Tezepelumab, an anti-thymic stromal lymphopoietin monoclonal antibody, in the treatment of moderate to severe atopic dermatitis: A randomized phase 2a clinical trial

A chalcone derivative suppresses TSLP induction in mice and human keratinocytes through binding to BET family proteins

Although treatments for allergic diseases have improved, side effects and treatment resistance remain as challenges. New therapeutic drugs for allergic diseases are urgently required. Thymic stromal lymphopoietin (TSLP) is a cytokine target for prevention and treatment of allergic diseases. Since TSLP is produced from epithelial cells in allergic diseases, TSLP inhibitors may be new anti-allergic drugs. We previously identified a new inhibitor of TSLP production, named 16D10. However, its target of action remained unclarified. In this study, we found proteins binding to 16D10 from 24,000 human protein arrays by AlphaScreen-based high-throughput screening and identified bromodomain and extra-terminal (BET) family proteins as targets. We also clarified the detailed mode of interaction between 16D10 and a BET family protein using X-ray crystallography. Furthermore, we confirmed that inhibitors of BET family proteins suppressed TSLP induction and IL-33 and IL-36γ expression in both mouse and human keratinocyte cell lines. Taken together, our findings suggest that BET family proteins are involved in the suppression of TSLP production by 16D10. These proteins can contribute to the pathology of atopic dermatitis via TSLP regulation in keratinocytes and have potential as therapeutic targets in allergic diseases.

Strategies for choosing a biologic for your patient with allergy or asthma

OBJECTIVE

To summarize the therapeutic effects and safety of biologics either approved or in clinical development for asthma, chronic obstructive pulmonary disease, urticaria, nasal polyps, atopic dermatitis, and eosinophilic esophagitis. This review attempts to provide some guidance when choosing among agents.

DATA SOURCES

Recently published articles obtained through PubMed database searches including research articles, review articles, and case reports.

STUDY SELECTIONS

PubMed database searches were conducted using the following keywords: biologics, asthma, COPD, urticaria, atopic dermatitis, food allergy, nasal polyps, and eosinophilic esophagitis.

RESULTS

The approval of omalizumab by the Food and Drug Administration in 2003 for patients with asthma paved the way for the development of multiple biologics for a variety of respiratory and allergic diseases. Agents approved by the Food and Drug Administration include mepolizumab, reslizumab, benralizumab, and dupilumab, and several more are in the late stages of clinical development. Owing to the overlap in the pathogenesis of respiratory and allergic diseases, many of these biologics target multiple respiratory and allergic diseases simultaneously.

CONCLUSION

The numerous biologic options have made the selection of the best biologic for each patient a potential conundrum for clinicians. Adequate point of care biomarkers to facilitate personalized medical therapy are generally lacking. Furthermore, although clinically effective and generally safe, none of the biologics discussed in this review have induced long-standing disease remission. Nevertheless, these agents have given us the opportunity to treat the most severe patients and to better understand the biology of respiratory and allergic diseases. As knowledgeable physicians, we should embrace and be educated on these novel therapies and the pathways they target.

Effects of systemic therapies on pruritus in adults with atopic dermatitis: a systematic review and meta-analysis

Pruritus is a hallmark of atopic dermatitis (AD), affecting disease severity and patients' quality of life. In AD uncontrolled with first-line topical therapies or in moderate-to-severe AD, systemic therapies are used, however, there are paucity of head-to-head trials comparing their effectiveness. The aim was to compare the effectiveness between the systemic therapies on relieving pruritus in moderate-to-severe AD in adults through meta-analysis. PubMed, EMBASE, Medline and CINAHL databases were searched from inception up to 31 May 2020 for placebo-controlled randomised controlled trials investigating the effectiveness of systemic therapies on pruritus with moderate-to-severe AD in adults aged ≥ 16. 26 studies were identified (n = 5,190 participants). There was a large reduction in pruritus compared to placebo (standard mean difference [95% confidence interval]) with dupilumab every 2 weeks (q2w) (-0.88 [-1.13, -0.63]), q2w + topical corticosteroids (-0.77 [-0.91, -0.62]); dupilumab once weekly (qw) (-0.99 [-1.29, -0.68]), qw + topical corticosteroids (-0.70 [-0.81, -0.59]); a large reduction with ciclosporin (-1.30 [-2.34, -0.26]); a small reduction with mepolizumab (-0.27 [-0.89, 0.35]), interferon gamma (-0.31 [-0.75, 0.12]); a large reduction with azathioprine (-0.85 [-2.07, 0.35]). Amongst investigational drugs, nemolizumab 2.0mg/kg was the most effective (-8.13 [-9.31, -6.94]). The majority of systemic therapies were superior to placebo in reducing pruritus. In particular, dupilumab studies consistently showed large improvements in pruritus and nemolizumab showed the strongest anti-pruritic effects, however future head-to-head trials are required for conclusive evidence.

The New Era of Biologics in Atopic Dermatitis: A Review

Atopic dermatitis (AD) is a prevalent inflammatory skin disorder affecting all age and ethnic groups. The age-dependent varying appearance and extent of pruritic lesions are accompanied by distinct individual suffering, highlighting the importance of effective treatment options. Over the past years systemic drugs have considerably extended therapeutic approaches of patients with moderate to severe AD, in particular new biologics, most notably dupilumab has appeared as major breakthrough. In addition to monoclonal blockade of IL-4 and IL-13 pathway, more cytokines have been found to play a substantial role in AD pathogenesis, presenting potential targets for new therapy options.

From Emollients to Biologicals: Targeting Atopic Dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease and significantly impacts patients' lives, particularly in its severe forms. AD clinical presentation varies over the course of the disease, throughout different age groups, and across ethnicities. AD is characterized by a spectrum of clinical phenotypes as well as endotypes. Starting from the current description of AD pathogenesis, this review explores the rationale of approved AD therapies from emollients to biologicals and introduces novel promising drugs.

Pilot Study of Anti-Th2 Immunotherapy for the Treatment of Breast Cancer-Related Upper Extremity Lymphedema

Recent studies suggest that Th2 cells play a key role in the pathology of secondary lymphedema by elaborating cytokines such as IL4 and IL13. The aim of this study was to test the efficacy of QBX258, a monoclonal IL4/IL13 neutralizing antibody, in women with breast cancer-related lymphedema (BCRL). We enrolled nine women with unilateral stage I/II BCRL and treated them once monthly with intravenous infusions of QBX258 for 4 months. We measured limb volumes, bioimpedance, and skin tonometry, and analyzed the quality of life (QOL) using a validated lymphedema questionnaire (Upper Limb Lymphedema 27, ULL-27) before treatment, immediately after treatment, and 4 months following treatment withdrawal. We also obtained 5 mm skin biopsies from the normal and lymphedematous limbs before and after treatment. Treatment was well-tolerated; however, one patient with a history of cellulitis developed cellulitis during the trial and was excluded from further analysis. We found no differences in limb volumes or bioimpedance measurements after drug treatment. However, QBX258 treatment improved skin stiffness (p < 0.001) and improved QOL measurements (Physical p < 0.05, Social p = 0.01). These improvements returned to baseline after treatment withdrawal. Histologically, treatment decreased epidermal thickness, the number of proliferating keratinocytes, type III collagen deposition, infiltration of mast cells, and the expression of Th2-inducing cytokines in the lymphedematous skin. Our limited study suggests that immunotherapy against Th2 cytokines may improve skin changes and QOL of women with BCRL. This treatment appears to be less effective for decreasing limb volumes; however, additional studies are needed.

A new era has begun: Treatment of atopic dermatitis with biologics

The era of biologics for the treatment of moderate-to-severe atopic dermatitis (AD) began in 2017 with the approval of dupilumab, a monoclonal antibody that binds to the α-subunit of the interleukin IL-4 receptor. Until then, only conventional immunosuppressants were available for systemic treatment, of which only cyclosporine is approved for the treatment of severe AD. In the meantime, the therapeutic landscape of AD has been changing rapidly, and additional biologics have been developed which target IL-13, the IL-31 receptor, OX40, and OX40L, among others. Many of these substances have already shown promising results in phase 1, 2, and in some cases also phase 3 trials. In June 2021, tralokinumab, an IL-13 antibody, has been approved in Europe for the treatment of moderate-to-severe AD in adults. In addition to antibody-based therapies, “small molecules” that, e.g., inhibit Janus kinases enrich the armamentarium of systemic AD therapies. With all these agents, not only will many more targeted therapies become available, but also will the complex and heterogeneous pathophysiological processes of this disease be better understood.

Short-Term Effectiveness and Safety of Biologics and Small Molecule Drugs for Moderate to Severe Atopic Dermatitis: A Systematic Review and Network Meta-Analysis

Background: Some Network Meta-analysis (NMA) has been published regarding atopic dermatitis (AD). These studies have considered drugs under investigation both in monotheraphy or in combination with topical corticosteroids, as well as systemic immunosuppressant therapies. The objective of this study is to evaluate the efficacy and safety of biological agents and small molecules in AD. Methods: A systematic review and NMA of biologics agents and small molecules in AD was performed. A literature search was performed using MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for clinical trials and systematic reviews between January 2000 and 19 December 2020. Only randomized clinical trials (RCTs) were included. It was limited to English language and adult human subjects. Two networks were evaluated: monotherapy and combination with TCS. The two primary outcomes were Eczema Area and Severity Index (EASI) 75 and EASI 90 change from baseline to week 12–16, depending on source study cut-off. The Cochrane’s Risk of Bias tool 2011 update was used to analyze the risk of bias, focused on the primary objectives. Results: 30 RCTs (included in 26 publications) were included in the systematic review. Finally, 23 RCTs were included in the quantitative analysis (14 RCTs including 3582 patients in monotherapy; and 9 RCTs including 3686 patients with TCS). In monotherapy, a higher percentage of patients achieving EASI-75 was obtained with Upadacitinib 30 mg [OR: 18.90 (13.94; 25.62)] followed by Abrocitinib 200 mg [OR = 11.26 (7.02; 18.05)] and Upadacitinib 15 mg [OR: 10.89 (8.13; 14.59)]. These results were also observed in studies where the use of topical corticosteroid (TCS) was allowed (OR Upadacitinib 30 mg = 9.43; OR Abrocitinib 200 mg = 6.12; OR Upadacitinib 15 mg = 5.20). Regarding IGA, the percentage of patients achieving IGA0/1 was higher with both doses of Upadacitinib 30 mg [OR: 19.13 (13.14; 27.85)] and 15 mg [OR = 10.95 (7.52; 15.94). In studies where the use of TCS were allowed, however, the dose of Abrocitinib 200 mg [OR = 6.10 (3.94; 9.44)] showed higher efficacy than Upadacitinib 15 mg [OR = 5.47 (3.57; 8.41)]. Regarding safety, the drugs with the highest probability of presenting adverse effects were the Janus kinases (JAK) inhibitors, Upadacitinib and Abrocitinib in monotherapy and Baricitinib in combination with TCS. Discussion: Some risks of bias have been found, which must be taken into account when interpreting the results. The funnel plot shows a possible publication bias that may underestimate the efficacy of drugs. Upadacitinib and Abrocitinib are the drugs with the highest efficacy, both in monotherapy and in association with TCS. However, they were also those associated with the highest risk of adverse effects, showing monoclonal antibodies better safety profile. Limitations: We have included molecules still in the development phase as well studies completed and presented at conferences and with data available in Trialsgov^® but not published yet. Several molecules’ development had included a small number of patients from 12 to 17 years of age, without being able to differentiate the results from the adult population. Other: Founding: None. PROSPERO database registration number CRD42021225793.

Thymic stromal lymphopoietin, skin barrier dysfunction, and the atopic march

OBJECTIVE

Atopic dermatitis often precedes the development of other atopic diseases, and the atopic march describes this temporal relationship in the natural history of these diseases. Although the pathophysiological mechanisms that underlie this relationship are poorly understood, epidemiologic and genetic data have suggested that the skin might be an important route of sensitization to allergens.

DATA SOURCES

Review of recent studies on the role of skin barrier defects in systemic allergen sensitization.

STUDY SELECTIONS

Recent publications on the relationship between skin barrier defects and expression of epithelial cell-derived cytokines.

RESULTS

Animal models have begun to elucidate on how skin barrier defects can lead to systemic allergen sensitization. Emerging data now suggest that epithelial cell-derived cytokines, such as thymic stromal lymphopoietin, drive the progression from atopic dermatitis to asthma and food allergy. Skin barrier defects can lead to induction of epithelial cell-derived cytokines, which in turn leads to the initiation and maintenance of allergic inflammation and the atopic march.

CONCLUSION

Development of new biologic drug targeting type 2 cytokines provides novel therapeutic interventions for atopic dermatitis.

Basophils promote barrier dysfunction and resolution in the atopic skin

BACKGROUND

The type 2 cytokines IL-4 and IL-13 promote not only atopic dermatitis (AD) but also the resolution of inflammation. How type 2 cytokines participate in the resolution of AD is poorly known.

OBJECTIVE

Our aim was to determine the mechanisms and cell types governing skin inflammation, barrier dysfunction, and resolution of inflammation in a model of AD.

METHODS

Mice that exhibit expression of IL-4, IL-13, and MCPT8 or that could be depleted of basophils or eosinophils, be deficient in IL-4 or MHC class II molecules, or have basophils lacking macrophage colony-stimulating factor (M-CSF) were treated with calcipotriol (MC903) as an acute model of AD. Kinetics of the disease; keratinocyte differentiation; and leukocyte accumulation, phenotype, function, and cytokine production were measured by transepidermal water loss, histopathology, molecular biology, or unbiased analysis of spectral flow cytometry.

RESULTS

In this model of AD, basophils were activated systemically and were the initial and main source of IL-4 in the skin. Basophils and IL-4 promoted epidermal hyperplasia and skin barrier dysfunction by acting on keratinocyte differentiation during inflammation. Basophils, IL-4, and basophil-derived M-CSF inhibited the accumulation of proinflammatory cells in the skin while promoting the expansion and function of proresolution M2-like macrophages and the expression of probarrier genes. Basophils kept their proresolution properties during AD resolution.

CONCLUSION

Basophils can display both beneficial and detrimental type 2 functions simultaneously during atopic inflammation.

Chronic itch: emerging treatments following new research concepts

Until recently, itch pathophysiology was poorly understood and treatments were poorly effective in relieving itch. Current progress in our knowledge of the itch processing, the numerous mediators and receptors involved has led to a large variety of possible therapeutic pathways. Currently, inhibitors of IL-31, IL-4/13, NK₁ receptors, opioids and cannabinoids, JAK, PDE4 or TRP are the main compounds involved in clinical trials. However, many new targets, such as Mas-related GPCRs and unexpected new pathways need to be also explored.

Atopic dermatitis: an expanding therapeutic pipeline for a complex disease

Atopic dermatitis (AD) is a common chronic inflammatory skin disease with a complex pathophysiology that underlies a wide spectrum of clinical phenotypes. AD remains challenging to treat owing to the limited response to available therapies. However, recent advances in understanding of disease mechanisms have led to the discovery of novel potential therapeutic targets and drug candidates. In addition to regulatory approval for the IL-4Ra inhibitor dupilumab, the anti-IL-13 inhibitor tralokinumab and the JAK1/2 inhibitor baricitinib in Europe, there are now more than 70 new compounds in development. This Review assesses the various strategies and novel agents currently being investigated for AD and highlights the potential for a precision medicine approach to enable prevention and more effective long-term control of this complex disease.

Recent advances in understanding of the complex phenotype and mechanisms underlying atopic dermatitis (AD) have revealed multiple new potential targets for pharmacological intervention. Here, Bieber reviews therapeutic strategies and assesses the expanding pipeline for the therapy of AD, highlighting the potential for a precision medicine approach to the management of this complex disorder.

Novel pathogenesis of atopic dermatitis from the view of cytokines in mice and humans

Type 2 immunity and inflammation underlie allergic skin disorders, such as atopic dermatitis (AD). In type 2 inflammation, IL-4, IL-13, and IL-5, which are signature type 2 cytokines, are mainly produced by type 2 helper T (Th2) cells and form the characteristic features of AD. Epithelial cell-derived cytokines such as IL-25, IL-33, and TSLP initiate type 2 inflammation by modulating various cells, including group 2 innate lymphoid cells. Moreover, IL-31, a newly identified type 2 cytokine produced mainly by Th2 cells, induces pruritus by acting on sensory neurons in the skin. Based on both basic and clinical findings, several biologics targeting Th2 cytokines have been developed and exhibited significant efficacy as therapeutic reagents for AD. We have summarized the roles of each cytokine (IL-4, 5, 13, 25, 31, and 33, and TSLP) in the development of type 2 inflammation, especially AD, from the view of basic studies in mice and clinical trials/observation in humans.

Update on the Pathogenesis and Therapy of Atopic Dermatitis

Atopic dermatitis (AD) is a common inflammatory skin disorder characterized by recurrent eczematous lesions and intense itch. Although it most often starts in infancy and affects children, it is also highly prevalent in adults. In this article, the main aspects of AD have been updated, with a focus on the pathogenetic and therapeutic aspects. The pathogenesis of AD is complex, and it is evident that a strong genetic predisposition, epidermal dysfunction, skin microbiome abnormalities, immune dysregulation, and the neuroimmune system are critical in AD development. Mutations in the genes associated with disrupted epidermal barrier, exaggerated pathological inflammation and inadequate antimicrobial peptides can promote enhanced Th2 inflammation and mediate pruritus. Current understanding of etiology highlights gut microbial diversity, NK cell deficiency, and different immunological phenotype with age and race. For topical anti-inflammatory treatment for mild-to-severe AD, phosphodiesterase 4 inhibitors (PDE-4), JAK inhibitors, and microbiome transplantation with Roseomonas mucosa provided more management selections. The treatment of moderate-to-severe AD has been limited to merely symptomatic and relatively nonspecific immunosuppressive approaches. In-depth understanding of the pathogenesis of AD has led to the development of innovative and targeted therapies, such as biologic agents targeting interleukin (IL)-4, IL-13 and JAK/STAT inhibitors. Other potential therapeutic agents for AD include agents targeting the T helper (Th) 22 and Th17/IL23 pathway. Antipruritic therapy and complementary probiotics therapy have also been reviewed.

Definition of treatment goals in terms of clinician-reported disease severity and patient-reported outcomes in moderate-to-severe adult atopic dermatitis: a systematic review

BACKGROUND

Atopic dermatitis (AD) is a chronically relapsing skin disease. Although a definitive cure is not available, appropriate treatment can control the disease. The advent of biologic drugs has led to the need for a clear definition of the disease severity and treatment response. A standardized list of outcomes that defines clinician-reported disease severity and patients' reported severity are therefore essential. Solid criteria to define the response to treatment and treatment failure are lacking to date.

OBJECTIVE

This systematic review defines treatment goals in terms of clinician-reported disease severity and patient-reported outcomes, referring to the published moderate-to-severe AD clinical trials. The application of these goals in daily clinical practice will ensure a better selection of available treatment options, thus increasing patient quality of care.

MATERIALS AND METHODS

A systematic literature search was performed to identify the treatments goals of randomized controlled clinical trials (RCTs) on moderate-to-severe adult AD published between January 2000 and October 2020.

RESULTS

In total, 14 studies met the eligibility criteria. The most widely used tools in terms of clinician-reported disease severity were the Scoring of Atopic Dermatitis (SCORAD) followed by the Eczema Area Severity Score (EASI) and Investigator Global Assessment (IGA). For disease severity scales as efficacy outcome in RCTs, the greatest standardization and reproducibility was for improvement of at least 50% in EASI score and IGA score reduction of ≥2 grades from baseline. The most widely used tools from the patients' perspective were the Dermatology Life Quality Index (DLQI), Numeric Rate Scale (NRS)-itch and Patient Oriented Eczema Measure Score (POEM). In terms of patients' reported efficacy outcomes in RCTs, a numerical DLQI, NRS-itch and POEM score improvement of at least 4 points from baseline was reported.

CONCLUSIONS

This systematic review highlights the need for collaboration between experts in order to define and optimize treatment outcomes. Despite considerable progress in harmonizing outcome measures, promoted by the foundation of the Harmonizing Outcome Measures for Eczema (HOME) initiative in 2008, our results demonstrate that this endpoint is still an unmet need. Based on the literature data we propose a minimum treatment goal algorithm for use in daily clinical practice aimed at stimulating a discussion on how the care of AD patients could be further improved.

Multifaceted MRGPRX2: New insight into the role of mast cells in health and disease

Cutaneous mast cells (MCs) express Mas-related G protein-coupled receptor-X2 (MRGPRX2; mouse ortholog MrgprB2), which is activated by an ever-increasing number of cationic ligands. Antimicrobial host defense peptides (HDPs) generated by keratinocytes contribute to host defense likely by 2 mechanisms, one involving direct killing of microbes and the other via MC activation through MRGPRX2. However, its inappropriate activation may cause pseudoallergy and likely contribute to the pathogenesis of rosacea, atopic dermatitis, allergic contact dermatitis, urticaria, and mastocytosis. Gain- and loss-of-function missense single nucleotide polymorphisms in MRGPRX2 have been identified. The ability of certain ligands to serve as balanced or G protein-biased agonists has been defined. Small-molecule HDP mimetics that display both direct antimicrobial activity and activate MCs via MRGPRX2 have been developed. In addition, antibodies and reagents that modulate MRGPRX2 expression and signaling have been generated. In this article, we provide a comprehensive update on MrgprB2 and MRGPRX2 biology. We propose that harnessing MRGPRX2's host defense function by small-molecule HDP mimetics may provide a novel approach for the treatment of antibiotic-resistant cutaneous infections. In contrast, MRGPRX2-specific antibodies and inhibitors could be used for the modulation of allergic and inflammatory diseases that are mediated via this receptor.

Gut Microbiota, Probiotics, and Their Interactions in Prevention and Treatment of Atopic Dermatitis: A Review

Atopic dermatitis (AD) is a public health concern and is increasing in prevalence in urban areas. Recent advances in sequencing technology have demonstrated that the development of AD not only associate with the skin microbiome but gut microbiota. Gut microbiota plays an important role in allergic diseases including AD. The hypothesis of the “gut-skin” axis has been proposed and the cross-talk mechanism between them has been gradually demonstrated in the research. Probiotics contribute to the improvement of the intestinal environment, the balance of immune responses, regulation of metabolic activity. Most studies suggest that probiotic supplements may be an alternative for the prevention and treatment of AD. This study aimed to discuss the effects of probiotics on the clinical manifestation of AD based on gut microbial alterations. Here we reviewed the gut microbial alteration in patients with AD, the association between gut microbiota, epidermal barrier, and toll-like receptors, and the interaction of probiotics and gut microbiota. The potential mechanisms of probiotics on alleviating AD via upregulation of epidermal barrier and regulation of immune signaling had been discussed, and their possible effective substances on AD had been explored. This provides the supports for targeting gut microbiota to attenuate AD.

The Implications of Pruritogens in the Pathogenesis of Atopic Dermatitis

Atopic dermatitis (AD) is a prototypic inflammatory disease that presents with intense itching. The pathophysiology of AD is multifactorial, involving environmental factors, genetic susceptibility, skin barrier function, and immune responses. A recent understanding of pruritus transmission provides more information about the role of pruritogens in the pathogenesis of AD. There is evidence that pruritogens are not only responsible for eliciting pruritus, but also interact with immune cells and act as inflammatory mediators, which exacerbate the severity of AD. In this review, we discuss the interaction between pruritogens and inflammatory molecules and summarize the targeted therapies for AD.

Novel Targeted Biological Agents for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a common inflammatory dermatologic disease clinically characterized by intense itch, recurrent eczematous lesions, and a chronic or relapsing disease course. Mild-to-moderate AD can be controlled by using moisturizers and topical immunomodulators such as topical corticosteroids and calcineurin inhibitors. If topical therapies fail, phototherapy and systemic immunosuppressant therapies, such as ciclosporin, methotrexate, and azathioprine, can be considered. However, relapse and side effects could still occur. The pathogenesis of AD involves epidermal barrier dysfunction, skin microbiome abnormalities, and cutaneous inflammation. Inflammatory mediators, such as interleukin (IL)-4, IL-13, IL-31, IL-33, IL-17, IL-23, and thymic stromal lymphopoietin, are involved in AD development. Therefore, a series of biological agents targeting these cytokines are promising approaches for treating AD. Dupilumab is the first biological agent approved for the treatment of AD in patients aged 6 years and older in the United States. Tralokinumab, lebrikizumab, and nemolizumab have also been confirmed to have significant efficacy against AD in phase III or IIb clinical trials. Also, fezakinumab was effective in severe AD patients in a phase IIa trial. However, phase II trials of ustekinumab, tezepelumab, etokimab, secukinumab, and omalizumab have failed to meet their primary endpoints. Phase II trials of GBR 830 and KHK 4083 are ongoing. In general, further studies are needed to explore new therapeutic targets and improve the efficacy of biological agents.

Thymic Stromal Lymphopoietin in Cutaneous Immune-Mediated Diseases

Thymic stromal lymphopoietin (TSLP) was initially demonstrated to be critical in regulating inflammatory responses among various allergic disorders (such as atopic dermatitis, food allergy, and asthma). Although two isoforms (short form and long form) of TSLP have been demonstrated in human tissues, the long form of TSLP (lfTSLP) is strongly implicated in the pathogenesis of allergies and cutaneous immune-mediated diseases. The immunomodulatory activity of lfTSLP varies widely, driving T helper (Th) cells polarizing Th2 and Th17 immune responses and inducing itch. Moreover, lfTSLP is closely associated with skin fibrosis, epidermal hyperplasia, angiogenesis, and homeostatic tolerogenic regulations. This review highlights significant progress from experimental and clinical studies on lfTSLP in cutaneous immune-mediated diseases (atopic dermatitis, psoriasis, bullous pemphigoid, systemic sclerosis, chronic spontaneous urticaria, Behçet's disease, vitiligo, rosacea, systemic lupus erythematosus, and alopecia areata). We also offer original insights into the pleiotropic properties of the cytokine TSLP in various pathophysiological conditions, with significant clinical implications of TSLP-targeted therapies for immune-mediated skin diseases in the future.

Overview of severe asthma, with emphasis on pediatric patients: a review for practitioners

Asthma is the most common life-threatening chronic disease in children. Although guidelines exist for the diagnosis and treatment of asthma, treatment of severe, pediatric asthma remains difficult. Limited studies in the pediatric population on new asthma therapies, complex issues with adolescence and adherence, health disparities, and unequal access to guideline-based care complicate the care of children with severe, persistent asthma. The purpose of this review is to provide an overview of asthma, including asthma subtypes, comorbidities, and risk factors, to discuss diagnostic considerations and pitfalls and existing treatments, and then present existing and emerging therapeutic approaches to asthma management. An improved understanding of asthma heterogeneity, clinical characteristics, inflammatory patterns, and pathobiology can help further guide the management of severe asthma in children. More studies are needed in the pediatric population to understand emerging therapeutics application in children. Effective multimodal strategies tailored to individual characteristics and a commitment to address risk factors, modifiers, and health disparities may help reduce the burden of asthma in the USA.

Current Insights into Immunology and Novel Therapeutics of Atopic Dermatitis

Atopic dermatitis (AD) is one of the most prevalent inflammatory disease among non-fatal skin diseases, affecting up to one fifth of the population in developed countries. AD is characterized by recurrent pruritic and localized eczema with seasonal fluctuations. AD initializes the phenomenon of atopic march, during which infant AD patients are predisposed to progressive secondary allergies such as allergic rhinitis, asthma, and food allergies. The pathophysiology of AD is complex; onset of the disease is caused by several factors, including strong genetic predisposition, disrupted epidermal barrier, and immune dysregulation. AD was initially characterized by defects in the innate immune system and a vigorous skewed adaptive Th2 response to environmental agents; there are compelling evidences that the disorder involves multiple immune pathways. Symptomatic palliative treatment is the only strategy to manage the disease and restore skin integrity. Researchers are trying to more precisely define the contribution of different AD genotypes and elucidate the role of various immune axes. In this review, we have summarized the current knowledge about the roles of innate and adaptive immune responsive cells in AD. In addition, current and novel treatment strategies for the management of AD are comprehensively described, including some ongoing clinical trials and promising therapeutic agents. This information will provide an asset towards identifying personalized targets for better therapeutic outcomes.

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.

Biologicals for the prevention of anaphylaxis

PURPOSE OF REVIEW

To review the use of biological agents (BA) in the treatment of anaphylaxis in the view of the new knowledge in the field to support the quality of care and prevention.

RECENT FINDINGS

Some BA, as a single medication or as combined therapy to food or venom immunotherapy, are effectively able to reduce most of the severe anaphylactic reactions.

SUMMARY

Anaphylaxis is a recognized clinical emergency, which requires prompt identification and treatment. Several biologic therapies and new devices are emerging as a potential preventive treatment for anaphylaxis. However, adrenaline (epinephrine) is still the first-line treatment for any type of anaphylaxis. Biological drugs, such as omalizumab, whereas not US Food and Drug Administration (FDA) nor European Medicines Agency (EMA) approved for anaphylaxis, have been used as therapeutic adjuvants in the preventive treatment of anaphylaxis, but cost-effectiveness should be considered individually.

New Biologics for the Treatment of Atopic Dermatitis: Analysis of Efficacy, Safety, and Paradoxical Atopic Dermatitis Acceleration

Atopic dermatitis (AD) is a chronic, inflammatory skin disease with an eczematous rash and itching. Due to undesired adverse effects of traditional systemic treatment, there is still an unmet need for safe and effective long-term therapy for refractory AD. As our understanding of the pathogenesis underlying AD grows, novel treatments targeting specific molecules have been developed. Here, we discuss the efficacy and safety profiles of these drugs in recent clinical trials. Among their adverse effects, of particular note is AD acceleration. Although there is still debate about whether certain adverse reactions can be said to be paradoxical adverse events (PAEs), a wide range of PAEs have been reported during biological treatment for chronic immune-mediated diseases. Close surveillance of novel biologics is crucial to detect new undescribed paradoxical reactions and to shed light on the convoluted pathogenesis of AD.

Emerging Systemic Therapeutic Biologics and Small Molecules for Atopic Dermatitis: How to Decide Which Treatment Is Right for Your Patients

The evolving discoveries in atopic dermatitis (AD) broaden our understanding of the pathogenesis of the disease and, above all, enable better management for patients. Dupilumab was the first biologic for AD, and since its approval, many new treatments have emerged in both late- and early-stage clinical trials. These trials have led to a further understanding of the pathogenesis of AD and to the identification of additional potential therapeutic targets. This review will highlight the emerging therapies and provide approaches on how to choose the right treatment for your patients.

Biologics for Treatment of Atopic Dermatitis: Current Status and Future Prospect

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by intense pruritus and recurrent eczematous lesions that significantly impair quality of life. It is a heterogeneous disease affecting both children and adults. The treatment of moderate-to-severe forms of AD is challenging, as topical corticosteroids are often insufficient to achieve disease control or inappropriate and off-label use of immunosuppressants may have significant undesirable side effects. The development of targeted biologic therapies specifically for AD is thus highly desirable. Dupilumab is the only biologic therapy that is Food and Drug Administration approved for the treatment of moderate-to-severe AD in patients 6 years and older, with consistent long-term efficacy and safety trial data. In this article, we review the mechanisms, safety, and efficacy of dupilumab from recent clinical trials, and we review the current data, mechanism of action, clinical efficacy, and limitations of new biologics currently in phase 2 and 3 clinical trials (lebrikizumab, tralokinumab, nemolizumab, tezepelumab, and ISB 830).

Experimental Drugs with the Potential to Treat Atopic Eczema

INTRODUCTION

Eczema or atopic dermatitis (AD) is a chronically relapsing dermatosis characterized by pruritus and a significant impact on the quality of life.

METHODS

The authors undertook a structured search of peer-reviewed research articles from PubMed and Google Scholar. Recent and up-to-date studies relevant to the topic were included.

RESULTS

This report overviews current treatment and experimental drug for AD. Topical agents including topical phosphodiesterase E4 (PDE4) inhibitors such as crisaborole are efficacious in the treatment of AD with few side effects. Monoclonal antibodies such as dupilumab given subcutaneously are efficacious for more severe disease. Systemic treatment can ameliorate symptoms in severe and recalcitrant AD. New systemic treatment includes several traditional herbal formulations that have undergone clinical trials using modern research methodology to determine their efficacy and safety. AD is associated with many complicating psychosocial issues. Often suboptimal efficacy is due to unrealistic expectations and poor compliance making treatment difficult in spite of effective treatment and efforts in drug discovery. Randomized trials have shown that novel topical and subcutaneous medications are safe and efficacious. Regarding herbs, a methodology for the investigation of herbal medications is often flawed and scientific evidence is lacking. Experimental drugs include various biologics, PDE4 and JAK inhibitors in topical, oral, subcutaneous or intravenous forms are in various phases of trials.

CONCLUSION

Many novel medications demonstrate efficacy for AD. Experimental drugs include various biologics, PDE4 and JAK inhibitors are in various phases of trials.

Itch in Atopic Dermatitis - What Is New?

Atopic dermatitis (AD) is among the most frequent inflammatory skin diseases in humans, affecting up to 20% of children and 10% of adults in higher income countries. Chronic pruritus is a disease-defining symptom of AD, representing the most burdensome symptom for patients. Severe chronic pruritus causes significant sleep disturbances and impaired quality of life, as well as increased anxiety, depression and suicidal behavior. Until recently, skin care, topical corticosteroids, and calcineurin-inhibitors were primarily used to treat mild to moderate AD, while phototherapy and immunosuppressive agents such as corticosteroids, cyclosporine, and methotrexate were used to treat patients with moderate to severe AD. The potential short- and long-term adverse events associated with these treatments or their insufficient therapeutic efficacy limited their use in controlling pruritus and eczema in AD patients over longer periods of time. As our understanding of AD pathophysiology has improved and new systemic and topical treatments have appeared on the market, targeting specific cytokines, receptors, or their intracellular signaling, a new era in atopic dermatitis and pruritus therapy has begun. This review highlights new developments in AD treatment, placing a specific focus on their anti-pruritic effects.

Dual function of Langerhans cells in skin TSLP-promoted TFH differentiation in mouse atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is among the most common chronic inflammatory skin diseases, usually occurring early in life, and often preceding other atopic diseases such as asthma. TH2 has been believed to play a crucial role in cellular and humoral response in AD, but accumulating evidence has shown that follicular helper T cell (TFH), a critical player in humoral immunity, is associated with disease severity and plays an important role in AD pathogenesis.

OBJECTIVES

This study aimed at investigating how TFHs are generated during the pathogenesis of AD, particularly what is the role of keratinocyte-derived cytokine TSLP and Langerhans cells (LCs).

METHODS

Two experimental AD mouse models were employed: (1) triggered by the overproduction of TSLP through topical application of MC903, and (2) induced by epicutaneous allergen ovalbumin (OVA) sensitization.

RESULTS

This study demonstrated that the development of TFHs and germinal center (GC) response were crucially dependent on TSLP in both the MC903 model and the OVA sensitization model. Moreover, we found that LCs promoted TFH differentiation and GC response in the MC903 model, and the depletion of Langerin+ dendritic cells (DCs) or selective depletion of LCs diminished the TFH/GC response. By contrast, in the model with OVA sensitization, LCs inhibited TFH/GC response and suppressed TH2 skin inflammation and the subsequent asthma. Transcriptomic analysis of Langerin+ and Langerin- migratory DCs revealed that Langerin+ DCs became activated in the MC903 model, whereas these cells remained inactivated in OVA sensitization model.

CONCLUSIONS

Together, these studies revealed a dual functionality of LCs in TSLP-promoted TFH and TH2 differentiation in AD pathogenesis.

Bidirectional sensory neuron-immune interactions: a new vision in the understanding of allergic inflammation

Peripheral neurons (including sensory neurons) are ubiquitously distributed in all tissues, particularly at the interface with the environment. The primary function of sensory neurons is the transmission of sensations of temperature, pain and itch to elicit appropriate behavioral responses. More recently, sensory neurons have emerged as potent regulators of type 2 immune responses and allergic inflammation. There is increasing evidence showing that neurons can express receptors previously thought to be restricted to the immune compartment. In addition, certain subtypes of immune cells (e.g. mast cells, ILC2s or macrophages) also express specific neuroreceptors that provide them with the capacity to integrate neuron-derived signals and modulate their activation status during the development of allergic inflammation.

Biologics in atopic dermatitis

PURPOSE OF REVIEW

Until recently there have been limited options for systemic therapy in atopic dermatitis, which is unresponsive to topical treatments. However, the last few years have seen a rapid progression in this field. The purpose of this review is to summarise some of the recent literature and ongoing studies in the field of biologicals in atopic dermatitis.

RECENT FINDINGS

Dupilumab has been shown to be effective in moderate to severe atopic dermatitis and is now licensed in the USA and Europe. Tralokinumab is currently under review by the Food and Drug Administration and the European Medicines agency. Phase 2 and 3 studies are taking place with other biological therapies. There is increasing evidence for the use of biologicals in children and for their role in multisystem disease.

SUMMARY

The recent breakthroughs in treatment represent an opportunity to resolve an unmet need; the management of atopic dermatitis which is unresponsive to topical therapy.

The central role of IL-33/IL-1RL1 pathway in asthma: From pathogenesis to intervention

Interleukin-33 (IL-33), a member of the IL-1 family, and its cognate receptor, Interleukin-1 receptor like-1 (IL-1RL1 or ST2), are susceptibility genes for childhood asthma. In response to cellular damage, IL-33 is released from barrier tissues as an 'alarmin' to activate the innate immune response. IL-33 drives type 2 responses by inducing signalling through its receptor IL-1RL1 in several immune and structural cells, thereby leading to type 2 cytokine and chemokine production. IL-1RL1 gene transcript encodes different isoforms generated through alternative splicing. Its soluble isoform, IL-1RL1-a or sST2, acts as a decoy receptor by sequestering IL-33, thereby inhibiting IL1RL1-b/IL-33 signalling. IL-33 and its receptor IL-1RL1 are therefore considered as putative biomarkers or targets for pharmacological intervention in asthma. This review will provide an overview of the genetics and biology of the IL-33/IL-1RL1 pathway in the context of asthma pathogenesis. It will discuss the potential and complexities of targeting the cytokine or its receptor, how genetics or biomarkers may inform precision medicine for asthma targeting this pathway, and the possible positioning of therapeutics targeting IL-33 or its receptor in the expanding landscape of novel biologicals applied in asthma management.

The emerging role of neuroimmune interactions in atopic dermatitis and itch

Millions of people globally suffer from allergic diseases, and the cases have been rising in the past decades. One of the major manifestations of allergic diseases is itch, which is an unpleasant symptom that triggers the urge to scratch and greatly affects the quality of life. Thus, research on how sensation of itch is detected/transmitted from the contact of the allergen to the nervous system is crucial in mitigating itch. Recent studies have attempted to elucidate the mechanisms of itch in allergic diseases. Here, we aim to review the endogenous mediators released from immune/nonimmune skin cells (that are indirectly involved in the propagation of itch) and the sensory neurons that express receptors for these itch mediators that are associated with direct transmission of itch in cutaneous allergic diseases. As the mechanisms for allergic itch become clearer, new therapeutic approaches to relieve itch are likely to be developed. Recent clinical trials are testing numerous compounds that target the endogenous mediators and their receptors. These studies provide the possibility of more effective itch treatment for allergic diseases.

EAACI Biologicals Guidelines-dupilumab for children and adults with moderate-to-severe atopic dermatitis

Atopic dermatitis imposes a significant burden on patients, families and healthcare systems. Management is difficult, due to disease heterogeneity, co-morbidities, complexity in care pathways and differences between national or regional healthcare systems. Better understanding of the mechanisms has enabled a stratified approach to the management of atopic dermatitis, supporting the use of targeted treatments with biologicals. However, there are still many issues that require further clarification. These include the definition of response, strategies to enhance the responder rate, the duration of treatment and its regimen (in the clinic or home-based), its cost-effectiveness and long-term safety. The EAACI Guidelines on the use of dupilumab in atopic dermatitis follow the GRADE approach in formulating recommendations for each outcome and age group. In addition, future approaches and research priorities are discussed.

Biologics and Novel Therapies for Food Allergy

Food allergy is a significant public health burden affecting around 10% of adults and 8% of children. Although the first peanut oral immunotherapy product received Food and Drug Administration approval in 2020, there is still an unmet need for more effective therapeutic options that minimize the risk of anaphylaxis, nutritional deficiencies, and patient's quality of life. Biologics are promising modalities, as they may improve compliance, target multiple food allergies, and treat other concomitant atopic diseases. Although omalizumab has been evaluated extensively, most biologics are more novel and have broader immunologic impact. Careful evaluation of their safety profile should therefore be conducted.

Biological Therapies for Atopic Dermatitis: A Systematic Review

BACKGROUND

Atopic dermatitis (AD) is a widely acquired, relapsing inflammatory skin disease. Biologics are now widely used in patients with moderate-to-severe AD.

OBJECTIVE

This work aims to summarize both label and off-label biologics on AD treatment in phase II and phase III stages, and compile evidence on the efficacy of the most-studied biologics.

METHODS

We conducted a comprehensive literature search through PubMed, EMBASE, and ClinicalTrials.gov to identify all documented biological therapies for AD. The criteria were further refined to focus on those treatments with the highest evidence level for AD with at least one randomized clinical trial supporting their use. Only studies or articles published in English were enrolled in this study.

FINDINGS

Primary searches identified 525 relevant articles and 27 trials. Duplicated articles and papers without a full text were excluded. Only completed trials were enrolled. We included 28 randomized controlled trials, 4 unpublished trials, 2 observational studies, and 1 meta-analysis. Eight kinds of biologics, including IL-4/IL-13 inhibitors, JAK inhibitors, anti-IL-13 antibodies, anti-IL-22 antibodies, anti-IL-33 antibodies, thymic stromal lymphopoietin inhibitor (TSLP), OX40 antibodies, and H4R-antagonists were included in this work. Dupliumab, as the most widely used and investigated biologic, was reported in 1 meta-analysis and 4 trials exploring its long-term use and application in both adults and pediatric patients. Besides dupilumab, four other IL-4/IL-13 inhibitors recruited were all randomized, clinical trials at phase 2-3 stage. Six different kinds of JAK inhibitors were summarized with strong evidence revealing their significant therapeutic effects on AD. There were 3 trials for nemolizumab, an anti-IL-13 antibody, all of which were in the phase 2 clinical trial stage. Results showed nemolizumab could be another alternative therapy for moderate-to-severe AD with long-term efficiency and safety.

CONCLUSION

The biological therapies with the most robust evidence on efficacy and long-term safety for AD treatment include dupilumab, barcitinib, abrocitinib, and delgocitinib. Most of the biologics mentioned in this review were still at the exploratory stage. This review will help practitioners advise patients seeking suitable biological therapies and offer experimental study directions for treatment.

Therapeutic Advances in Diabetes, Autoimmune, and Neurological Diseases

Since 2015, 170 small molecules, 60 antibody-based entities, 12 peptides, and 15 gene- or cell-therapies have been approved by FDA for diverse disease indications. Recent advancement in medicine is facilitated by identification of new targets and mechanisms of actions, advancement in discovery and development platforms, and the emergence of novel technologies. Early disease detection, precision intervention, and personalized treatments have revolutionized patient care in the last decade. In this review, we provide a comprehensive overview of current and emerging therapeutic modalities developed in the recent years. We focus on nine diseases in three major therapeutics areas, diabetes, autoimmune, and neurological disorders. The pathogenesis of each disease at physiological and molecular levels is discussed and recently approved drugs as well as drugs in the clinic are presented.

Turning off the alarm - Targeting alarmins and other epithelial mediators of allergic inflammation with biologics

Besides the major players IL-4, IL-13, IL-5, and IgE as targets for biologics, other mediators have been identified that are secreted by epithelial cells and act upstream in the cascade of allergic inflammation. Such are the alarmin IL-33 as well as TSLP and IL-5. The role of each cytokine in sensitization and effector phase of allergic inflammation and how development of biologics is ongoing in order to inhibit this pathomechanism will be described in the following article.

Involvement of Neuro-Immune Interactions in Pruritus With Special Focus on Receptor Expressions

Pruritus is a common, but very challenging symptom with a wide diversity of underlying causes like dermatological, systemic, neurological and psychiatric diseases. In dermatology, pruritus is the most frequent symptom both in its acute and chronic form (over 6 weeks in duration). Treatment of chronic pruritus often remains challenging. Affected patients who suffer from moderate to severe pruritus have a significantly reduced quality of life. The underlying physiology of pruritus is very complex, involving a diverse network of components in the skin including resident cells such as keratinocytes and sensory neurons as well as transiently infiltrating cells such as certain immune cells. Previous research has established that there is a significant crosstalk among the stratum corneum, nerve fibers and various immune cells, such as keratinocytes, T cells, basophils, eosinophils and mast cells. In this regard, interactions between receptors on cutaneous and spinal neurons or on different immune cells play an important role in the processing of signals which are important for the transmission of pruritus. In this review, we discuss the role of various receptors involved in pruritus and inflammation, such as TRPV1 and TRPA1, IL-31RA and OSMR, TSLPR, PAR-2, NK1R, H1R and H4R, MRGPRs as well as TrkA, with a focus on interaction between nerve fibers and different immune cells. Emerging evidence shows that neuro-immune interactions play a pivotal role in mediating pruritus-associated inflammatory skin diseases such as atopic dermatitis, psoriasis or chronic spontaneous urticaria. Targeting these bidirectional neuro-immune interactions and the involved pruritus-specific receptors is likely to contribute to novel insights into the underlying pathogenesis and targeted treatment options of pruritus.

Keratinocytes: innate immune cells in atopic dermatitis

The skin is a unique immune organ that constitutes a complex network of physical, chemical and microbiological barriers against external insults. Keratinocytes are the most abundant cell type in the epidermis. These cells form the physical skin barrier and represent the first line of the host defense system by sensing pathogens via innate immune receptors, initiating anti-microbial responses and producing various cytokines, chemokines and anti-microbial peptides, which are important events in immunity. A damaged epidermal barrier in atopic dermatitis allows the penetration of potential allergens and pathogens to activate keratinocytes. Among the dysregulation of immune responses in atopic dermatitis, activated keratinocytes play a role in several biological processes that contribute to the pathogenesis of atopic dermatitis. In this review, we summarize the current understanding of the innate immune functions of keratinocytes in the pathogenesis of atopic dermatitis, with a special emphasis on skin-derived anti-microbial peptides and atopic dermatitis-related cytokines and chemokines in keratinocytes. An improved understanding of the innate immunity mediated by keratinocytes can provide helpful insight into the pathophysiological processes of atopic dermatitis and support new therapeutic efforts.

Immunosensation: Neuroimmune Cross Talk in the Skin

Classically, skin was considered a mere structural barrier protecting organisms from a diversity of environmental insults. In recent decades, the cutaneous immune system has become recognized as a complex immunologic barrier involved in both antimicrobial immunity and homeostatic processes like wound healing. To sense a variety of chemical, mechanical, and thermal stimuli, the skin harbors one of the most sophisticated sensory networks in the body. However, recent studies suggest that the cutaneous nervous system is highly integrated with the immune system to encode specific sensations into evolutionarily conserved protective behaviors. In addition to directly sensing pathogens, neurons employ novel neuroimmune mechanisms to provide host immunity. Therefore, given that sensation underlies various physiologies through increasingly complex reflex arcs, a much more dynamic picture is emerging of the skin as a truly systemic organ with highly coordinated physical, immunologic, and neural functions in barrier immunology.

Pharmacokinetic and Pharmacodynamic Modeling of Tezepelumab to Guide Phase 3 Dose Selection for Patients With Severe Asthma

Tezepelumab is a human monoclonal antibody that blocks thymic stromal lymphopoietin, an epithelial cytokine involved in asthma pathogenesis. In the phase 2b PATHWAY study (ClinicalTrials.gov identifier: NCT02054130), tezepelumab significantly reduced exacerbations in adults with severe, uncontrolled asthma. We used pharmacokinetic (PK) and pharmacodynamic (PD) modeling to guide tezepelumab dose selection for phase 3 trials in patients with severe asthma. PK data from 7 clinical studies were used to develop a population PK model. Population PK-PD models were developed to characterize the relationship between tezepelumab PK and asthma exacerbation rate (AER) and fractional exhaled nitric oxide (FeNO) levels (using phase 2b PD data only). Tezepelumab PK were well described by a 2-compartment model with first-order absorption; PK parameter estimates were consistent with those of other immunoglobulin G2 antibodies. PK-PD models predicted that subcutaneous dosing at 210 mg every 4 weeks was associated with ≈90% of the maximum drug effect of tezepelumab on AER and FeNO; further dose increases were not expected to result in additional, clinically meaningful treatment benefit. No clinically significant covariates of treatment effects on AER and FeNO were identified. Population PK simulations, exposure-response relationships and safety profiles of tezepelumab at doses up to 280 mg every 2 weeks suggested that no dose adjustment based on body weight or for adolescents was required. These results support the selection of 210 mg every 4 weeks subcutaneously as the dose for phase 3 studies of tezepelumab in adults and adolescents with severe asthma.

Thymic Stromal Lymphopoietin Promotes MRGPRX2-Triggered Degranulation of Skin Mast Cells in a STAT5-Dependent Manner with Further Support from JNK

Thymic stromal lymphopoietin (TSLP) is released by epithelial cells following disturbed homeostasis to act as “alarmin” and driver of Th2-immunity. Aberrant TSLP expression is a hallmark of atopic diseases, including atopic dermatitis (AD). Mast cells (MCs) are overabundant in AD lesions and show signs of degranulation, but it remains unknown whether TSLP contributes to granule discharge. Degranulation of skin MCs proceeds via two major routes, i.e., FcεRI-dependent (allergic) and MRGPRX2-mediated (pseudo-allergic/neurogenic). Evidence is accumulating that MRGPRX2 may be crucial in the context of skin diseases, including eczema. The current study reveals TSLP as a novel priming factor of human skin MCs. Interestingly, TSLP selectively cooperates with MRGPRX2 to support granule discharge, while it does not impact spontaneous or FcεRI-driven exocytosis. TSLP-assisted histamine liberation triggered by compound 48/80 or Substance P, two canonical MRGPRX2 agonists, was accompanied by an increase in CD107a+ cells (a MC activation marker). The latter process was less potent, however, and detectable only at the later of two time points, suggesting TSLP may prolong opening of the granules. Mechanistically, TSLP elicited phosphorylation of STAT5 and JNK in skin MCs and the reinforced degranulation critically depended on STAT5 activity, while JNK had a contributory role. Results from pharmacological inhibition were confirmed by RNA-interference, whereby silencing of STAT5 completely abolished the priming effect of TSLP on MRGPRX2-mediated degranulation. Collectively, TSLP is the first factor to favor MRGPRX2- over FcεRI-triggered MC activation. The relevance of TSLP, MCs and MRGPRX2 to pruritis and atopic skin pathology indicates broad repercussions of the identified connection.

Global differences in atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disorder, with a highly variable prevalence worldwide. Recent evidence, however, has shown an increase in prevalence in the Asia Pacific region. Nevertheless, most of the published literature has focused mainly on Western populations, and only few clinical trials have included subgroups of other ethnic populations. Reasons for the observed ethnic and geographical differences in AD are not well established. This calls into question the need for a better understanding of AD pathogenesis and inter-ethnic differences in clinical and immuno-phenotypes. These differences may reflect inherent variability in disease mechanisms between populations, which in turn may impact upon treatment responses such as biologics that are currently tailored mainly to a specific immuno-phenotype (T-helper type 2 dominant). In this article, we reviewed existing literature on the prevalence of AD globally, highlighting differences, if any, in the clinical and immuno-phenotypes of AD between different ethnicities. We discussed genetic and environmental factors that affect AD in different populations and therapeutic considerations. Our review highlights AD as a disease with ethnic-dependent clinical and immunological heterogeneity and calls for greater inclusion of ethnic diversity in future research in order to develop targeted treatments.

Therapeutic New Era for Atopic Dermatitis: Part 1. Biologics

Atopic dermatitis (AD) is a chronic, inflammatory cutaneous disease driven by immune dysregulation and skin barrier dysfunction. We are currently experiencing a new era of understanding of the pathogenesis of AD and, as a consequence, a new era of innovation in therapeutics, including small molecules and biologic therapy. Recently, advances in translational research have challenged the traditional AD pathogenesis paradigm of AD being solely a Th2-dominant disease. Other immune pathways seem to play a role in the complex AD pathophysiology, although the clinical relevance of these additional immune pathway abnormalities is unclear. Type 1, type 22, and type 17 pathway activation (with related cytokines/chemokines) have been demonstrated in the skin and blood of AD patients. Type 2 (interleukin [IL]-4, IL-13), IL-31, and type 22 (IL-22) pathway cytokines are increased in AD acute lesions. IL-22 induces both an epidermal hyperplasia at the onset of acute AD and a marked increase in the terminal differentiation S100 genes. This understanding of pathogenesis corresponds to a historic increase in therapeutic development in AD. The extreme clinical heterogeneity and the chronic progression of AD establish the need for newer, safer, and more effective treatments, control the disease, and improve the quality of life of affected patients.

Therapeutic targeting of the IL-13 pathway in skin inflammation

Introduction: Atopic dermatitis (AD) is a heterogeneous, chronic, inflammatory skin disease with a non-negligible prevalence at present. Its pathogenesis is complex, but mainly characterized by constitutive T helper type 2 (Th2)-cell activation. Systemic therapies for moderate-to-severe AD can be associated with adverse events that encumber their satisfactory long-term use. Several drugs targeting relevant molecules in the immunopathogenesis of AD have been approved or are under clinical development for the treatment of moderate to severe AD. To elaborate this review, literature searches were performed in PubMed on 29 August 2020.Areas covered: This narrative literature review is focused on the pivotal role of IL-13 in the immunopathogenesis of AD and other skin diseases.Expert opinion: Dupilumab has demonstrated the central role of IL-13 and IL-4 in the pathogenesis of AD, asthma, and other diseases in the atopic spectrum. In addition, phase III randomized clinical trials (RCTs) evaluating specific blockade of IL-13 with tralokinumab for treatment of AD also demonstrated favorable results, and phase III RCT evaluating lebrikizumab are ongoing. The role of IL-13 in other skin diseases should be further investigated.