Delgocitinib ointment, a topical Janus kinase inhibitor, in adult patients with moderate to severe atopic dermatitis: A phase 3, randomized, double-blind, vehicle-controlled study and an open-label, long-term extension study

JAK-STAT signaling in human disease: From genetic syndromes to clinical inhibition

Since its discovery, the Janus kinase-signal transduction and activation of transcription (JAK-STAT) pathway has become recognized as a central mediator of widespread and varied human physiological processes. The field of JAK-STAT biology, particularly its clinical relevance, continues to be shaped by 2 important advances. First, the increased use of genomic sequencing has led to the discovery of novel clinical syndromes caused by mutations in JAK and STAT genes. This has provided insights regarding the consequences of aberrant JAK-STAT signaling for immunity, lymphoproliferation, and malignancy. In addition, since the approval of ruxolitinib and tofacitinib, the therapeutic use of JAK inhibitors (jakinibs) has expanded to include a large spectrum of diseases. Efficacy and safety data from over a decade of clinical studies have provided additional mechanistic insights while improving the care of patients with inflammatory and neoplastic conditions. This review discusses major advances in the field, focusing on updates in genetic diseases and in studies of clinical jakinibs in human disease.

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.

Janus kinase inhibitors for the therapy of atopic dermatitis

The JAK-STAT pathway is involved in the signaling of multiple cytokines driving cutaneous inflammation in atopic dermatitis (AD). Janus kinase (JAK) inhibitors target individual receptor-associated kinases, thereby preventing the mediation of inflammatory signals. Several JAK inhibitors with varying mechanism of action, potency, and safety represent potential therapeutic options for AD in both topical and systemic application. The JAK1/2 selective JAK inhibitor baricitinib was the first substance from this class of drugs approved by the EMA for the systemic oral treatment of AD. The clinical development program of the JAK1 selective inhibitors upadacitinib and abrocitinib is finalized with positive results for AD. The PAN-JAK inhibitor delgocitinib was the first substance being approved for the treatment of AD (in Japan). This review article covers the rising data on investigational and approved JAK inhibitors in the context of the treatment of AD.

Orengedokuto exerts anti-allergic effects via inhibition of effector T cell activation in a murine model of contact hypersensitivity

Orengedokuto (OGT) is a Kampo prescription that has been used for the treatment of inflammation, hypertension, gastrointestinal disorders, and liver and cerebrovascular diseases. It is also used for the treatment of skin diseases such as urticaria and atopic dermatitis. We previously studied its anti-allergic effects of OGT on the murine model of 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) and demonstrated that it significantly suppresses ear swelling in a dose-dependent manner. However, the mechanism underlying this activity remained unknown. Here, we sought to identify the mechanism involved. Using a murine model of TNCB-induced CHS, together with adoptive cell transfer experiments, we found that the anti-allergic effects of OGT may be due to the inhibition of effector T cell activation and not the induction and/or activation of regulatory T cells. Flow cytometry analysis revealed that oral administration of OGT suppressed the increase in CD8⁺CD44^highCD62L⁺ cell number in draining lymph nodes (dLNs) of mice sensitized with 5% TNCB. Additionally, ex vivo experiments confirmed the suppressive effect of OGT on the activation of effector T cells, as interferon-γ (IFN-γ) production by cultured lymphocytes obtained from 5% TNCB-sensitized mice and stimulated with anti-CD3ε and anti-CD28 monoclonal antibodies was reduced by OGT administration. In conclusion, our finding suggests that OGT exerts anti-allergic effects by regulating the activation of effector T cells involved in inflammatory skin diseases such as atopic dermatitis.

Efficacy and safety of topical Janus kinase and phosphodiesterase inhibitor-4 inhibitors for the treatment of atopic dermatitis: A network meta-analysis

Topical Janus kinase (JAK) and phosphodiesterase-4 (PDE4) inhibitors are novel treatment approaches for atopic dermatitis (AD). This study aimed to compare the efficacy and safety of JAK and PDE4 inhibitors for AD treatment. The databases of PubMed, EMBASE, Web of Science, and Cochrane Library were searched until June 2021 for eligible studies of AD patients treated with topical JAK and PDE4 inhibitors. Baseline and follow-up data were extracted. Efficacy of JAK inhibitors was evaluated using Investigator's Global Assessment (IGA) achieving "clear" or "almost clear", with 2 points or more improvement from baseline at the end of treatment, referred to as "IGA response"). A Bayesian multiple treatment network meta-analysis with fixed effects was performed. Odds ratio (OR) with 95% credibility interval (CrI) were used for comparing the efficacy of JAK and PDE4 inhibitors with placebo for AD. A total of 10 randomized controlled trials of topical JAK and PDE4 inhibitors with 4689 patients were included for analysis. A total of three topical JAK inhibitors and two topical PDE4 inhibitors were included. Compared with placebo, all JAK and PDE4 inhibitors had higher IGA response at 4 weeks of treatment. Notably, with similar safety profile, tofacitinib 2% b.i.d., ruxolitinib 1.5% b.i.d., and delgocitinib 3% b.i.d. showed favorable IGA response compared with topical tacrolimus and corticosteroids. Ranking analysis suggested that among all included JAK and PDE4 inhibitors, tofacitinib 2% b.i.d. had the highest probability of achieving IGA response (SUCRA = 0.880). Besides, JAK and PDE4 inhibitors showed non-inferior safety profile with placebo. This study confirmed that topical JAK and PDE4 inhibitors had promising treatment efficacy and safety for AD patients. Tofacitinib 2% b.i.d., ruxolitinib 1.5% b.i.d. and delgocitinib 3% b.i.d. showed superior efficacy over other JAK and PDE4 inhibitors.

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.

Efficacy and Safety of Janus Kinase Inhibitors for the Treatment of Atopic Dermatitis: A Systematic Review and Meta-Analysis

BACKGROUND

Current therapeutic options for atopic dermatitis (AD) are limited. Janus kinase (JAK) inhibitors may be viable alternatives.

OBJECTIVES

To assess the efficacy and safety of JAK inhibitors for AD treatment.

METHODS

We searched PubMed, Embase, the Cochrane Controlled Register of Trials, Web of Science, Global Resource of Eczema Trials database, and ClinicalTrials.gov from inception to September 1, 2020. Randomized clinical trials (RCTs) comparing JAK inhibitors with placebo/vehicle treatment for AD patients were included. The primary study outcomes included (1) the change (%) from the Eczema Area and Severity Index (EASI) baseline expressed as weighted mean difference (WMD) and 95% confidence interval (95% CI), and (2) the Investigator's Global Assessment (IGA) response and safety outcomes expressed as relative risk (RR) and 95% CI.

RESULTS

We included 14 RCTs published in 13 studies (3,822 patients). Treatment with JAK inhibitors significantly improved IGA response (RR 2.83, 95% CI 2.25-3.56, p < 0.001) and EASI score (WMD -28.82, 95% CI -34.48 to -23.16, p < 0.001). JAK inhibitor treatment achieved the largest improvement in both IGA response (RR 3.59, 95% CI 2.66-4.84, p < 0.001) and EASI score (WMD -42.00, 95% CI -48.64 to -35.36, p < 0.001) by week 4 of treatment. Topical JAK inhibitors were significantly more efficacious than oral inhibitors. Upadacitinib treatment for 4 weeks was most effective in reducing EASI score (WMD -53.92, 95% CI -69.26 to -38.58, p < 0.001), while abrocitinib for 4 weeks led to the most effective IGA response (RR 5.47, 95% CI 2.74-10.93, p < 0.001). There was no difference in the frequency of adverse events (AEs) leading to discontinuation; however, JAK inhibitors use, especially abrocitinib, led to a higher incidence of treatment-emergent AEs (RR 1.25, 95% CI 1.10-1.42, p = 0.001).

CONCLUSION

Our results imply that JAK inhibitors are an effective and safe AD treatment. Nevertheless, further trials with longer duration and head-to-head comparisons of different JAK inhibitors are needed.

JAK inhibitors in the treatment of atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disorder associated with heterogenous presentation and often immense patient burden. Safe, targeted treatment options are currently limited. This focused review of the published literature, including clinical trial results, case reports, and abstracts, as well as presentations from scientific meetings and data from industry press releases, describes the use of topical and systemic Janus kinase (JAK) inhibitors in the treatment of AD. New topical JAK inhibitors include ruxolitinib (JAK1/2) and delgocitinib (pan-JAK). Ruxolitinib cream met all primary and secondary endpoints in phase 3 clinical trials for mild-to-moderate AD with minimal treatment-emergent adverse events. Delgocitinib ointment was recently approved in Japan for pediatric and adult AD. Oral JAK inhibitors include baricitinib (JAK1/2), abrocitinib (JAK1-selective), and upadacitinib (JAK1-selective). All 3 met primary and secondary endpoints across numerous trials for moderate-to-severe AD. Treatment-emergent adverse events were mainly mild to moderate and included acne, nausea, headache, upper respiratory tract infection, and to a lesser degree, herpes infection and selected laboratory abnormalities. JAK inhibitors hold great promise as the next generation of targeted AD therapy. While their outstanding efficacy is balanced by a favorable safety profile in clinical trials, real-world data are needed to better understand long-term safety, durability, and treatment success.

Safety of Janus kinase (JAK) inhibitors in the short-term treatment of atopic dermatitis

Atopic dermatitis (AD) is a chronic heterogeneous condition characterized by erythematous, pruritic, and inflamed skin. Janus kinase (JAK) inhibitors are a new class of drugs that target proteins in the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. These drugs can be administered orally or topically to inhibit signaling of the JAK-STAT pathway and minimize the production of proinflammatory cytokines. The efficacy and safety of JAK inhibitors have been investigated in phase 2 and 3 clinical trials for AD. The safety of new medications, which are immunosuppressive by nature, is of utmost concern for the prescriber and patient alike. Herein we summarize the safety results of clinical trials using oral abrocitinib, upadacitinib, and baricitinib, as well as topical ruxolitinib and delgocitinib for the treatment of AD. The most prevalent (2-5% occurrence rate) treatment-emergent adverse events from oral JAK inhibitor use in AD were nausea, upper respiratory tract infection, headache, herpes zoster, herpes simplex, acne, increased blood creatine phosphokinase levels, and decreased platelet counts. Topical JAK inhibitors were not associated with systemic effects. All studies reported that JAK inhibitors were well tolerated in patients with AD in comparison with the control group. While the use of JAK inhibitors in patients suffering from AD is very promising, trials reported to date are of short duration (maximum 16 weeks), and more information on the long-term safety of these novel agents is required.

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.

Current Clinical Options for the Management of Itch in Atopic Dermatitis

Pruritus is the most burdensome and prevalent symptom in patients suffering from atopic dermatitis. Treating atopic itch has historically been a challenge due to multiple underlying mechanisms within its pathogenesis and an incomplete understanding of them. In recent years, our understanding of these mechanisms have increased tremendously and subsequently, new treatments have reached the market that target the pathophysiology of atopic itch from different angles. In addition, there are several promising new treatments currently in development and trials. In the current article, we discuss these currently available treatment options, their available evidence and efficacy, and highlight some of the more recent advancements in the field.

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.

Novel therapies and the potential for a personalized approach to atopic dermatitis

PURPOSE OF REVIEW

To provide a cutting-edge overview of recent developments in topical and systemic therapeutic approaches for the treatment of atopic dermatitis (AD).

RECENT FINDINGS

Growing knowledge about key pathways in AD and stratification of patient's subgroups have set the basis for a new era of targeted topical and systemic therapy in AD.Different aspects have to be considered in the decision process for topical versus systemic therapy. Further on, co-factors from the patient's side as well as the side of the substances determine the choice of a particular drug/drug type.Tailored medicine in AD treatment comprises drugs of the group of small molecules such as topical Janus kinases-signal transducer and activator of transcription (JAK-STAT) inhibitors or phosphodiesterase 4 inhibitors, and JAK-STAT inhibitors for oral use, as well as monoclonal antibodies for subcutaneous use, which target key cytokines or cytokine receptors in AD pathogenesis.

SUMMARY

The current stepwise treatment approaches, which are settled on basic therapy and structured patient education and gradually expanded depending on the severity of the disease by stronger topical or even systemic measures, will have to be adapted to the rapid development in the therapeutic field, mirrored by an impressive high number of ongoing clinical studies as well as novel drugs at late stages of clinical trials with so far quite promising results.

The efficacy and safety of JAK inhibitors for atopic dermatitis: a systematic review and meta-analysis

BACKGROUND

Atopic dermatitis (AD) is one of the serious global problems. There were wide concerns about whether Janus kinase (JAK) inhibitor was an alternative treatment for AD.

METHOD

Eight databases were searched from the earliest publication date available to January 2, 2021. We included randomized controlled trials comparing JAK inhibitors with control treatment for AD. Data were pooled using Stata.14 software and performed as mean differences (MD) and risk ratios (RR) with 95% CIs. We did subgroup analysis based on specific outcomes.

RESULTS

A total of studies, ten randomized controlled trials, with 2583 patients were included in the final synthesis. This meta-analysis showed JAK inhibitor resulted in significant improvement on EASI total score (MD = -0.31; 95%CI, -0.46 to -0.17; p = .000; I² = 90.0%, p = .000) and pruritus numerical rating scale (NRS) score (MD = -1.15; 95%CI, -1.48 to -0.83; p = .000; I² = 95.9%, p = .000), without the higher risk of total adverse effects (RR = 1.02; 95%CI, 0.90-1.16; p = .745; I² =27.9%, p = .206).

CONCLUSIONS

JAK inhibitor was a promising option for atopic dermatitis. More data and surveillance will be needed to identify efficacy, safety, and the risk of adverse effects.

The IL-4, IL-13 and IL-31 pathways in atopic dermatitis

Introduction: Atopic dermatitis (AD) is the most common inflammatory skin disease. It has a complex pathophysiology, with a combination of immune dysregulation and intrinsic barrier defects driving cutaneous inflammation and allergic symptomatology. The IL-4, IL-13 and IL-31 inflammatory pathways have been identified as hallmark features in the pathogenesis of the disease, contributing uniquely and synergistically to immune and barrier abnormalities as well as the key symptoms, such as pruritis. Novel therapeutics that target these pathways have been under development to find treatments for AD.Areas covered: This review discusses the IL-4, IL-13 and IL-31 pathways in AD. We will also detail novel targeted therapeutics that have recently been or are currently in clinical trials for AD. A literature search was conducted by querying Scopus, Google Scholar, PubMed, and Clinicaltrials.gov up to January 2021 using combinations of the search terms 'IL-4' 'IL-13' 'IL-31' 'atopic dermatitis' 'immune pathway' 'biologics' 'novel therapeutics' 'JAK/STAT inhibitors.'Expert opinion: The complex pathophysiology of AD advocates for innovation. Novel minimally invasive sampling modalities such as tape stripping will allow for a broader characterization of the immunomechanisms behind AD pathophysiology. This will allow for the continued development of a personalized medicine approach to treat 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.

Interferon-γ downregulates tight junction function, which is rescued by interleukin-17A

Although atopic dermatitis (AD) has been reported to be a typical type 2 immune response disease, it is also an inflammatory skin disease that involves cytokines, such as Th1, Th17 and Th22. However, little is known about the mechanism by which the candidate cytokines, alone or in combination, are involved in AD pathology. Differences in cytokine balance, which contribute to the complexity of AD pathology, may influence the stratum corneum barrier function through tight junction (TJ) functional stability and contribute to disease severity. To confirm the regulatory mechanism of TJ protein expression in AD, we investigated the Th1 and Th17 pathways, which are the initiation factors of chronic AD pathology. We examined the effects of these cytokines on TJ protein expression in normal human epidermal keratinocytes in vitro, and also examined their function in a human skin equivalent model. We observed a time‐ and dose‐dependent inhibitory effect of IFN‐γ on claudin‐1 expression via the IFN‐γ receptor/JAK/STAT signalling pathway. IFN‐γ impaired TJ function in a human skin equivalent model. Moreover, we investigated co‐stimulation with IL‐17A, which is highly expressed in AD skin lesions and found that IL‐17A restores IFN‐γ‐induced TJ dysfunction. This restoration of TJ function was mediated by atypical protein kinase C zeta activation without recovery of TJ protein expression. These results are informative for personalized AD treatment via systemic therapies using anti‐cytokine antibodies and/or JAK inhibitors.

Delgocitinib ointment in pediatric patients with atopic dermatitis: A phase 3, randomized, double-blind, vehicle-controlled study and a subsequent open-label, long-term study

BACKGROUND

Delgocitinib 0.5% ointment, a topical Janus kinase inhibitor, has been approved in Japan for adult patients with atopic dermatitis (AD).

OBJECTIVE

To evaluate the efficacy and safety of delgocitinib ointment in pediatric patients with AD.

METHODS

Part 1 of this study was a 4-week double-blind period in which Japanese patients aged 2 through 15 years were randomized in a 1:1 ratio to delgocitinib 0.25% ointment or vehicle ointment. Part 2 was a 52-week extension period. Eligible patients entered part 2 to receive 0.25% or 0.5% delgocitinib ointment.

RESULTS

At the initiation of the study, approximately half of the patients had moderate AD. At the end of treatment in part 1, the least-squares mean percent change from baseline in modified Eczema Area and Severity Index score, the primary efficacy endpoint, was significantly greater for delgocitinib ointment than for vehicle (-39.3% vs +10.9%, P < .001). In part 2, improvements in AD were also seen through week 56. Most adverse events were mild and unrelated to delgocitinib across the study periods.

LIMITATIONS

Only Japanese patients were included. In part 2, no control group was included and rescue therapy was allowed.

CONCLUSION

Delgocitinib ointment was effective and well tolerated when applied to Japanese pediatric patients with AD for up to 56 weeks.

New Treatments for Atopic Dermatitis Targeting Skin Barrier Repair via the Regulation of FLG Expression

Atopic dermatitis (AD) is one of the most common chronic, inflammatory skin disorders with a complex etiology and a broad spectrum of clinical phenotypes. Despite its high prevalence and effect on the quality of life, safe and effective systemic therapies approved for long-term management of AD are limited. A better understanding of the pathogenesis of atopic dermatitis in recent years has contributed to the development of new therapeutic approaches that target specific pathophysiological pathways. Skin barrier dysfunction and immunological abnormalities are critical in the pathogenesis of AD. Recently, the importance of the downregulation of epidermal differentiation complex (EDC) molecules caused by external and internal stimuli has been extensively emphasized. The purpose of this review is to discuss the innovations in the therapy of atopic dermatitis, including biologics, small molecule therapies, and other drugs by highlighting regulatory mechanisms of skin barrier-related molecules, such as filaggrin (FLG) as a crucial pathway implicated in AD pathogenesis.

Janus Kinase Inhibitors in Dermatology: Part 2: Applications in Psoriasis, Atopic Dermatitis, and Other Dermatoses

Dermatologists' interest in the Janus-associated kinase (JAK)/signal transducers and activators of transcription (STAT) pathway has been growing as evidence builds to support its key role in the pathogenesis of inflammatory skin diseases. Because certain proinflammatory cytokines use the JAK/STAT pathway for signal transduction, it has become a promising therapeutic target in diseases where selective modulation of the immune system can be useful. We aim to review current knowledge of the JAK/STAT signaling pathway and its role in immune-mediated skin diseases. In the second part of the review we cover the efficacy and safety of oral and topical JAK inhibitors in the treatment of psoriasis, atopic dermatitis, and other skin diseases.

Practical algorithm to inform clinical decision-making in the topical treatment of atopic dermatitis

Atopic dermatitis is a chronic relapsing, inflammatory skin disorder associated with skin barrier dysfunction, the prevalence of which has increased dramatically in developing countries. In this article, we propose a treatment algorithm for patients with mild-to-moderate and severe atopic dermatitis flares in daily clinical practice. An international panel of 15 dermatology and allergy experts from eight countries was formed to develop a practical algorithm for the treatment of patients with atopic dermatitis, with a particular focus on topical therapies. In cases of mild-to-moderate atopic dermatitis involving sensitive skin areas, the topical calcineurin inhibitor pimecrolimus should be applied twice daily at the first signs of atopic dermatitis. For other body locations, patients should apply a topical calcineurin inhibitor, either pimecrolimus or tacrolimus, twice daily at the first signs of atopic dermatitis, such as pruritus, or twice weekly in previously affected skin areas. Emollients should be used regularly. Patients experiencing acute atopic dermatitis flares in sensitive skin areas should apply a topical corticosteroid twice daily or alternate once-daily topical corticosteroid/topical calcineurin inhibitor until symptoms improve. Following improvement, topical corticosteroid therapy should be discontinued and patients switched to a topical calcineurin inhibitor. Maintenance therapy should include the use of pimecrolimus once daily for sensitive areas and tacrolimus for other body locations. This treatment algorithm can help guide clinical decision-making in the treatment of atopic dermatitis.

Itch and Sleep Improvements with Baricitinib in Patients with Atopic Dermatitis: A Post Hoc Analysis of 3 Phase 3 Studies

Introduction

Burdensome symptoms of atopic dermatitis include itch and sleep disturbance. This post hoc analysis reports the effect of baricitinib on itch and sleep disturbance during the first week of treatment in 3 phase 3 studies.

Methods

Patients were randomized 2:1:1:1 to once-daily placebo or baricitinib 1 mg, 2 mg, or 4 mg in the BREEZE-AD1 and -AD2 studies and 1:1:1 to once-daily placebo or baricitinib 2 mg or 4 mg in the BREEZE-AD7 study. Topical corticosteroids were only allowed in BREEZE-AD7. Patients completed the itch numerical rating scale and atopic dermatitis sleep scale (ADSS) items 1–3 using an electronic daily diary. Data were analyzed by study as least squares mean percent change from baseline in daily scores for the randomized patients. Mixed model repeated measures analysis was used to analyze change from baseline values.

Results

A total of 624, 615, and 329 patients were randomized in BREEZE-AD1, -AD2, and -AD7, respectively. Itch severity significantly improved with baricitinib 2 mg and 4 mg versus placebo starting at day 2 (1 day after first dose) in BREEZE-AD1 and -AD7 and at day 1 in BREEZE-AD2. Patients’ ability to fall asleep (ADSS item 1) significantly improved with baricitinib 2 mg and 4 mg versus placebo starting at day 2 in all three studies. There were significant improvements in patients waking due to itch (ADSS item 2) with baricitinib 4 mg versus placebo starting at day 2 in all three studies. Patients’ ability to return to sleep after being woken by itch (ADSS item 3) was significantly improved with baricitinib 4 mg versus placebo starting at day 2 in BREEZE-AD1 and -AD2 and at day 4 in BREEZE-AD7.

Conclusion

Rapid onset of action, typically 1 day after taking the first dose of baricitinib, was observed consistently for the burdensome symptoms of itch and sleep disturbance.

ClinicalTrials.gov identifiers

BREEZE-AD1, NCT03334396; BREEZE-AD2, NCT03334422; BREEZE-AD7, NCT03733301.

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.

Application of Janus Kinase Inhibitors in Atopic Dermatitis: An Updated Systematic Review and Meta-Analysis of Clinical Trials

Janus kinase (JAK) inhibitors are promising treatments for atopic dermatitis (AD). The aim of this study was to assess the efficacy and safety of JAK inhibitors for AD treatment via the “Grading of Recommendations Assessment, Development, and Evaluation” approach. We identified 15 randomized controlled trials comparing oral or topical JAK inhibitors against placebo to treat AD. A random-effects meta-analysis was performed, and the numbers-needed-to-treat (NNTs)/numbers-needed-to-harm (NNHs) were calculated. Patients treated with JAK inhibitors were associated with higher rates of achieving eczema area and severity index-75 (rate ratio (RR): 2.84; 95% confidence interval (CI): 2.20–3.67; I²: 38.9%; NNT = 3.97), Investigator’s Global Assessment response (RR: 2.99; 95% CI: 2.26–3.95; I²: 0%; NNT = 5.72), and pruritus numerical rating scale response (RR: 2.52; 95% CI: 1.90–3.35; I²: 39.4%; NNT = 4.91) than those treated with placebo. Moreover, patients treated with JAK inhibitors had a higher risk of treatment-emergent adverse events (RR: 1.14; 95% CI: 1.02–1.28; I²: 52%; NNH = 14.80) but not adverse events leading to drug discontinuation. According to the evidence-based results, JAK inhibitors are potentially effective strategies (certainty of evidence: “moderate”) for treating AD with tolerable side effects (certainty of evidence: “low”). Nevertheless, long-term follow-up is required.

Therapeutic New Era for Atopic Dermatitis: Part 2. Small Molecules

Atopic dermatitis (AD) is a chronic, inflammatory cutaneous disease driven by immune dysregulation and skin barrier dysfunction. Currently, we are 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. In contrast to biologics, small molecules are similar to conventional pharmacologic chemical agents used as drugs and are generally prepared by chemical synthesis. Unlike biologics, these drugs often are taken orally or formulated for topical use. The purpose of this review is to summarize the efficacy and safety of the current topical and systemic new therapies in AD by reviewing recently published papers on therapies currently in phase 2 or 3 clinical trials. In this review, it is important to note the characteristics of the study population, the primary endpoints, and whether or not there was concomitant topical therapy allowed. These study design elements may significantly alter the results of studies and should be taken into account. Targeted therapy help push AD treatment into a new era of personalized medicine.

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.

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.

Janus Kinase Inhibitors in Dermatology: Part 2: Applications in Psoriasis, Atopic Dermatitis, and Other Dermatoses

Dermatologists' interest in the Janus-associated kinase (JAK)/signal transducers and activators of transcription (STAT) pathway has been growing as evidence builds to support its key role in the pathogenesis of inflammatory skin diseases. Because certain proinflammatory cytokines use the JAK/STAT pathway for signal transduction, it has become a promising therapeutic target in diseases where selective modulation of the immune system can be useful. We aim to review current knowledge of the JAK/STAT signaling pathway and its role in immune-mediated skin diseases. In the second part of the review we cover the efficacy and safety of oral and topical JAK inhibitors in the treatment of psoriasis, atopic dermatitis, and other skin diseases.

IL-13 antagonists in the treatment of atopic dermatitis

Atopic dermatitis (AD) is a prevalent inflammatory skin disease. IL-13 contributes significantly to the pathogenesis of AD in several ways, and beneficial results have been demonstrated with anti-IL-13 therapies. Currently, the only monoclonal antibody (mAb) approved for AD treatment is dupilumab, an antagonist of the IL-4 receptor alpha (IL-4Rα) subunit common to IL-4 and IL-13 receptors, but clinical trials evaluating anti-IL-13 mAbs are providing promising results. The topics of this review will be mAbs targeting IL-13 for the treatment of AD such as dupilumab, tralokinumab and lebrikizumab, small molecules targeting the IL-13 pathway, and a brief explanation of therapies targeting IL-13 for the treatment of other skin diseases.

Current treatments for atopic dermatitis in Japan

The goal of a treatment regimen for atopic dermatitis is to reach and maintain a state where the patient exhibits mild symptoms or an absence of symptoms, and the patient should not experience disturbance during daily activities. The basis of a treatment regimen for atopic dermatitis is topical therapy, and currently there exist topical corticosteroids, tacrolimus and delgocitinib. Using these, proactive therapy is performed as maintenance therapy after remission induction therapy. However, in cases of moderate to severe atopic dermatitis, topical drugs alone cannot induce remission and systemic therapies such as cyclosporin, ultraviolet therapy, and dupilumab should be used in combination. In particular, dupilumab has many advantages such as high efficacy, relatively few adverse reactions, and ease of use in elderly patients with severe atopic dermatitis. In this review, we present a treatment algorithm for atopic dermatitis that emphasizes the importance of maintaining remission after induction of remission, and summarizes the characteristics of current medication therapy for atopic dermatitis in Japan.

Delgocitinib: First Approval

Delgocitinib, a janus kinase (JAK) inhibitor, is being developed by Japan Tobacco for the treatment of autoimmune disorders and hypersensitivity, including inflammatory skin conditions. The JAK family of tyrosine kinases plays an important role in mediating the biological effects of several inflammatory cytokines, e.g. IL-4, IL-13 and IL-31, which are elevated in patients with atopic dermatitis. Delgocitinib inhibits all members of the JAK family [JAK1, JAK2, JAK3 and tyrosine kinase 2]. Topical delgocitinib (Corectim^®) is approved in Japan for the treatment of atopic dermatitis. This article summarizes the milestones in the development of delgocitinib leading to this first approval for the treatment of adults with atopic dermatitis. Clinical development of the topical formulation is also underway for alopecia areata, chronic hand eczema, discoid lupus erythematosus, inverse psoriasis and atopic dermatitis in several countries worldwide. Clinical development of an oral formulation of delgocitinib is also underway in Japan for the treatment of autoimmune disorders and hypersensitivity.

Pathophysiology and Treatment of Pruritus in Elderly

Pruritus is a relatively common symptom that anyone can experience at any point in their life and is more common in the elderly. Pruritus in elderly can be defined as chronic pruritus in a person over 65 years old. The pathophysiology of pruritus in elderly is still unclear, and the quality of life is reduced. Generally, itch can be clinically classified into six types: Itch caused by systemic diseases, itch caused by skin diseases, neuropathic pruritus, psychogenic pruritus, pruritus with multiple factors, and from unknown causes. Senile pruritus can be defined as a chronic pruritus of unknown origin in elderly people. Various neuronal mediators, signaling mechanisms at neuronal terminals, central and peripheral neurotransmission pathways, and neuronal sensitizations are included in the processes causing itch. A variety of therapies are used and several novel drugs are being developed to relieve itch, including systemic and topical treatments.

IL-24 Negatively Regulates Keratinocyte Differentiation Induced by Tapinarof, an Aryl Hydrocarbon Receptor Modulator: Implication in the Treatment of Atopic Dermatitis

Skin barrier dysfunction, including reduced filaggrin (FLG) and loricrin (LOR) expression, plays a critical role in atopic dermatitis (AD) development. Since aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, mediates keratinocyte differentiation, it is a potential target for AD treatment. Recently, clinical studies have shown that tapinarof, an AHR modulator, attenuated the development of AD. To examine the molecular mechanism involved in this, we analyzed tapinarof-treated normal human epidermal keratinocytes (NHEKs). Tapinarof upregulated FLG and LOR mRNA and protein expression in an AHR-dependent manner. Tapinarof also induced the secretion of IL-24, a cytokine that activates Janus kinase (JAK)-signal transducer and activator of transcription (STAT), leading to the downregulation of FLG and LOR expression. Knockdown of either IL-24 or STAT3 expression by small interfering RNA (siRNA) transfection augmented the upregulation of FLG and LOR expression induced by tapinarof, suggesting that inhibition of the IL-24/STAT3 axis during AHR activation supports the improvement of skin barrier dysfunction. Furthermore, tapinarof alone could restore the downregulation of FLG and LOR expression induced by IL-4, a key cytokine of AD, and its combination with JAK inhibitors enhanced this effect. These findings provide a new strategy for treating AD using AHR modulators and JAK inhibitors.

Regulation of Skin Barrier Function via Competition between AHR Axis versus IL-13/IL-4‒JAK‒STAT6/STAT3 Axis: Pathogenic and Therapeutic Implications in Atopic Dermatitis

Atopic dermatitis (AD) is characterized by skin inflammation, barrier dysfunction, and chronic pruritus. As the anti-interleukin-4 (IL-4) receptor α antibody dupilumab improves all three cardinal features of AD, the type 2 cytokines IL-4 and especially IL-13 have been indicated to have pathogenic significance in AD. Accumulating evidence has shown that the skin barrier function is regulated via competition between the aryl hydrocarbon receptor (AHR) axis (up-regulation of barrier) and the IL-13/IL-4‒JAK‒STAT6/STAT3 axis (down-regulation of barrier). This latter axis also induces oxidative stress, which exacerbates inflammation. Conventional and recently developed agents for treating AD such as steroid, calcineurin inhibitors, cyclosporine, dupilumab, and JAK inhibitors inhibit the IL-13/IL-4‒JAK‒STAT6/STAT3 axis, while older remedies such as coal tar and glyteer are antioxidative AHR agonists. In this article, I summarize the pathogenic and therapeutic implications of the IL-13/IL-4‒JAK‒STAT6/STAT3 axis and the AHR axis in AD.

Emerging Role of Janus Kinase Inhibitors for the Treatment of Atopic Dermatitis

BACKGROUND

Atopic dermatitis (AD) is a common chronic, inflammatory skin condition. The pathogenesis of AD involves many cytokines that utilize the Janus kinase/signal transducer and activator of transcription (JAK-STAT) signaling cascade; therefore, JAK inhibitors may be used in the treatment of AD. This review aims to evaluate the pathophysiology, efficacy, and safety of JAK inhibitors and their emerging role as a therapeutic option for patients with AD.

METHODS

A PubMed search of Phase I, II, and III clinical trials was conducted for relevant literature published between January 2015 and June 2020 utilizing the key terms: JAK inhibitors, atopic dermatitis, efficacy, safety, and treatment. The search was subsequently expanded to include additional terms.

RESULTS

In multiple Phase II and III clinical trials, JAK inhibitors were more efficacious than placebo or vehicle controls and slightly more efficacious in direct comparisons to corticosteroids. Overall, JAK inhibitors have a moderate safety profile for use in AD. Some of the more severe theoretical adverse events included thrombosis and reactivation of viral infections. While data remain limited for the long-term efficacy and safety of JAK inhibitor use in patients with AD, many ongoing clinical trials have promising preliminary results.

DISCUSSION

Short-term data suggest that both topical and oral JAK inhibitors are efficacious and safe for use in patients with AD, although cases of thrombosis and viral disease have been reported. While the current standard treatments for AD are likely preferred, failed therapy with these agents or corticosteroid phobia may be indications for the use of JAK inhibitors in patients with AD.

Biological drugs in the treatment of atopic dermatitis - current recommendations of the Polish Dermatological Society, the Polish Society of Allergology, the Polish Pediatric Society and the Polish Society of Family Medicine

Atopic dermatitis (AD) is secondary to genetic, immunological and microbiological disorders as well as epidermal barrier defects, which are the main targets of therapy. The disease proceeds with periodic exacerbations. Its development and course are influenced by numerous environmental and individual factors. In recent decades, in industrialized countries, there has been a threefold increase in the incidence of AD. There is also an increasing number of cases resistant to topical treatment. Effective treatment of AD should provide control of clinical symptoms, prevent exacerbations and improve the quality of life of patients. The multifactorial etiopathogenesis and various endotypes and phenotypes of AD justify the tendency to optimize and personalize the therapy. Currently, we recommend the use of dupilumab for the treatment of patients from 12 years of age with moderate and severe atopic dermatitis, who do not respond to topical treatment.

JAK-STAT Inhibitors in Atopic Dermatitis from Pathogenesis to Clinical Trials Results

A common disease worldwide is known as atopic dermatitis (AD), named also as atopic eczema, which is a chronic recurrent complex inflammatory skin disorder. It affects 2–10% of the adult population and up to 20% of the pediatric population. The clinical AD picture appears in typically localized eczema and dry skin, and is dominated by a persistent pruritus followed by sleep disturbances. AD strongly impacts on the quality of life of AD patients and their families as well as on social and economic aspects. The pathogenesis of the disease is complex and consists of multiple interactions between immunological disturbances, skin barrier defect, and microbial dysbiosis with environmental influences. The treatment of AD reflects the pathogenetic disorders, starting from basic emollient therapy, and goes to topical anti-inflammatory regimens followed by phototherapy, systemic immunosuppressive drugs, and new biologic immunomodulators. This paper will thus summarize the novel collection of biological treatment JAK-STAT inhibitors dedicated to AD.

Emerging Therapeutic Options for Chronic Pruritus

Chronic pruritus, defined as an unpleasant sensation resulting in a need to scratch that lasts more than 6 weeks, is a prevalent and bothersome symptom associated with both cutaneous and systemic conditions. Due to complex pathogenesis and profuse contributing factors, chronic pruritus therapy remains challenging. Regardless of the well-established antipruritic properties of classic pharmacotherapy (topical therapy, phototherapy and systemic therapy), these methods often provide insufficient relief for affected individuals. Owing to the growing interest in the field of pruritic research, further experimental and clinical data have emerged, continuously supporting the possibility of instigating novel therapeutic measures. This review covers the most relevant current modalities remaining under investigation that possess promising perspectives of approval in the near future, especially opioidergic drugs (mu-opioid antagonists and kappa-opioid agonists), neurokinin-1 receptor antagonists, biologic drugs, Janus kinase inhibitors, ileal bile acid transporter inhibitors, aryl hydrocarbon receptor agonists and histamine H₄ receptor antagonists.

New treatments in atopic dermatitis

OBJECTIVE

To discuss the efficacy and safety of novel and emerging topical and systemic therapeutic agents for atopic dermatitis (AD).

DATA SOURCES

The review of the published literature was performed using the PubMed database, published abstracts and virtual presentations from scientific meetings, posted results on ClinicalTrials.gov, and data from industry press releases.

STUDY SELECTIONS

Primary manuscripts with trial results, case reports, case series, clinical trial data from ClinicalTrials.gov, and articles highlighting expert perspectives on management of AD were selected.

RESULTS

Emerging topical and systemic therapies primarily target the type 2 immune pathway. Moreover, 2 newer targeted medications are now approved by the Food and Drug Administration for both children and adults, crisaborole 2% ointment and dupilumab, with several others in the therapeutic pipeline. New directions in developing topical medications include Janus kinase inhibitors, tapinarof (an aryl hydrocarbon receptor agonist), and agents to correct microbial dysbiosis. In addition to the subcutaneously injected monoclonal antibody targeting the interleukin (IL) 4 receptor (dupilumab), other biologics targeting IL-13, IL-31, IL-33, OX40, and thymic stromal lymphopoietin are currently being tested. Oral Janus kinase inhibitors are showing outstanding efficacy and no serious safety signs, but safety concerns remain.

CONCLUSION

Given the tremendous burden of AD on physical, mental, and social health, the need is high to develop new, targeted therapies. Advances in our understanding of AD pathogenesis have paved the way toward the development of new therapies that promise to revolutionize our management of AD. Future research will focus on long-term efficacy and safety and creating predictive models for choosing best management options on a personalized basis.

Emerging drugs for the treatment of chronic pruritic diseases

INTRODUCTION

Chronic pruritus is non-histaminergic and mediated through a complex interplay of peripheral and central immune and neural pathways. Significant developments in the understanding of chronic pruritus have emerged and paved the way for new, emerging therapies.

AREAS COVERED

This review details the emerging drug landscape for chronic pruritus treatment, focusing on monoclonal antibody agents that target key cytokines and their receptors as well as small molecule agents that inhibit mediators of the immune and neural pathways. The article provides background regarding the currently available therapies and the rationale for the development of new agents based on the current market and recent scientific developments.

EXPERT OPINION

Identification of new targets along neuroimmune itch pathways has allowed for the development of targeted drugs which can be utilized for effective therapy. As we enter a new era of chronic itch treatments, we face exciting prospects and challenges.

Atopic dermatitis

Atopic dermatitis is a common inflammatory skin disorder characterised by recurrent eczematous lesions and intense itch. 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 from skin disease. Atopic dermatitis is associated with increased risk of multiple comorbidities, including food allergy, 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. Currently, there is no cure, but increasing numbers of innovative and targeted therapies hold promise for achieving disease control, including in patients with recalcitrant disease. We summarise and discuss advances in our understanding of the disease and their implications for prevention, management, and future research.