil count, though dupilumab shows promise in ongoing studies. Overall, this chapter shows that EoE pathogenesis is likely multifactorial, and the environment is a key component in our understanding of EoE.

Pharmacological treatments for eosinophilic esophagitis: current options and emerging therapies

Introduction: The epidemiology of eosinophilic esophagitis (EoE) has increased rapidly to represent a common cause of chronic and recurrent esophageal symptoms. Current treatment options have limitations so the development of novel therapies is a matter of growing interest.Areas covered: This article provides an up-to-date discussion of current therapies and investigational options for EoE. Established anti-inflammatory treatments for EoE at present include dietary therapy, proton pump inhibitors and swallowed topic steroids, which should be combined with endoscopic dilation in case of strictures. Refractoriness, high recurrence rates, and need for long-term therapies have promoted the investigation of novel, esophageal-targeted formulas of topic corticosteroids, and monoclonal antibodies (including mepolizumab, reslizumab, QAX576, RPC4046, dupilumab, omalizumab, infliximab, and vedolizumab) for EoE, with some having been demonstrated as effective and safe in the short term. Several additional promising therapies are also discussed.Expert opinion: Several therapeutic targets have shown efficacy and will be approved to treat EoE, especially corticosteroid-sparing options and those for patients with multiple Th2-associated diseases. Personalized therapeutic strategies for initial and maintenance treatments of EoE must be rationally designed, to reduce the burden of disease and answer meaningfully the needs of all stakeholders involved in EoE.

Critical Points on the Use of Biologicals in Allergic Diseases and Asthma

Improved understanding of the contribution of immune-inflammatory mechanisms in allergic diseases and asthma has encouraged development of biologicals and small molecules specifically targeting the innate and adaptive immune response. There are several critical points impacting the efficacy of this stratified approach, from the complexity of disease endotypes to the effectiveness in real-world settings. We discuss here how these barriers can be overcome to facilitate the development of implementation science for allergic diseases and asthma.

Emerging therapies for eosinophilic esophagitis

Despite advances in the pathologic understanding of eosinophilic esophagitis (EoE), as of yet, no single agent has been approved by the US Food and Drug Administration to treat EoE. Off-label, EoE is currently treated by using the 3 Ds: drugs (particularly swallowed topical corticosteroids), dietary restriction, and endoscopic dilation. In the recent past, considerable progress in terms of EoE treatment has been made: (1) new EoE-specific steroid formulations optimizing mucosal deposition have been developed, which has culminated in recent approval of a budesonide effervescent tablet in Europe; (2) biologics used for other T_H2-mediated diseases, such as allergic asthma and atopic eczema, as well as purpose-developed biologics, have been studied in phase II trials in patients with EoE; and (3) novel dietary restriction strategies have evolved. Finally, further insights into the pathogenesis of EoE have revealed several novel disease mediators that might be targeted in the future. In the following article we will discuss recent advances in EoE treatment with regard to swallowed topical steroids, biological agents, dietary approaches, and novel molecular targets.

Eosinophilic esophagitis: Current concepts in diagnosis and treatment

Eosinophilic esophagitis is an immune-allergic pathology of multifactorial etiology (genetic and environmental) that affects both pediatric and adult patients. Its symptoms, which include heartburn, regurgitation, and esophageal stenosis (with dysphagia being more frequent in eosinophilic esophagitis in young adults and children), are similar to those of gastroesophageal reflux disease, causing delays in diagnosis and treatment. Although endoscopic findings such as furrows, esophageal mucosa trachealization, and whitish exudates may suggest its presence, this diagnosis should be confirmed histologically based on the presence of more than 15 eosinophils per high-power field and the exclusion of other causes of eosinophilia (parasitic infections, hypereosinophilic syndrome, inflammatory bowel disease, among others) for which treatment could be initiated. Currently, the 3 “D”s (“Drugs, Diet, and Dilation”) are considered the fundamental components of treatment. The first 2 components, which involve the use of proton pump inhibitors, corticosteroids, immunosuppressants and empirical diets or guided food elimination based on allergy tests, are more useful in the initial phases, whereas endoscopic dilation is reserved for esophageal strictures. Herein, the most important aspects of eosinophilic esophagitis pathophysiology will be reviewed, in addition to evidence for the various treatments.

Targeting eosinophils: severe asthma and beyond

Recent research in the field of bronchial asthma has mainly focused on eosinophilic disease phenotype. Several trials proved the efficacy and safety profile of eosinophils and interleukin (IL)-5 targeting molecules, currently approved for severe asthma and available on the market. They include mepolizumab and reslizumab, IL-5 blocking molecules, and benralizumab, targeting the IL-5 receptor and eliciting a NK cell-mediated antibody-dependent cellular cytotoxicity against eosinophils. Eosinophilic inflammation represents the common pathophysiological background of several conditions, providing the rationale for the use of the same biologics beyond asthma. Although with different evidence grade, from clinical trials to case reports, anti-IL-5 biologics have been investigated in eosinophilic granulomatosis with polyangitis, allergic bronchopulmonary aspergillosis, chronic eosinophilic pneumonia, nasal polyposis, hypereosinophilic syndrome, and eosinophilic esophagitis. However, non-negligible differences between asthma and other eosinophilic diseases, particularly in eosinophils homing (blood and/or tissues), target organs and thus clinical features, probably account for the different response to the same drug in different clinical conditions and highlights the need for tailoring the therapeutic approach by modulating the drug dose and/or by combination therapy with multiple drugs. The optimal safety and tolerability profile of anti-IL-5 drugs warrants further and larger experimental and real-life investigations, which are needed especially in the field of non-asthma eosinophilic diseases. This review aims at summarizing the rationale for the use of biologics in eosinophilic diseases and their mechanisms of action. The current efficacy and safety evidence about eosinophils and IL-5 targeting molecules in asthma and in eosinophilic conditions beyond bronchi is also discussed.

Eosinophilic esophagitis in children: current knowledge to open new horizons

Eosinophilic Esophagitis (EoE) is a chronic immune/antigen-mediated condition which is also driven by genetic and environmental factors. It has been deeply investigated over the last years and its incidence is widely increasing in childhood. Although atopic diseases are closely linked with EoE, it does not recognize a classical IgE-mediate immune pathogenesis but it is rather a T helper type 2 inflammatory process. Familial clustering supports genetic predisposition in EoE and recent advances in understanding the genetic basis for EoE may eventually translate into targeted management of the disease. EoE diagnosis is based on clinical symptoms, micro, and macroscopic findings along with exclusion of gastroesophageal reflux disease (GERD) evidence. Management of the disease encompasses both dietary and pharmacological solutions that need to be specifically targeted on patients' history, clinical symptoms, and diagnostic evaluations. New therapies, currently not available in children, may represent the basis for future therapeutic options in the next years.

Molecular basis and cellular mechanisms of eosinophilic esophagitis for the clinical practice

Eosinophilic esophagitis (EoE) is a chronic, allergen-driven inflammatory esophageal disease characterized by predominantly eosinophilic inflammation leading to esophageal dysfunction. Recent efforts to understand EoE have increased our knowledge of the disease. Areas covered: Multiple cells, molecules, and genes interplay with early life environmental factors in the pathophysiology of EoE to converge in the esophageal epithelium at the center of disease pathogenesis. Epithelial cells constitute a mayor cytokine source for TSLP and Calpain-14; an impaired epithelial barrier function allowing penetration of food and microbiota-derived antigens is involved in triggering and maintaining inflammation. Eosinophil and mast cell-derived products, including TGFβ, together with IL-1β and TNFα, promote epithelial mesenchymal transition in EoE, contributing to tissue remodeling by synthetizing and depositing extracellular matrix in subepithelial layers. This article aims to provide a state-of-the-art update on the pathophysiology of EoE applied to clinical practice, and latest research and developments with potential interest to improve the diagnosis and treatment of patients with EoE are revised. Expert commentary: Preliminary approaches have provided promising results toward incorporating minimally invasive methods for patient diagnosis and monitoring in clinical practice. Early diagnosis and optimized therapies will allow for personalized medicine in EoE.

Current State and Future of Biologic Therapies in the Treatment of Asthma in Children

There is increasing recognition of phenotypic variability in pediatric asthma, providing the opportunity for a more personalized approach to therapy. Increasingly biologic therapies, in particular those targeting the "allergic" (or T helper 2) pathway, are being considered for children with severe asthma. However, there is a great deal of variability in the extent these biologic therapies have been studied in children, as well as efficacy of results thus far. The goal of this article is to review the mechanism of action, efficacy, and potential predictive and monitoring biomarkers of the biologic medications focusing on the pediatric population, in an effort to establish a more personalized approach to asthma in the pediatric population for the 21st century.

Systematic review of histological remission criteria in eosinophilic esophagitis

Elemental diets, dietary elimination, and steroid therapies are the most common therapies in the clinical trials for eosinophilic esophagitis (EoE). Histological findings (usually reported as eosinophils per microscopic high‐powered field [hpf]) remain the most common end‐point used to define response. Yet, the threshold for defining “response” and “remission” are ill‐defined among consensus guidelines and may vary from study to study. We conducted a systematic literature review of articles on eosinophilic esophagitis, published between January 2007 and November 2017, considering histological remission as the primary outcome. We abstracted treatment information and definitions of histological remission or response. A comparison of definitions of histological remission across and within institutions was performed. A total of 61 articles were included in this review, with approximately 60% of the studies published from centers in the United States. Histological definitions of remission of EoE ranged from 0 to ≤20 eosinophils/hpf. The most stringent criteria, ranging from 0 to ≤5 eosinophils/hpf, were commonly used in interventional trial studies that examined the effects of new treatments. We found remarkable variability in definitions between studies, treatment types, and regions. Age or epidemiological distribution of study subjects did not influence the criteria for histological remission. Clinical and histological improvements are important measures of the effects of treatment. Histological findings, the most objective measure of treatment, should provide an optimal method for comparing the effectiveness of various treatments. Yet, our findings suggest a lack of consistent remission criteria in published studies. Considering these inconsistencies, it is difficult to compare the effectiveness of various treatments.

Emerging drugs for eosinophilic esophagitis

INTRODUCTION

Eosinophilic esophagitis (EoE) is rare but incidence and prevalence is increasing. EoE is characterized by eosinophilic inflammation of the esophagus causing gastrointestinal symptoms such as abdominal pain, vomiting, reflux, dysphagia, and food impactions. If untreated, remodeling and fibrosis of the esophagus can occur and stricture formation may result. Current treatment options are limited to food-restriction diets or medications including proton pump inhibitors (PPIs) or swallowed corticosteroids. Significant progress has been made in understanding the underlying mechanisms of EoE allowing for development of drugs that target specific points in EoE pathways. Investigation of these drugs is early with few controlled studies, but many show promise as future treatments. Areas covered: This review will provide an up to date discussion of current therapies and investigational drugs for EoE. Articles used in this review were retrieved from PubMed. Ongoing or completed clinical trials were obtained through clinicaltrials.gov and review of the PharmaProjects database. Expert Opinion: Multiple therapeutic targets have been identified and several have shown efficacy. Work is needed to define appropriate trial outcome measures. Collaboration between government agencies, patient advocacy groups, and investigator-led consortia is critical for completing new clinical trials which should pave the way for new therapies in clinical practice.

Medical and dietary management of eosinophilic esophagitis

OBJECTIVE

Eosinophilic esophagitis (EoE) is a disease of chronic, allergen-driven, T-helper 2 (Th2) immune-mediated inflammation that progresses to fibrostenosis of the esophagus if left untreated. There are currently no Food and Drug Administration (FDA)-approved drugs for the treatment of EoE. This review focuses on the medical and dietary management of EoE.

DATA SOURCES

Manuscripts on EoE treatments were identified on PubMed.

STUDY SELECTIONS

Original research, randomized control trials, retrospective studies, meta-analyses, case series, and on occasions, case reports of high relevance, were selected and reviewed.

RESULTS

Current treatment strategies available to EoE patients center on monotherapy or combination therapy with dietary modification to exclude antigenic stimulation and topical corticosteroids to control Th2-mediated tissue inflammation and pathologic remodeling. Dilation as a rescue therapy for the narrowed, fibrostenotic, symptomatic esophagus can potentially be avoided with optimal medical and elimination diet therapies. The molecular mechanisms underlying EoE pathogenesis are being unraveled, from which targeted therapies can be developed and evaluated in preclinical and clinical studies. Current clinical research efforts focus on optimization of topical corticosteroid delivery, dosing, frequency, and duration of treatment, either alone or in combination with tailored elimination diet. Preliminary clinical trials with biologics targeting interleukin (IL)-5 and IL-13/IL-4 have been completed.

CONCLUSION

Topical corticosteroid, elimination diet, and dilation are the current treatment modalities for confirmed EoE. The use of proton-pump inhibitors (PPI) is being suggested as a potential regimen to treat EoE, based on evolving understanding of PPI-responsive esophageal eosinophilia (PPI-REE). The complexity of EoE treatment regimens and frequent follow-ups require a multimodal, multi-disciplinary management approach to optimize patient care.

Targeting the Interleukin-5 Pathway for Treatment of Eosinophilic Conditions Other than Asthma

Improved understanding of the contribution of eosinophils to various chronic inflammatory conditions, most notably allergic asthma, has encouraged development of monoclonal antibodies specifically targeting mediators and surface receptors involved in eosinophil expansion and activation. The pivotal role of interleukin-5 (IL-5) in eosinophil biology, its high specificity for this leukocyte subset, and its involvement in the majority of eosinophilic conditions make it a very enticing target for treatment of eosinophil-mediated disorders. Two types of antibodies have been developed to target eosinophils: antibodies against IL-5 (mepolizumab and reslizumab), and an antibody against the IL-5-receptor-alpha-chain (IL-5Rα) (benralizumab). Both types of antibodies prevent IL-5 from engaging its receptor and in addition, anti-IL-5Rα antibodies induce target-cell lysis. They have been shown to reduce circulating eosinophil counts rapidly in humans with various disorders. Herein, a brief overview of the role of IL-5 in eosinophil biology will be presented, followed by a description of the development and characteristics of antibodies targeting IL-5 or its receptor. Results of clinical trials evaluating the efficacy and safety of these new antibodies in diseases (other than eosinophilic asthma) with prominent tissue eosinophilia are reviewed, followed by safety considerations and potential future applications.

Advances in Biomarker-Guided Therapy for Pediatric- and Adult-Onset Neuroinflammatory Disorders: Targeting Chemokines/Cytokines

The concept and recognized components of “neuroinflammation” are expanding at the intersection of neurobiology and immunobiology. Chemokines (CKs), no longer merely necessary for immune cell trafficking and positioning, have multiple physiologic, developmental, and modulatory functionalities in the central nervous system (CNS) through neuron–glia interactions and other mechanisms affecting neurotransmission. They issue the “help me” cry of neurons and astrocytes in response to CNS injury, engaging invading lymphoid cells (T cells and B cells) and myeloid cells (dendritic cells, monocytes, and neutrophils) (adaptive immunity), as well as microglia and macrophages (innate immunity), in a cascade of events, some beneficial (reparative), others destructive (excitotoxic). Human cerebrospinal fluid (CSF) studies have been instrumental in revealing soluble immunobiomarkers involved in immune dysregulation, their dichotomous effects, and the cells—often subtype specific—that produce them. CKs/cytokines continue to be attractive targets for the pharmaceutical industry with varying therapeutic success. This review summarizes the developing armamentarium, complexities of not compromising surveillance/physiologic functions, and insights on applicable strategies for neuroinflammatory disorders. The main approach has been using a designer monoclonal antibody to bind directly to the chemo/cytokine. Another approach is soluble receptors to bind the chemo/cytokine molecule (receptor ligand). Recombinant fusion proteins combine a key component of the receptor with IgG1. An additional approach is small molecule antagonists (protein therapeutics, binding proteins, and protein antagonists). CK neutralizing molecules (“neutraligands”) that are not receptor antagonists, high-affinity neuroligands (“decoy molecules”), as well as neutralizing “nanobodies” (single-domain camelid antibody fragment) are being developed. Simultaneous, more precise targeting of more than one cytokine is possible using bispecific agents (fusion antibodies). It is also possible to inhibit part of a signaling cascade to spare protective cytokine effects. “Fusokines” (fusion of two cytokines or a cytokine and CK) allow greater synergistic bioactivity than individual cytokines. Another promising approach is experimental targeting of the NLRP3 inflammasome, amply expressed in the CNS and a key contributor to neuroinflammation. Serendipitous discovery is not to be discounted. Filling in knowledge gaps between pediatric- and adult-onset neuroinflammation by systematic collection of CSF data on CKs/cytokines in temporal and clinical contexts and incorporating immunobiomarkers in clinical trials is a challenge hereby set forth for clinicians and researchers.