Efficacy and safety of ustekinumab treatment in adults with moderate-to-severe atopic dermatitis

Interleukin antagonists for atopic dermatitis: a new era of therapy

INTRODUCTION

Over the last decade, increasing understanding of the immunopathogenesis of atopic dermatitis (AD) enabled the recognition of multiple therapeutic targets and subsequently the development of novel, highly effective systemic treatments, including interleukin (IL)-antagonists. To date, the IL-4Ra-inhibitor dupilumab and the IL-13 inhibitor tralokinumab have gained regulatory approval in Europe for the treatment of moderate-to-severe AD, while more than 70 new therapeutics are currently in development.

AREAS COVERED

In this review, we address the role of ILs in the pathogenesis of AD and provide an overview of the novel and investigational IL-antagonists, as regards their efficacy and safety on moderate-to-severe AD.

EXPERT OPINION

Current data have established IL-4 and IL-13 inhibitors as effective and safe for the treatment of moderate-to-severe AD, as regards the rapid control of flares as well as the long-term remission of the disease. Data regarding the efficacy and safety of other IL-inhibitors, including those targeting IL-31, IL-22, IL-33, IL-36 and IL-18, are accumulating. There is still an unmet need for real-world-evidence studies and head-to-head studies for both currently available and future agents in AD treatment. Establishing predictive biomarkers of treatment response in a disorder of such considerable heterogenicity might help physicians pursue a patient-tailored therapeutic response.

Integrating multi-omics approaches in deciphering atopic dermatitis pathogenesis and future therapeutic directions

Atopic dermatitis (AD), a complex and heterogeneous chronic inflammatory skin disorder, manifests in a spectrum of clinical subtypes. The application of genomics has elucidated the role of genetic variations in predisposing individuals to AD. Transcriptomics, analyzing gene expression alterations, sheds light on the molecular underpinnings of AD. Proteomics explores the involvement of proteins in AD pathophysiology, while epigenomics examines the impact of environmental factors on gene expression. Lipidomics, which investigates lipid profiles, enhances our understanding of skin barrier functionalities and their perturbations in AD. This review synthesizes insights from these omics approaches, highlighting their collective importance in unraveling the intricate pathogenesis of AD. The review culminates by projecting future trajectories in AD research, particularly the promise of multi-omics in forging personalized medicine and novel therapeutic interventions. Such an integrated multi-omics strategy is poised to transform AD comprehension and management, steering towards more precise and efficacious treatment modalities.

Treatment of atopic dermatitis: Recently approved drugs and advanced clinical development programs

Atopic dermatitis (AD) represents the most common skin disease characterized by heterogeneous endophenotypes and a high disease burden. In Europe, six new systemic therapies for AD have been approved: the biologics dupilumab (anti-interleukin-4 receptor (IL-4R) α in 2017), tralokinumab (anti-IL-13 in 2021), lebrikizumab (anti-IL-13 in 2023), and the oral janus kinase (JAK) inhibitors (JAKi) targeting JAK1/2 (baricitinib in 2020 in the EU) or JAK1 (upadacitinib in 2021 and abrocitinib in 2022). Herein, we give an update on new approvals, long-term safety, and efficacy. Upadacitinib and abrocitinib have the highest short-term efficacy among the approved systemic therapies. In responders, dupilumab and tralokinumab catch up regarding long-term efficacy and incremental clinical benefit within continuous use. Recently, the European Medicines Agency has released recommendations for the use of JAKi in patients at risk (cardiovascular and thromboembolic diseases, malignancies, (former) smoking, and age ≥65 years). Furthermore, we give an overview on emerging therapies currently in Phase III trials. Among the topical therapies, tapinarof (aryl hydrocarbon receptor), ruxolitinib (JAK1/2i), delgocitinib (pan-JAKi), asivatrep (anti-transient receptor potential vanilloid), and phosphodiesterase-4-inhibitors (roflumilast, difamilast) are discussed. Among systemic therapies, current data on cord-blood-derived mesenchymal stem cells, CM310 (anti IL-4Rα), nemolizumab (anti-IL-31RA), anti-OX40/OX40L-antibodies, neurokinin-receptor-1-antagonists, and difelikefalin (κ-opioid-R) are reported.

Biologic and small-molecule therapy for treating moderate to severe atopic dermatitis: Mechanistic considerations

Atopic dermatitis (AD) is a complex and heterogeneous skin disease for which achieving complete clinical clearance for most patients has proven challenging through single cytokine inhibition. Current studies integrate biomarkers and evaluate their role in AD, aiming to advance our understanding of the diverse molecular profiles implicated. Although traditionally characterized as a TH2-driven disease, extensive research has recently revealed the involvement of TH1, TH17, and TH22 immune pathways as well as the interplay of pivotal immune molecules, such as OX40, OX40 ligand (OX40L), thymic stromal lymphopoietin, and IL-33. This review explores the mechanistic effects of treatments for AD, focusing on mAbs and Janus kinase inhibitors. It describes how these treatments modulate immune pathways and examines their impact on key inflammatory and barrier biomarkers.

Potential Aspects of the Use of Cytokines in Atopic Dermatitis

Atopic dermatitis (AD) is an abnormal inflammatory response in the skin to food, environmental IgE, or non-IgE allergens. This disease belongs to a group of inflammatory diseases that affect both children and adults. In highly developed countries, AD is diagnosed twice as often in children than in adults, which may possibly be connected to increased urbanization. The immune system's pathomechanisms of AD involve humoral mechanisms with IgE, cellular T lymphocytes, dendritic cells occurring in the dermis, Langerhans cells occurring in the epidermis, and other cells infiltrating the site of inflammation (eosinophils, macrophages, mast cells, neutrophils, and basophils). Cytokines are small proteins that affect the interaction and communication between cells. This review characterizes cytokines and potential aspects of the treatment of atopic dermatitis, as well as new strategies that are currently being developed, including targeting cytokines and their receptors.

Psoriasis dermatitis: a new entity or a different phenotypic expression of psoriasis and atopic dermatitis?

BACKGROUND

Psoriasis (P) and atopic dermatitis (AD) share some common characteristics. The resulting clinical picture with shared manifestations is a new entity called psoriasis dermatitis (PD), atopic psoriasis or psorema. The purpose of this study was to identify the clinical manifestations of this new dermatological condition, focusing on the adult population.

METHODS

We recruited adult patients from two outpatient clinics, the "severe psoriasis" and the "adult atopic dermatitis," between January 1st, 2021, and December 31st, 2021. The 26 patients meeting the inclusion criteria were followed for 12 months, and two control groups of patients were enrolled in the same period.

RESULTS

The frequencies of the variables examined within the patients affected by PD were compared with those of P or AD group. The age at disease onset was significantly higher in PD patients and the duration of symptoms was also significantly lower in PD patients, compared to both P and AD groups. Affected areas were similar between PD and P, instead the scalp, feet and genitals were more frequently involved in the PD group than in the AD group.

CONCLUSIONS

P and AD seem part of a spectrum rather than a dichotomy, where PD is an entity in the middle of this spectrum.

Off-label use of Baricitinib improves moderate and severe atopic dermatitis in China through inhibiting MAPK and PI3K/Akt/mTOR pathway via targeting JAK-STAT signaling of CD4+ cells

As an inflammatory disease with a disrupted immune system, cytokine disorders in atopic dermatitis (AD) are closely related to the abnormal activation of JAK-STAT signal pathway. The critical relevance of the JAK-STAT signaling pathway to the pathogenesis of AD provides a strong rationale for JAK inhibitor research. Baricitinib, a small-molecule oral JAK inhibitor, has been proven to inhibit JAK-STAT signaling in a variety of diseases, including AD. It is currently available in China for off-label use. However, its efficacy in China and its mechanism are rarely reported. In our study, we found that the immune status of patients with moderate and severe AD was hyperactive. Among the 49 known immunotherapy targets, JAK1 and JAK2 genes on lymphocytes of AD patients were significantly upregulated, which was closely related to the symptom severity in moderate and severe AD patients. Baricitinib can improve immune hyperresponsiveness and clinical symptoms in moderate and severe AD by inhibiting the activation of Th2 cell subsets and the secretion of Th2-type cytokines through MAPK, mTOR and PI3K-Akt signaling pathways, providing an important theoretical basis for clinical off-label use of Baricitinib to treat moderate and severe AD.

Diversity of atopic dermatitis and selection of immune targets

Atopic dermatitis (AD) is a heterogeneous immune-mediated skin disorder affecting people of all ages and ethnicities. Despite the development of targeted therapeutics such as biologics and Janus kinase inhibitors, attaining complete clinical efficacy remains difficult. This therapeutic challenge may be attributed to the complex pathogenesis of AD. Although the TH2 axis has been extensively studied, recent advancements have started to reveal the involvement of additional immune pathways including TH1, TH17, and TH22. Understanding the interplay of these immune axes may contribute to a more personalized therapeutic approach based on patients' molecular profile, with the prospect of improving clinical outcome. This review will discuss studies exploring the molecular profile of AD in both skin and blood across age, ethnicity/race, disease chronicity, IgE levels, filaggrin mutation status, and AD association with other atopic conditions. Moreover, it will explore the potential of personalized treatment strategies based on a patient's distinct immune signature.

Systemic treatments for atopic dermatitis (eczema): Systematic review and network meta-analysis of randomized trials

BACKGROUND

Atopic dermatitis (AD) is an inflammatory skin condition with multiple systemic treatments and uncertainty regarding their comparative impact on AD outcomes.

OBJECTIVE

We sought to systematically synthesize the benefits and harms of AD systemic treatments.

METHODS

For the 2023 American Academy of Allergy, Asthma & Immunology and American College of Allergy, Asthma, and Immunology Joint Task Force on Practice Parameters AD guidelines, we searched MEDLINE, EMBASE, CENTRAL, Web of Science, and GREAT databases from inception to November 29, 2022, for randomized trials addressing systemic treatments and phototherapy for AD. Paired reviewers independently screened records, extracted data, and assessed risk of bias. Random-effects network meta-analyses addressed AD severity, itch, sleep, AD-related quality of life, flares, and harms. The Grading of Recommendations Assessment, Development and Evaluation approach informed certainty of evidence ratings. This review is registered in the Open Science Framework (https://osf.io/e5sna).

RESULTS

The 149 included trials (28,686 patients with moderate-to-severe AD) evaluated 75 interventions. With high-certainty evidence, high-dose upadacitinib was among the most effective for 5 of 6 patient-important outcomes; high-dose abrocitinib and low-dose upadacitinib were among the most effective for 2 outcomes. These Janus kinase inhibitors were among the most harmful in increasing adverse events. With high-certainty evidence, dupilumab, lebrikizumab, and tralokinumab were of intermediate effectiveness and among the safest, modestly increasing conjunctivitis. Low-dose baricitinib was among the least effective. Efficacy and safety of azathioprine, oral corticosteroids, cyclosporine, methotrexate, mycophenolate, phototherapy, and many novel agents are less certain.

CONCLUSIONS

Among individuals with moderate-to-severe AD, high-certainty evidence demonstrates that high-dose upadacitinib is among the most effective in addressing multiple patient-important outcomes, but also is among the most harmful. High-dose abrocitinib and low-dose upadacitinib are effective, but also among the most harmful. Dupilumab, lebrikizumab, and tralokinumab are of intermediate effectiveness and have favorable safety.

The role of Janus kinase signaling in the pathology of atopic dermatitis

Atopic dermatitis (AD) is a heterogeneous, chronic, relapsing, inflammatory skin disease associated with considerable physical, psychological, and economic burden. The pathology of AD includes complex interactions involving abnormalities in immune and skin barrier genes, skin barrier disruption, immune dysregulation, microbiome disturbance, and other environmental factors. Many of the cytokines involved in AD pathology, including IL-4, IL-13, IL-22, IL-31, thymic stromal lymphopoietin, and IFN-γ, signal through the Janus kinase (JAK)-signal transducer and activation of transcription (STAT) pathway. The JAK family includes JAK1, JAK2, JAK3, and tyrosine kinase 2; the STAT family includes STAT1, STAT2, STAT3, STAT4, STAT5A/B, and STAT6. Activation of the JAK-STAT pathway has been implicated in the pathology of several immune-mediated inflammatory diseases, including AD. However, the exact mechanisms of JAK-STAT involvement in AD have not been fully characterized. This review aims to discuss current knowledge about the role of the JAK-STAT signaling pathway and, specifically, the role of JAK1 in the pathology and symptomology of AD.

Multifaceted analysis of cross-tissue transcriptomes reveals phenotype-endotype associations in atopic dermatitis

Atopic dermatitis (AD) is a skin disease that is heterogeneous both in terms of clinical manifestations and molecular profiles. It is increasingly recognized that AD is a systemic rather than a local disease and should be assessed in the context of whole-body pathophysiology. Here we show, via integrated RNA-sequencing of skin tissue and peripheral blood mononuclear cell (PBMC) samples along with clinical data from 115 AD patients and 14 matched healthy controls, that specific clinical presentations associate with matching differential molecular signatures. We establish a regression model based on transcriptome modules identified in weighted gene co-expression network analysis to extract molecular features associated with detailed clinical phenotypes of AD. The two main, qualitatively differential skin manifestations of AD, erythema and papulation are distinguished by differential immunological signatures. We further apply the regression model to a longitudinal dataset of 30 AD patients for personalized monitoring, highlighting patient heterogeneity in disease trajectories. The longitudinal features of blood tests and PBMC transcriptome modules identify three patient clusters which are aligned with clinical severity and reflect treatment history. Our approach thus serves as a framework for effective clinical investigation to gain a holistic view on the pathophysiology of complex human diseases.

The pathogenetic role of Th17 immune response in atopic dermatitis

PURPOSE OF REVIEW

As we continue to unravel the pathophysiology and immune mechanisms underlying atopic dermatitis (AD), the emergence of targeted treatments has provided new options for management. Although there are available therapies targeting various immune pathways in AD, the precise pathogenic role of interleukin (IL)-17 in AD pathogenesis remains unclear. The objective of this review is to examine the existing data pertaining to the role of IL-17 in AD and shed light on the potential of targeting this pathway as a therapeutic approach in AD treatment.

RECENT FINDINGS

IL-17 has a dual role of pro-inflammatory and immune protective function, making it an important player in several autoimmune and inflammatory conditions. The extent of IL-17 axis involvement in AD pathogenesis is still debatable. Emerging data show that Th17-related cytokines/chemokines are elevated in skin and sera samples of AD patients, with some articles reporting correlations with disease severity. Particularly increased Th17 signature in specific AD patient subsets, such as Asian-origin or pediatric patients, suggests that certain patients' disease presentations are more predominantly influenced by Th17, and, thus, they may benefit more from Th17 therapeutic targeting approaches. Lack of clinical efficacy with anti-Th17 biologics in AD patients, underscores the need to better elucidate the role of Th17 in AD pathogenesis, along with its utility in therapy.

SUMMARY

The well established role of IL-17 in autoimmune disorders hints for its possible participation in AD disease pathogenesis. Subsequent investigations are needed to assess whether the targeting of specific IL-17 isoforms, homodimers, or heterodimers in specific subpopulations of AD can modify treatment outcomes.

Atopic dermatitis: a brief review of recent advances in its management

Atopic dermatitis (AD) is a common inflammatory skin disorder characterized by recurrent eczematous lesions and intense itching. The disorder affects people of all ages and ethnicities, has a substantial psychosocial impact on patients and relatives, and is the leading cause of the global burden of skin diseases. Atopic dermatitis is associated with an increased risk of multiple comorbidities, including food allergies, asthma, allergic rhinitis, and mental health disorders. The pathophysiology is complex and involves a strong genetic predisposition, epidermal dysfunction, and T-cell-driven inflammation. Although type-2 mechanisms are dominant, there is increasing evidence that the disorder involves multiple immune pathways. Until recently, the management of AD rested mainly on the judicious use of emollients, topical steroids, and topical calcineurin inhibitors in the majority of patients, and systemic immunosuppressants were advocated in severely diseased patients. However, in the last few years, new therapeutic strategies have been designed and developed to target the various steps in the chain of molecular events that lead to the AD phenotype. This review highlights the recent advancements in the management of AD.

Anti-inflammatory and biologic drugs for atopic dermatitis: a therapeutic approach in children and adolescents

Atopic dermatitis (AD) is a chronic inflammatory disease with a heterogeneous pathogenesis correlated with dysregulation of the immune system and a prevalence of the T2-mediated immune pathway. Recent understanding of the pathogenesis of AD has allowed the development of new drugs targeting different mechanisms and cytokines that have changed the treatment approach. The aim of this review is to update knowledge on the standard of care and recent advancements in the control of skin inflammation. In light of recent guidelines, we report on the clinical efficacy of novel treatments, with special attention to situations where biologics and small molecules are involved.

The IL-4Rα Q576R polymorphism is associated with increased severity of atopic dermatitis and exaggerates allergic skin inflammation in mice

BACKGROUND

Atopic dermatitis (AD) is characterized by TH2-dominated skin inflammation and systemic response to cutaneously encountered antigens. The TH2 cytokines IL-4 and IL-13 play a critical role in the pathogenesis of AD. The Q576->R576 polymorphism in the IL-4 receptor alpha (IL-4Rα) chain common to IL-4 and IL-13 receptors alters IL-4 signaling and is associated with asthma severity.

OBJECTIVE

We sought to investigate whether the IL-4Rα R576 polymorphism is associated with AD severity and exaggerates allergic skin inflammation in mice.

METHODS

Nighttime itching interfering with sleep, Rajka-Langeland, and Eczema Area and Severity Index scores were used to assess AD severity. Allergic skin inflammation following epicutaneous sensitization of mice 1 or 2 IL-4Rα R576 alleles (QR and RR) and IL-4Rα Q576 (QQ) controls was assessed by flow cytometric analysis of cells and quantitative RT-PCR analysis of cytokines in skin.

RESULTS

The frequency of nighttime itching in 190 asthmatic inner-city children with AD, as well as Rajka-Langeland and Eczema Area and Severity Index scores in 1116 White patients with AD enrolled in the Atopic Dermatitis Research Network, was higher in subjects with the IL-4Rα R576 polymorphism compared with those without, with statistical significance for the Rajka-Langeland score. Following epicutaneous sensitization of mice with ovalbumin or house dust mite, skin infiltration by CD4+ cells and eosinophils, cutaneous expression of Il4 and Il13, transepidermal water loss, antigen-specific IgE antibody levels, and IL-13 secretion by antigen-stimulated splenocytes were significantly higher in RR and QR mice compared with QQ controls. Bone marrow radiation chimeras demonstrated that both hematopoietic cells and stromal cells contribute to the mutants' exaggerated allergic skin inflammation.

CONCLUSIONS

The IL-4Rα R576 polymorphism predisposes to more severe AD and increases allergic skin inflammation in mice.

The translational revolution in atopic dermatitis: the paradigm shift from pathogenesis to treatment

Atopic dermatitis (AD) is the most common inflammatory skin disease, and it is considered a complex and heterogeneous condition. Different phenotypes of AD, defined according to the patient age at onset, race, and ethnic background; disease duration; and other disease characteristics, have been recently described, underlying the need for a personalized treatment approach. Recent advancements in understanding AD pathogenesis resulted in a real translational revolution and led to the exponential expansion of the therapeutic pipeline. The study of biomarkers in clinical studies of emerging treatments is helping clarify the role of each cytokine and immune pathway in AD and will allow addressing the unique immune fingerprints of each AD subset. Personalized medicine will be the ultimate goal of this targeted translational research. In this review, we discuss the changes in the concepts of both the pathogenesis of and treatment approach to AD, highlight the scientific rationale behind each targeted treatment and report the most recent clinical efficacy data.

Spesolimab, an anti-interleukin-36 receptor antibody, in patients with moderate-to-severe atopic dermatitis: Results from a multicentre, randomized, double-blind, placebo-controlled, phase IIa study

BACKGROUND

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease, and there is increasing evidence that the interleukin (IL)-36 pathway may play a role in the pathogenesis of AD.

OBJECTIVES

To evaluate the efficacy and safety of spesolimab, a novel anti-IL-36 receptor antibody, in adult patients with moderate-to-severe AD.

METHODS

In this phase IIa study, 51 eligible patients were randomized 2:1 to receive intravenous doses of spesolimab 600 mg or placebo every 4 weeks. The primary endpoint was the percentage change from baseline in Eczema Area and Severity Index (EASI) score at Week 16.

RESULTS

The decrease in EASI score from baseline to Week 16 was -37.9% for spesolimab versus -12.3% for placebo (adjusted mean difference -25.6%, p = 0.149). A predefined sensitivity analysis, excluding data from patients who used restricted corticosteroids, resulted in an adjusted mean difference of -48.3% (nominal p = 0.024). Spesolimab was well tolerated, with no clinically relevant safety signals.

CONCLUSIONS

This is the first study to evaluate the IL-36 pathway inhibition in AD. Although not statistically significant, numerical improvements were observed in the primary endpoint of change from baseline in the EASI score. Spesolimab had an acceptable safety profile, with no unexcepted safety concerns.

Eczematized psoriasis - a frequent but often neglected variant of plaque psoriasis

Psoriasis is a common chronic inflammatory skin disease that causes systemic inflammation and severely impacts the patient's quality of life. Several highly effective therapeutics for psoriasis have been approved in recent years. However, in real life, a high proportion of patients either do not experience the clinical improvement observed in clinical trials or develop a secondary loss of efficacy. This may be a result of unrecognized endotypes of psoriasis that need to be characterized in greater depth to enable selection of an appropriate therapy. Eczematized psoriasis, which occurs in approximately 5-10% of patients with psoriasis, is an often-neglected variant of psoriasis. The term "eczematized psoriasis" refers to patients developing psoriasis with similarities to eczema. These patients typically present with severe itching, and skin biopsies often reveal eosinophil granulocytes, serum crusts, or spongiosis, which are frequently observed in eczema. From an immunological perspective, additional signaling pathways that are responsible for eczema reactions might be activated in eczematized psoriasis compared to classical plaque psoriasis. This review summarizes the key clinical, histological, and immunological features of eczematized psoriasis, proposes diagnostic criteria, and evaluates the therapeutic options for eczematized psoriasis.

The evolving landscape of biologic therapies for atopic dermatitis: Present and future perspective

Atopic dermatitis (AD) is one of the most common, chronic inflammatory skin diseases with a significant physical, emotional and socioeconomic burden. In recent years the understanding of AD pathogenesis has expanded from the Th2-centred perspective, with the recognition of the involvement of other immune axes. In different AD endotypes, influenced by environment, genetics and race, transcriptomic profiles have identified differing contributions of multiple immune axes such as, Th17, Th22 and Th1. The enriched pathogenic model of AD has catalysed the development of numerous biologic therapies targeting a range of key molecules implicated in disease progression. Currently, dupilumab and tralokinumab, which both target the Th2 pathway, are the only approved biologic therapies for AD in the United States and Europe. New biologic therapies in development, however, target different Th2-pathway molecules along with cytokines in other immune axes, including Th17 and Th22, offering promise for varied treatments for this heterogeneous disease. As the biologic pipeline advances, the integration into clinical practice and approval of these experimental biologics may provide more effective, tailored therapeutic solutions and illuminate on the pathologic processes of AD across a broader, more diverse patient population.

Advances in Current Drugs and Formulations for the Management of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disease with a complex pathophysiology. Treatment of AD remains challenging owing to the presence of a wide spectrum of clinical phenotypes and limited response to existing therapies. However, recent genetic, immunological, and pathophysiological insights into the disease mechanism resulted in the invention of novel therapeutic drug candidates. This review provides a comprehensive overview of current therapies and assesses various novel drug delivery strategies currently under clinical investigation. Further, this review majorly emphasizes on various topical treatments including emollient therapies, barrier repair agents, topical corticosteroids (TCS), phosphodiesterase 4 (PDE4) inhibitors, calcineurin inhibitors, and Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway inhibitors. It also discusses biological and systemic therapies, upcoming treatments based on ongoing clinical trials. Additionally, this review scrutinized the use of pharmaceutical inactive ingredients in the approved topical dosage forms for AD treatment.

Off-label uses of ustekinumab

Ustekinumab (brand name Stelara®) is a human interleukin-12 and -23 antagonist and has been indicated for the treatments of moderate to severe plaque psoriasis, psoriatic arthritis, Crohn's disease and ulcerative colitis. This review aims to synthesize and interpret the literature evaluating the off-label uses of ustekinumab. We performed searches in PubMed and ClinicalTrials.gov for clinical trials, observational studies, case series, and case reports evaluating label uses of ustekinumab. Studies evaluated the efficacy of ustekinumab for the following conditions: other types of psoriasis (expect plaque psoriasis and psoriatic arthritis), pityriasis rubra pilaris, hidradenitis suppurativa, atopic dermatitis, pyoderma gangrenosum, et al. Based on the available literature, ustekinumab appears to be a potential treatment choice for many other diseases. However, more clinical trials data are needed to adequately assess the safety and efficacy of ustekinumab for the treatment of these conditions.

Insights into atopic dermatitis pathogenesis lead to newly approved systemic therapies

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by scaly, oozing skin and itch. In moderate-to-severe AD, treatment options have been historically very limited and off-label use has been a common method for disease management. For decades, ciclosporin A was the only systemic immunosuppressive drug approved in most European countries to address this major unmet medical need. However, increased understanding of the pathophysiology of AD has led to a revolution in the treatment of this potentially debilitating disease. Following the approval of the first biological therapy for AD in 2017, there has been a rapid expansion of compounds under development and four additional systemic therapies have been approved in Europe and the USA within the past 3 years alone. In this review, we underscore how key breakthroughs have transformed the therapeutic landscape of AD, leading to a major expansion of type 2 immunity-targeted biological therapies, exploration of neuroimmune modulatory agents, and interest in Janus kinase inhibition.

Critical Players and Therapeutic Targets in Chronic Itch

Chronic itch is one of the most prominent clinical characteristics of diverse systematic diseases. It is a devastating sensation in pathological diseases. Despite its importance, there are no FDA-labelled drugs specifically geared toward chronic itch. The associated complex pathogenesis and diverse causes escalate chronic itch to being one of the top challenges in healthcare. Humanized antibodies against IL-13, IL-4, and IL-31 proved effective in treatment of itch-associated atopic dermatitis but remain to be validated in chronic itch. There are still no satisfactory anti-itch therapeutics available toward itch-related neuropeptides including GRP, BNP, SST, CGRP, and SP. The newly identified potential itch targets including OSM, NMB, glutamate, periostin, and Serpin E1 have opened new avenues for therapeutic development. Proof-of-principle studies have been successfully performed on antagonists against these proteins and their receptors in itch treatment in animal models. Their translational interventions in humans need to be evaluated. It is of great importance to summarize and compare the newly emerging knowledge on chronic itch and its pathways to promote the development of novel anti-itch therapeutics. The goal of this review is to analyze the different physiologies and pathophysiologies of itch mediators, whilst assessing their suitability as new targets and discussing future therapeutic development.

Racial and Ethnic Diversity of US Participants in Clinical Trials for Acne, Atopic Dermatitis, and Psoriasis: A Comprehensive Review

An increasing body of literature describes underreporting of race and ethnicity, and overrepresentation of White individuals in clinical trials. We aimed to evaluate the racial and ethnic diversity of US participants in clinical trials for acne, atopic dermatitis (AD), and psoriasis. We performed a comprehensive review of clinical trials for these common dermatologic diseases that were published between January 2014 and July 2019. Race and ethnicity reporting among all trials, and the racial and ethnic distribution of US participants were compared by skin disease, intervention type, and trial phase. In total, 103 articles representing 119 unique trials were evaluated. Race and ethnicity were reported in only 22.7% of trials. The proportion of White participants (77.5%) was higher than that of the US population (72.5%, p < 0.01); a finding largely driven by psoriasis trials (84.7% White). The proportions of non-White and Hispanic individuals in non-topical (21.0% and 16.3%, respectively) and phase III (20.5% and 18.7%, respectively) trials were lower than those in topical (23.5% and 23.3%, respectively; p < 0.01) and phase I/II trials (25.6% and 22.3%, respectively; p < 0.01). Race and ethnicity remain underreported in dermatologic clinical trials, and US trial participant diversity differs by skin disease, intervention type, and trial phase.

Atopic dermatitis: pathomechanisms and lessons learned from novel systemic therapeutic options

Atopic dermatitis (AD) is a chronic, heterogenous, inflammatory skin disorder associated with a high skin-related health burden, typically starting in childhood and often persisting into adulthood. AD is characterized by a wide range of clinical phenotypes, reflecting multiple underlying pathophysiological mechanisms and interactions between genetics, immune system dysregulation, and environmental factors. In this review, we describe the diverse cellular and molecular mechanisms involved in AD, including the critical role of T cell-driven inflammation, primarily via T helper (Th) 2- and Th17-derived cytokines, many of which are mediated by the Janus kinase (JAK) signaling pathway. These local inflammatory processes interact with sensory neuronal pathways, contributing to the clinical manifestations of AD, including itch, pain, and sleep disturbance. The recent elucidation of the molecular pathways involved in AD has allowed treatment strategies to evolve from broad-acting systemic immunosuppressive therapies to more targeted agents, including JAK inhibitors and cytokine-specific biologic agents. Evidence from the clinical development of these targeted therapies has reinforced and expanded our understanding of the pathophysiological mechanisms underlying AD and holds promise for individualized treatment strategies tailored to specific AD subtypes.

Adipose-derived stem cells ameliorate atopic dermatitis by suppressing the IL-17 expression of Th17 cells in an ovalbumin-induced mouse model

Background

Mesenchymal stem cells (MSCs) have therapeutic potential for atopic dermatitis (AD) owing to their immunoregulatory effects. However, the underlying mechanisms associated with the therapeutic efficacy of MSCs on AD are diverse and related to both cell type and delivery method.

Objectives

This study investigated the therapeutic effect and mechanisms of adipose-derived stem cells (ADSCs) on AD using an ovalbumin (OVA)-induced AD mouse model.

Methods

AD mice were subcutaneously injected with mouse ADSCs, cortisone, or PBS, and the therapeutic effects were determined by gross and histological examinations and serum IgE levels. Additionally, qPCR, RNA-sequencing analyses of skin samples and co-culture of ADSCs and Th17 cells were conducted to explore the underlying therapeutic mechanisms.

Results

ADSCs treatment attenuated the AD pathology, decreased the serum IgE levels, and decreased mast cells infiltration in the skin of the model mice. Moreover, tissue levels of IL-4R and Th17-relevant products (IL-17A, CCL20, and MMP12) were suppressed in the ADSC- and cortisone-treated groups. Genomics and bioinformatics analyses demonstrated significant enrichment of inflammation-related pathways in the downregulated genes of the ADSC- and cortisone-treated groups, specifically the IL-17 signaling pathway. Co-culture experiments revealed that ADSCs significantly suppressed the proliferation of Th17 cells and the expression of proinflammatory cytokines (IL-17A and RORγT). Furthermore, expression levels of PD-L1, TGF-β, and PGE2 were significantly upregulated in co-cultured ADSCs relative to those in monocultured ADSCs.

Conclusion

ADSCs ameliorate OVA-induced AD in mice mainly by downregulating IL-17 secretion of Th17 cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02774-7.

Biological agents targeting interleukin-13 for atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is a chronic inflammatory skin disease that is pathogenically driven by type-2 inflammation. Interleukin-13 (IL-13) plays a central role in AD pathogenesis, as confirmed by the clinical efficacy of agents that selectively block IL-13, although their therapeutic value and place-in-therapy are incompletely defined.

AREAS COVERED

The aim of this review article is to describe preclinical and clinical data regarding selective IL-13 inhibitors investigated in AD. In particular, we discuss the clinical outcomes obtained with lebrikizumab and tralokinumab, which are in a more advanced phase of development.

EXPERT OPINION

Biological agents that neutralize IL-13 have demonstrated clinical benefits in treating AD with excellent safety profiles. Robust clinical evidence exists in support of tralokinumab, which underwent phase III trials, met the predefined primary endpoints, and is approaching the market. In contrast, clinical trial testing for lebrikizumab needs to be completed to fully assess its therapeutic potential.

PLAIN LANGUAGE SUMMARY

Atopic dermatitis (AD) is a chronic pathological inflammatory skin disease that results from type-2 inflammation. Selective interleukin-13 (IL-13) inhibitors have shown clinical efficacy against AD, suggesting that IL-13 plays a central in AD pathogenesis. However, the therapeutic value and place-in-therapy of IL-13 inhibitors are incompletely defined. The aim of this review article is to describe preclinical and clinical data for selective IL-13 inhibitors against AD, including lebrikizumab and tralokinumab, which are in a more advanced phase of development. The up-to-date overview of the strengths and limitations of different agents used to treat AD discussed in this article might be useful in driving treatment decision.

Biological medication in atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is a chronic inflammatory skin disorder associated with intense itch/pruritus and skin lesions. Several modalities of treatment including topical therapy, systemic agents, and biologics are available for the treatment of disease. Despite this, management poses challenge due to chronic nature and recurrent episodes in many patients. Biologics represent an important option of treatment for patients who do not respond to the traditional treatment.

AREAS COVERED

In this article, we focused on efficacy and safety of biologics in the treatment of atopic dermatitis. Other therapies are out of the scope of this review. Articles from PubMed and Google scholar and cross references of retrieved articles were used to write the narrative review.

EXPERT OPINION

Biologics play an important role in the treatment of atopic dermatitis. Every biologic has its own place in the treatment considering pharmacological profile, efficacy, and safety. Several biologics have been studied in the treatment of moderate-to-severe cases who failed to provide adequate response to traditional treatment. Dupilumab, is approved for the treatment of moderate-to-severe atopic dermatitis. Tralokinumab and nemolizumab have shown promising results in patients with atopic dermatitis.

The reactome pathway knowledgebase 2022

The Reactome Knowledgebase (https://reactome.org), an Elixir core resource, provides manually curated molecular details across a broad range of physiological and pathological biological processes in humans, including both hereditary and acquired disease processes. The processes are annotated as an ordered network of molecular transformations in a single consistent data model. Reactome thus functions both as a digital archive of manually curated human biological processes and as a tool for discovering functional relationships in data such as gene expression profiles or somatic mutation catalogs from tumor cells. Recent curation work has expanded our annotations of normal and disease-associated signaling processes and of the drugs that target them, in particular infections caused by the SARS-CoV-1 and SARS-CoV-2 coronaviruses and the host response to infection. New tools support better simultaneous analysis of high-throughput data from multiple sources and the placement of understudied ('dark') proteins from analyzed datasets in the context of Reactome's manually curated pathways.

Consensus Update for Systemic Treatment of Atopic Dermatitis

Background

In 2015, the Korean Atopic Dermatitis Association (KADA) working group published consensus guidelines for treating atopic dermatitis (AD).

Objective

We aimed to provide updated consensus recommendations for systemic treatment of AD in South Korea based on recent evidence and experience.

Methods

We compiled a database of references from relevant systematic reviews and guidelines on the systemic management of AD. Evidence for each statement was graded and classified based on thestrength of the recommendation. Forty-two council members from the KADA participated in three rounds of voting to establish a consensus on expert recommendations.

Results

We do not recommend long-term treatment with systemic steroids forpatients with moderate-to-severe AD due to the risk of adverse effects. We recommend treatment with cyclosporine or dupilumab and selective treatment with methotrexate or azathioprine for patients with moderate-to-severe AD. We suggest treatment with antihistamines as an option for alleviating clinical symptoms of AD. We recommend selective treatment with narrowband ultraviolet B for patients with chronic moderate-to-severe AD. We do not recommend treatment with oral antibiotics for patients with moderate-to-severe AD but who have no signs of infection. We did not reach a consensus on recommendations for treatment with allergen-specific immunotherapy, probiotics, evening primrose oil, orvitamin D for patients with moderate-to-severe AD. We also recommend educational interventions and counselling for patients with AD and caregivers to improve the treatment success rate.

Conclusion

We look forward to implementing a new and updated consensus of systemic therapy in controlling patients with moderate-to-severe AD.

Assessment of serum concentrations of matrix metalloproteinase 1, matrix metalloproteinase 2 and tissue inhibitors of metalloproteinases 1 in atopic dermatitis in correlation with disease severity and epidermal barrier parameters

Introduction

Matrix metalloproteinases (MMPs) are a group of proteolytic enzymes, conditioning the integrity of skin cells, however, their role in the inflammatory process of atopic dermatitis (AD) and the direct effect on the epidermal barrier parameters remain unexplained.

Aim

To assess MMP-1, MMP-2, tissue inhibitors of metalloproteinases (TIMP)-1 concentrations in blood serum in the context of transepidermal water loss (TEWL) and stratum corneum hydration in AD. Moreover, serum levels of MMPs and TIMP-1 were analysed in relation to the Eczema Area and Severity Index (EASI).

Material and methods

Forty-three AD patients and 22 control group subjects have been investigated. Serum concentrations of MMP-1, MMP-2, and TIMP-1 have been evaluated with ELISA. TEWL and stratum corneum hydration have been assessed with a TM300 Tewameter and a CM825 Corneometer. Skin lesions in patients with AD have been evaluated with the Eczema Area and Severity Index.

Results

MMP-1 and MMP-2 serum concentrations were significantly higher in the AD group. The results of TIMP-1 serum concentration were similar for both groups. The correlation between the serum concentration and the EASI was demonstrated only for MMP-2 for patients with severe and moderate AD. Patients with AD and TIMP-1 serum concentration greater than MMP-1 presented lower TEWL and higher epidermal hydration.

Conclusions

The results of this study warrant further investigation. The predominance of TIMP-1 over MMP-1 in blood serum can potentially limit TEWL and maintain the proper water content of the epidermis. Future work is necessary to establish how reliable the role of MMP-2 concentration is as an indicator of the severity of AD.

Identification of Immunological Biomarkers of Atopic Dermatitis by Integrated Analysis to Determine Molecular Targets for Diagnosis and Therapy

Purpose

Atopic dermatitis (AD) is a common chronic inflammatory skin disorder associated with immune dysregulation and barrier dysfunction. In this study, we investigated immunological biomarkers for AD diagnosis and treatment using CIBERSORT to identify immune cell infiltration characteristics.

Patients and Methods

Common differentially expressed genes (DEGs) of lesioned (LS) vs non-lesioned (NL) groups were obtained from public datasets (GSE140684 and GSE99802). We performed functional enrichment analysis and selected hub genes from the protein-protein interaction (PPI) network. The hub genes were then subjected to transcription factor (TF), microRNA (miRNA), long non-coding RNA (lncRNA), drug interaction, and protein subcellular localization analyses. We also performed correlation analysis on differentially expressed immune cells, TFs, and hub genes. Receiver operating characteristic (ROC) curve analysis and binomial least absolute shrinkage and selection operator (LASSO) regression analysis were employed to assess the expression of hub genes in the GSE99802, GSE140684, GSE58558, GSE120721, and GSE36842 datasets.

Results

We identified 238 common DEGs and 25 hub genes. Additionally, we predicted TFs, miRNAs, lncRNA, drugs, and protein subcellular localizations. The proportions of activated dendritic cells (DCs) and CD4+ memory T cells were relatively high in the LS skin. Expression levels of the TF FOXC1 were negatively correlated with target genes and the abundance of two immune cell types. The LASSO model showed that GZMB, CXCL1, and CD274 are candidate diagnostic biomarkers.

Conclusion

Our study suggests that downregulated expression of FOXC1 expression may enhance the levels of chemokines, chemokine receptors, T cell receptor signaling molecules, activating CD4+ memory T cells and DCs in AD.

IL-12 regulates type 3 immunity through interfollicular keratinocytes in psoriasiform inflammation

[Figure: see text].

Atopic Dermatitis: From Etiology and History to Treatment

Atopic dermatitis (AD) is a chronic recurrent inflammatory skin disease in patients with atopy. Atopy itself, is defined as a predisposition to develop immune response with overproduction of immunoglobulin E to low doses of allergens. AD is one of the most common skin disorders in the developed world, affecting up to 20% of children and about 3% of adults. The pathogenesis of the disease is complex, with both genetic and environmental factors playing a significant role in it. Clinically, hallmarks of atopic dermatitis include dry, itchy skin and various cutaneous efflorescence, compatible to dermatitis or eczema. Atopic dermatitis subdivides into three morphological variants manifesting during infancy, childhood and adulthood. Various environmental factors and associated diseases may have serious influence on the clinical course or may trigger disease relapses. The aim of this review article is to serve as a comprehensive overview of the etiology, pathogenesis, clinical course and diagnosis, as well as potential challenges facing the successful treatment of atopic dermatitis.

Transcriptomic Profiling of Tape-Strips From Moderate to Severe Atopic Dermatitis Patients Treated With Dupilumab

BACKGROUND

Tape-strips are a minimally invasive approach to characterize skin biomarkers in atopic dermatitis (AD). However, they have not yet been used for tracking gene expression changes with systemic treatment.

OBJECTIVE

The aim of the study was to evaluate gene expression changes and therapeutic response biomarkers in AD patients before and after dupilumab (interleukin 4Rα antibody) treatment using tape-strips to obtain epidermal tissue for analysis.

METHODS

Lesional and nonlesional tape-stripped skin was sampled from 18 AD patients before and after dupilumab treatment and from 17 healthy subjects and analyzed by RNA-seq.

RESULTS

At baseline, we detected 6745 and 4859 differentially expressed genes between lesional and nonlesional skin versus normal, respectively, whereas 841 and 977 genes were differentially expressed after treatment, respectively (fold change >1.5 and false discovery rate <0.05). Tape-strips captured significant modulation with dupilumab in key AD immune (eg, C-C motif chemokine ligand 13 [CCL13], CCL17, CCL18) and barrier (eg, periplakin, FA2H) biomarkers. Changes in biomarkers (CCL20, interleukin 34, FABP7) were also significantly correlated with clinical disease improvements (Eczema Area and Severity Index; R > 0.5 or R < -0.4, P < 0.05).

CONCLUSIONS

This real-life study represents the first comprehensive RNA-seq molecular profiling of tape-strips from moderate to severe AD patients after dupilumab therapy. Analysis of tape strip specimens detected significant gene expression changes in key AD biomarkers with dupilumab treatment, suggesting that this approach may be useful to monitor therapeutic responses in inflammatory skin diseases.

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.

Diversity of T Helper and Regulatory T Cells and Their Contribution to the Pathogenesis of Allergic Diseases

T helper (Th) and regulatory T (Treg) cells represent important effectors of adaptive immunity. They mediate communication between the immune system and tissue sites and thereby coordinate effective defense against environmental threats or maintain tolerance, respectively. Since the discovery of two prototypic T helper cells, Th1 and Th2, additional phenotypic and functional distinct subsets have been described ranging from Th17, Th22, Th9, and T follicular helper cells. The same holds true for regulatory T cells that represent a family with functionally distinct subsets characterized by co-expression of the transcription factors T-bet, Gata3, or RORγt. Here, we summarize the current knowledge on differentiation and function of T helper and regulatory T cell subsets and discuss their lineage stability versus plasticity towards other subsets. In addition, we highlight the direct and indirect contribution of each subset to the pathology of allergies and indicate novel therapies for specific targeting the effector functions of T helper and regulatory T cells.

An integrative network-based approach for drug target indication expansion

BACKGROUND

The identification of a target-indication pair is regarded as the first step in a traditional drug discovery and development process. Significant investment and attrition occur during discovery and development before a molecule is shown to be safe and efficacious for the selected indication and becomes an approved drug. Many drug targets are functionally pleiotropic and might be good targets for multiple indications. Methodologies that leverage years of scientific contributions on drug targets to allow systematic evaluation of other indication opportunities are critical for both patients and drug discovery and development scientists.

METHODS

We introduced a network-based approach to systematically screen and prioritize disease indications for drug targets. The approach fundamentally integrates disease genomics data and protein interaction network. Further, the methodology allows for indication identification by leveraging state-of-art network algorithms to generate and compare the target and disease subnetworks.

RESULTS

We first evaluated the performance of our method on recovering FDA approved indications for 15 randomly selected drug targets. The results showed superior performance when compared with other state-of-art approaches. Using this approach, we predicted novel indications supported by literature evidence for several highly pursued drug targets such as IL12/IL23 combination.

CONCLUSIONS

Our results demonstrated a potential global approach for indication expansion strategies. The proposed methodology enables rapid and systematic evaluation of both individual and combined drug targets for novel indications. Additionally, this approach provides novel insights on expanding the role of genes and pathways for developing therapeutic intervention strategies.

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.

Alternative uses of ustekinumab for non-indicated dermatological conditions: a systematic review

Ustekinumab is approved for the treatment of psoriasis and Crohn's disease. Because many dermatological conditions are due to immune-mediated development, ustekinumab may be effective in other conditions. A systematic review of the off-label uses of ustekinumab, as well as on-label adverse effect, was performed, reporting on clinical improvement. MEDLINE, Embase, Web of Science, and Cochrane databases were searched for studies regarding ustekinumab treatment of rativa (HS), lichen planus (LP), pyoderma gangrenosum (PG), pityriasis rubra pilaris (PRP), cutalopecia areata (AA), atopic dermatitis (AD), Bechet's disease, bullous pemphigoid (BP), hidradenitis suppuaneous sarcoidosis, cutaneous systemic lupus erythematosus (SLE), and vitiligo. Descriptive statistics were performed. 74 articles of 4596 screened were included, and reported on 212 patients receiving ustekinumab treatment. Across all studies, ustekinumab showed promise in treating patients: AA (10/12 patients; 83.3% improvement), AD (28/74 patients; 37.8% improvement), HS (42/52 patients; 80.8% improvement), and PRP (25/27 patients; 92.6% improvement), among others. Adverse events were noted with the use of ustekinumab, including development of AA (four patients), AD (three patients), and BP (four patients), among others. Ustekinumab can be a promising option for patients with dermatological conditions refractory to traditional therapies. Adverse events must be monitored in certain patients.

Immunologic Adverse Effects of Biologics for the Treatment of Atopy

The use of biologic agents as therapies for atopic diseases such as asthma and atopic dermatitis has increased greatly in recent years. The biological agents used to treat atopic diseases are for the most part monoclonal antibodies that suppress the immune response and reduce inflammation by targeting particular cytokines or other molecules involved in Th1, Th2, or Th17 immune reactions. Various side effects and rare complications have been reported from these agents. In this review, we discuss mechanisms of various adverse effects for the biologic agents currently in use or in development for atopic and inflammatory diseases. Monoclonal antibodies targeting the Th1 and Th17 pathways have been associated with significant side effects, partially due to their ability to cause significant impairment in immune responses to pathogens because of the immunologic alterations that they produce. Biologicals targeting Th2-mediated inflammation have had fewer reported side effects, though many are new and emerging drugs whose adverse effects may remain to be fully elucidated with more use. Therefore, continued long-term safety monitoring is required. As with all therapies, the risks associated with side effects of biologics must be balanced against the benefits these drugs offer for treating atopic diseases. One of the most apparent benefits is the steroid-sparing effect of well-chosen biologic therapy used to treat severe atopic disease. In contrast with the quite favorable safety profile of currently available biologics that target the Th2-mediated immune response, chronic systemic corticosteroid use is associated with significant side effects, many of which impact the majority of patients who are placed on long-term steroid therapy.

Current and Future Monoclonal Antibodies in the Treatment of Atopic Dermatitis

Atopic dermatitis is a common immunologic skin disease. Mild atopic dermatitis can be managed with emollients and topical therapies such as low potency topical steroids, which have a favorable safety profile. Severe atopic dermatitis, in contrast, is a challenging disease to treat. Topical therapies are typically inadequate for control of severe atopic dermatitis. When topical therapies fail, the mainstay of therapy for severe atopic dermatitis has traditionally been phototherapy or off-label use of systemic immunosuppressant treatment, yet systemic immunosuppressants all have significant potential toxicities, drug interactions, and contraindications, requiring close monitoring. Targeted biologics are therefore attractive treatment options for topical therapy-refractory cases of atopic dermatitis, with the potential to offer effective, safer treatment of uncontrolled atopic dermatitis. Dupilumab, as the only biologic therapy currently FDA-approved for atopic dermatitis, is effective for many patients, but there is need for continuing study of additional biologic therapies to address the needs of diverse patients with uncontrolled atopic dermatitis.

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.

Cytokine RNA In Situ Hybridization Permits Individualized Molecular Phenotyping in Biopsies of Psoriasis and Atopic Dermatitis

Detection of individual cytokines in routine biopsies from patients with inflammatory skin diseases has the potential to personalize diagnosis and treatment selection, but this approach has been limited by technical feasibility. We evaluate whether a chromogen-based RNA in situ hybridization approach can be used to detect druggable cytokines in psoriasis and atopic dermatitis. A series of psoriasis (n = 20) and atopic dermatitis (n = 26) biopsies were stained using RNA in situ hybridization for IL4, IL12B (IL-12/23 p40), IL13, IL17A, IL17F, IL22, IL23A (IL-23 p19), IL31, and TNF (TNF-α). NOS2 and IFNG, canonical psoriasis biomarkers, were also included. All 20 of the psoriasis cases were positive for IL17A, which tended to be the predominant cytokine, although some cases had relatively higher levels of IL12B, IL17F, or IL23A. The majority of cytokine expression in psoriasis was epidermal. A total of 22 of 26 atopic dermatitis cases were positive for IL13, also at varying levels; a subset of cases had significant IL4, IL22, or IL31 expression. Patterns were validated in independent bulk RNA-sequencing and single-cell RNA-sequencing datasets. Overall, RNA in situ hybridization for cytokines appears highly specific with virtually no background staining and may allow for individualized evaluation of treatment-relevant cytokine targets in biopsies from patients with inflammatory skin disorders.

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.