Crisaborole and atopic dermatitis skin biomarkers: An intrapatient randomized trial

Efficacy and safety of Ruxolitinib, Crisaborole, and Tapinarof for mild-to-moderate atopic dermatitis: a Bayesian network analysis of RCTs

Given the lack of head-to-head studies of novel non-steroidal molecule topical therapies in mild-to-moderate atopic dermatitis (AD), network meta-analyses (NMAs) can provide comparative efficacy and safety data for clinical decision-making. In this NMA, we performed a literature search until 01 March 2023 for eligible studies written in English using databases, including PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov. Only double-blind randomized clinical trials (RCTs) with topical Ruxolitinib, Crisaborole, or Tapinarof versus vehicle for patients with mild-to-moderate AD were included. Baseline and follow-up data were extracted. Efficacy 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 success." For binary outcomes, we analyzed in random-effects Bayesian NMA consistency models to compare the efficacy of these 3 topical therapies by odds ratio (OR) with 95% credibility interval (CrI). Overall, 10 phase 2 or phase 3 RCTs were identified, which included 4010 patients with mild to moderate AD. Compared with the topical vehicle control, all these 3 treatments had higher response rate of "IGA success" at the end of trial (Ruxolitinib 1.5% b.i.d: OR, 11.94; 95%CrI, 6.28-23.15; Crisaborole 2% b.i.d: OR, 2.08; 95%CrI, 1.46-3.52; Tapinarof 1% b.i.d: OR, 2.64; 95%CrI, 0.75-9.70). Notably, Ruxolitinib 1.5% b.i.d. had the highest probability of achieving "IGA success" in ranking analysis (Rank 1, SUCRA = 0.75) and lower risk of AE (Rank 8, SUCRA = 0.22). Besides, there was no difference in treatment-related adverse events between 3 therapies. Heterogeneity was not significant across studies.

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.

Atopic dermatitis: treatment and innovations in immunotherapy

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by itching and skin barrier dysfunction. Moderate to severe AD is often refractory to first-line topical treatments, and systemic immunosuppressants have been shown to be effective but have significant adverse effects. The paucity of basic treatments has contributed to the development of targeted topical and systemic immunotherapies based on the use of small molecules and biologic drugs which can directly interact with AD pathogenetic pathways. They represent a new era of therapeutic innovation. Additional new treatments are desirable since AD is a heterogeneous disease marked by different immunological phenotypes. This manuscript will review the mechanism of action, safety profile, and efficacy of promising new systemic immunological treatments for AD. Since moderate to severe AD can result in poor quality of life, the development of targeted and well-tolerated immunomodulators is a crucial purpose. The introduction of new pharmacological agents may offer new therapeutic options. However, there is the need to evaluate how "narrow-acting" agents, such as individual interleukin inhibitors, will perform under the safety and efficacy profiles compared with "broad-acting" agents, such as JAK inhibitors.

Effect of abrocitinib on skin biomarkers in patients with moderate-to-severe atopic dermatitis

BACKGROUND

This is the first report on the effects of abrocitinib, a Janus kinase 1-selective inhibitor, on the expression of skin biomarkers in patients with moderate-to-severe atopic dermatitis (AD).

METHODS

JADE MOA (NCT03915496) was a double-blind Phase 2a trial. Adults were randomly assigned 1:1:1 to receive monotherapy with once-daily abrocitinib 200 mg, abrocitinib 100 mg, or placebo for 12 weeks. The primary endpoint was change from baseline in markers of inflammation (matrix metalloproteinase [MMP]-12), epidermal hyperplasia (keratin-16 [KRT16]), T-helper 2 (Th2) immune response (C-C motif chemokine ligand [CCL]17, CCL18, and CCL26), and Th22 immune response (S100 calcium binding protein A8, A9, and A12 [S100A8, S100A9, and S100A12]) in skin through 12 weeks.

RESULTS

A total of 46 patients received abrocitinib 200 mg (n = 14), abrocitinib 100 mg (n = 16), or placebo (n = 16). Abrocitinib improved AD clinical signs and reduced itch. Gene expression of MMP-12, KRT16, S100A8, S100A9, and S100A12 was significantly decreased from baseline with abrocitinib 200 mg (at Weeks 2, 4, and 12) and abrocitinib 100 mg (at Weeks 4 and 12) in a dose-dependent manner. Abrocitinib 200 mg resulted in significant decreases from baseline in CCL17 expression at Week 12 and CCL18 expression at Weeks 2, 4, and 12; no significant decreases were observed for CCL26.

CONCLUSIONS

Alongside improvements in clinical signs and symptoms of AD, 12 weeks of abrocitinib treatment resulted in downregulation of genes associated with inflammation, epidermal hyperplasia, and Th2 and Th22 immune responses in the skin of patients with moderate-to-severe AD.

Topical Application of a PDE4 Inhibitor Ameliorates Atopic Dermatitis through Inhibition of Basophil IL-4 Production

Phosphodiesterase 4 inhibitors have been approved for the treatment of atopic dermatitis. However, the cellular and molecular mechanisms underlying their therapeutic effect remain to be fully elucidated. In this study, we addressed this unsolved issue by analyzing the action of difamilast, a novel phosphodiesterase 4 inhibitor, on an oxazolone-induced skin allergic inflammation commonly used as a mouse model of atopic dermatitis. Topical application of difamilast ameliorated skin inflammation in association with reduced IL-4 expression even when the treatment commenced 4 days after the initiation of oxazolone challenge, showing its therapeutic effect on atopic dermatitis. IL-4-deficient mice displayed milder skin inflammation than did wild-type mice, and the difamilast treatment had little or no further therapeutic effect. This was also the case in mice depleted of basophils, predominant producers of IL-4 in the skin lesion, suggesting that difamilast may act on basophils. Notably, basophils accumulating in the skin lesion showed highly upregulated expression of Pde4b encoding the B subtype of the phosphodiesterase 4 family. Difamilast suppressed IL-4 production from basophils activated in vitro, at least in part, through inhibition of ERK phosphorylation. Taken together, difamilast appeared to ameliorate atopic dermatitis inflammation through the suppression of basophil IL-4 production in the skin lesion.

Benvitimod Inhibits IL-4- and IL-13-Induced Tight Junction Impairment by Activating AHR/ARNT Pathway and Inhibiting STAT6 Phosphorylation in Human Keratinocytes

Tight junctions are involved in skin barrier functions. In this study, the expression of CLDN1, CLDN4, and OCLN was found to decrease in skin lesions of atopic dermatitis by bioinformatics analysis. Immunohistochemistry staining in skin specimens from 12 patients with atopic dermatitis and 12 healthy controls also showed decreased CLDN1, CLDN4, and OCLN expression in atopic dermatitis lesions. In vitro studies showed that IL-4 and IL-13 downregulated CLDN1, CLDN4, and OCLN expression in HaCaT cells as well as CLDN4 and OCLN expression in human primary keratinocytes. This effect, which was mediated through the Jak-signal transducer and activator of transcription 6 signaling pathway, increased paracellular flux of 4-kDa dextran. Benvitimod, a new drug for atopic dermatitis, upregulated CLDN4 and OCLN through the aryl hydrocarbon receptor/aryl hydrocarbon receptor nuclear translocator pathway. Benvitimod induced nuclear translocation of NRF2 and reduced production of ROS in keratinocytes, thus inhibiting IL-4-/IL-13-induced CLDN1 downregulation and signal transducer and activator of transcription 6 phosphorylation. These results indicate that T helper 2 cytokines are involved in tight junction impairment, and benvitimod can inhibit these effects.

Boron-containing carbonic anhydrases inhibitors

Over the last decades, the medicinal chemistry of boron-based compounds has been extensively explored, designing valuable small molecule drugs to tackle diseases and conditions, such as cancer, infections, inflammatory and neurological disorders. Notably, boron has proven to also be a valuable element for the development of inhibitors of the metalloenzymes carbonic anhydrases (CAs), a class of drug targets with significant potential in medicinal chemistry. Incorporating boron into carbonic anhydrase inhibitors (CAIs) can modulate the ligand ability to recognize the target and/or influence selectivity towards different CA isoforms, using the tail approach and boron-based tails. The electron-deficient nature of boron and its associated properties have also led to the discovery of novel zinc-binding CAIs, such as boronic acids and the benzoxaboroles, capable of inhibiting the CAs upon a Lewis acid-base mechanism of action. The present manuscript reviews the state-of-the-art of boron-based CAIs. As research in the applications of boron compounds in medicinal chemistry continues, it is anticipated that new boron-based CAIs will soon expand the current array of such compounds. However, further research is imperative to fully unlock the potential of boron-based CAIs and to advance them towards clinical applications.

Methotrexate for refractory adult atopic dermatitis leads to alterations in cutaneous IL-31 and IL-31RA expression

BACKGROUND

Methotrexate (MTX) is an alternative treatment for patients with moderate/severe atopic dermatitis (AD).

OBJECTIVE

The authors evaluated the effect of MTX on the cutaneous expression of cytokines and chemokines that are involved in the inflammatory response in adult AD patients who received treatment with methotrexate for 24 weeks.

METHODS

The authors conducted a prospective single-institution cohort study with 12 adults with moderate/severe AD who received oral MTX (15 mg/wk for 24 wks) and 10 non-atopic matched controls. The comparison was made of skin biopsies of lesional and non-lesional skin, pre- and post MTX treatment. The authors analyzed mean epidermal thickness and expression of IL-31, IL-31RA, OSMR, TSLP, Ki67, IL-4 mRNA, IL-6, IL-10, TNF-α, IFN-γ, TARC, and CCL-22.

RESULTS

There was a reduction in mean epidermal thickness (p = 0.021), an increase in IL-31RA expression (immunohistochemistry) in the epidermis (p = 0.016) and a decrease in IL-31 gene expression (p = 0.019) on lesional AD skin post-MTX treatment. No significant changes in the cutaneous expression of the other evaluated markers were identified.

STUDY LIMITATIONS

Small sample size and limited length of follow-up.

CONCLUSIONS

Treatment with MTX in adults with moderate/severe AD reduced epidermal hyperplasia and changed the cutaneous expression of inflammatory cytokines and receptors that are mainly related to pruritus, including IL-31 and IL-31RA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03327116.

Topical Prescription Management

With recent advances in topical therapies for atopic dermatitis (AD), steroid-sparing options like calcineurin inhibitors, Janus kinase (JAK) inhibitors, and phosphodiesterase-4 (PDE-4) inhibitors are becoming mainstays in therapy, underscoring the importance of careful selection and usage of topical corticosteroids (TCSs) to minimize side effects. Alongside the necessity of emollient use, these steroid-sparing alternatives offer rapid itch relief and efficacy in improving disease severity. While TCSs still hold a prominent role in AD management, promising novel topical treatments like tapinarof and live biotherapeutics to modulate the skin microbiome are also discussed. Overall, the recent addition of novel topical therapies offers diverse options for AD management and underscores the importance of topical treatments in the management of AD.

IL-22RA2 Is a SMAD7 Target Mediating the Alleviation of Dermatitis and Psoriatic Phenotypes in Mice

Long-term management of inflammatory skin diseases is challenging because of side effects from repeated use of systemic treatments or topical corticosteroids. This study sought to identify the mechanisms and developmental therapeutics for these diseases using genetic models and pharmacological approaches. We found that mice overexpressing SMAD7 in keratinocytes but not mice overexpressing the N-terminal domain of SMAD7 (i.e., N-SMAD7) were resistant to imiquimod-induced T helper 1/17- and T helper 2-type inflammation. We generated a Tat-PYC-SMAD7 (truncated SMAD7 protein encompassing C-terminal SMAD7 and PY motif fused with cell-penetrating Tat peptide). Topically applied Tat-PYC-SMAD7 to inflamed skin entered cells upon contact and attenuated imiquimod-, 2,4-dinitrofluorobenzene-, and tape-stripping-induced inflammation. RNA-sequencing analyses of mouse skin exposed to these insults showed that in addition to inhibiting TGFβ/NF-κB, SMAD7 blunted IL-22/signal transducer and activator of transcription 3 activation and associated pathogenesis, which is due to SMAD7 transcriptionally upregulating IL-22 antagonist IL-22RA2. Mechanistically, SMAD7 facilitated nuclear translocation and DNA binding of C/EBPβ to IL22RA2 promoter for IL22RA2 transactivation. Consistent with the observations in mice mentioned earlier, transcript levels of IL22RA2 were increased in human atopic dermatitis and psoriasis lesions with clinical remission. Our study identified the anti-inflammation functional domain of SMAD7 and suggests the mechanism and feasibility for developing SMAD7-based biologics as a topical therapy for skin inflammatory disorders.

Current and Emerging Therapies for Atopic Dermatitis in the Elderly

Atopic dermatitis (AD) in the elderly has recently emerged as a distinct subgroup of AD, garnering widespread concern due to its increasing global incidence rate. Epidermal barrier dysfunction, inflammatory response, and chronic pruritus interact with each other, contributing to the pathogenesis and pathophysiology of AD in the elderly. Although fundamental medications are essential for managing AD in the elderly, older adults often struggle with regular usage of moisturizing emollients, topical medications, and avoidance of environmental triggers, leading to recurrent or even exacerbated disease progression. Therefore, a systematic medication approach is necessary to control pruritus and skin lesions. Traditional systemic treatments may not adequately meet the treatment needs of moderate and severe AD in the elderly and may even pose certain safety risks. Biologics and Janus kinase (JAK) inhibitors, exhibiting excellent clinical efficacy, have made significant breakthroughs in AD treatment. Existing evidence suggests that dupilumab, a human monoclonal IgG4 antibody, has been confirmed as an effective and safe first-line systematic treatment for moderate to severe AD in the elderly, with no notable differences between adults and the elderly. However, the limited inclusion of elderly patients in related clinical studies hinders the generalizability of these findings. As older patients face a higher risk of adverse events with JAK inhibitors, JAK inhibitors are recommended when no other suitable treatment options are available. Obtaining population-specific data is crucial for making evidence-based treatment choices when managing AD in older adults with JAK inhibitors.

Epidermal biomarkers of the skin barrier in atopic and contact dermatitis

Dysfunction of the skin barrier plays a critical role in the initiation and progression of inflammatory skin diseases, such as atopic dermatitis and contact dermatitis. Epidermal biomarkers can aid in evaluating the functionality of the skin barrier and understanding the mechanisms that underlay its impairment. This narrative review provides an overview of recent studies on epidermal biomarkers associated with the function and integrity of the skin barrier, and their application in research on atopic dermatitis and contact dermatitis. The reviewed studies encompass a wide spectrum of molecular, morphological and biophysical biomarkers, mainly obtained from stratum corneum tape strips and biopsies. Lipids, natural moisturizing factors, and structural proteins are the most frequently reported molecular biomarkers. Additionally, corneocyte surface topography and elasticity show potential as biomarkers for assessing the physical barrier of the skin. In contact dermatitis studies, biomarkers are commonly employed to evaluate skin irritation and differentiate between irritant and allergic contact dermatitis. In atopic dermatitis, biomarkers are primarily utilized to identify differences between atopic and healthy skin, for predictive purposes, and monitoring response to therapies. While this overview identifies potential biomarkers for the skin barrier, their validation as epidermal biomarkers for atopic dermatitis and contact dermatitis has yet to be established.

Novel Vehicles For Drug Delivery in Atopic Dermatitis: A Narrative Review

INTRODUCTION

Atopic dermatitis (AD) causes dry and itchy skin and inflammation that severely impairs the quality of life of affected children and adults. While topical glucocorticosteroid application is typically the first-line treatment of choice, steroid treatment is associated with side effects and, increasingly, patient concerns about prolonged use. Novel drugs and drug delivery vehicles are required for patients with AD.

OBJECTIVES

To summarize the current literature on novel topical agents for atopic dermatitis and novel delivery vehicles.

METHODS

A literature search was conducted, and a narrative review was compiled to summarize recent evidence.

RESULTS

Novel topical drugs approved or in late-phase clinical trials for the treatment of AD include the Janus kinase inhibitor ruxolitinib, the phosphodiesterase-4 inhibitors crisaborole, and roflumilast, and the aryl hydrocarbon receptor activator tapinarof. While current topical drugs for AD are delivered via creams, ointments, gels, and related vehicles, novel delivery approaches such as electrospun patches, sprays, liposomes, nanoparticles, and lasers are being developed to enhance transdermal delivery, reduce side effects, and increase treatment adherence.

CONCLUSIONS

Topical application of creams or ointments is currently the predominant vehicle for the delivery of atopic dermatitis drugs. In vitro studies on novel vehicles show promising results to overcome the issues associated with topical delivery. Still, these findings have to be corroborated by controlled studies with human patients in the future.

Emerging nanotechnology backed formulations for the management of atopic dermatitis

Atopic dermatitis is a prevalent chronic skin inflammation affecting 2.1 to 4.1% of adults globally. The complexity of its pathogenesis and the relapsing nature make it challenging to treat. Current treatments follow European Academy of Dermatology and Venerology guidelines, but advanced cases with recurring lesions lack effective therapies. To address this gap, researchers are exploring nanotechnology for targeted drug delivery. Nanoparticles offer benefits such as improved drug retention, stability, controlled release and targeted delivery through the disrupted epidermal barrier. This integrated review evaluates the current state of AD treatment and highlights the potential of novel nano-formulations as a promising approach to address the disease.

Crisaborole Inhibits Itch and Pain by Preventing Neutrophil Infiltration in a Mouse Model of Atopic Dermatitis

Crisaborole, a phosphodiesterase 4 (PDE4) inhibitor, has been approved for the treatment of mild to moderate atopic dermatitis. Atopic dermatitis is often associated with increased pain. Using a mouse model, this study investigated whether crisaborole suppresses pain associated with atopic dermatitis and the potential mechanisms underlying it. The mouse model for atopic dermatitis was developed by repeatedly applying MC903. MC903-treated mice had increased spontaneous scratching (itch-related behaviour) and wiping behaviour (pain-related behaviour). Crisaborole was topically applied to the cheek skin of MC903-treated mice, and it reduced both itch- and pain-related behaviours in these mice. Immunofluorescence staining revealed that crisaborole reduced neutrophil infiltration and interaction of neutrophils with sensory neurones. Intradermal injection of S100A8/A9, proinflammatory neutrophil mediator, enhanced not only itch-related behaviours evoked by histamine or chloroquine, but also pain-related behaviours evoked by capsaicin. Calcium imaging of mouse dorsal root ganglion neurones revealed that pretreatment with S100A8/A9 significantly increased calcium responses to histamine and capsaicin, and the proportion of chloroquine-sensitive neurones. These findings suggest that the PDE4 inhibitor reduces itch and pain, in part by inhibiting infiltration of S100A8/A9-containing neutrophils in a mouse model of MC903-induced atopic dermatitis.

PDE4 inhibitors for disease therapy: advances and future perspective

The PDE4 enzyme family is specifically responsible for hydrolyzing cAMP and plays a vital role in regulating the balance of second messengers. As a crucial regulator in signal transduction, PDE4 has displayed promising pharmacological targets in a variety of diseases, for which its inhibitors have been used as a therapeutic strategy. This review provides a comprehensive summary of the development of PDE4 inhibitors in the past few years, along with the structure, clinical and research progress of multiple inhibitors of PDE4, focusing on the research and development strategies of PDE4 inhibitors. We hope our analysis will provide a significant reference for the future development of new PDE4 inhibitors.

Guidelines of care for the management of atopic dermatitis in adults with topical therapies

BACKGROUND

New evidence has emerged since the 2014 guidelines that further informs the management of atopic dermatitis (AD) with topical therapies. These guidelines update the 2014 recommendations for management of AD with topical therapies.

OBJECTIVE

To provide evidence-based recommendations related to management of AD in adults using topical treatments.

METHODS

A multidisciplinary workgroup conducted a systematic review and applied the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) approach for assessing the certainty of evidence and formulating and grading recommendations.

RESULTS

The workgroup developed 12 recommendations on the management of AD in adults with topical therapies, including nonprescription agents and prescription topical corticosteroids (TCS), calcineurin inhibitors (TCIs), Janus kinase (JAK) inhibitors, phosphodiesterase-4 inhibitors (PDE-4), antimicrobials, and antihistamines.

LIMITATIONS

The pragmatic decision to limit the literature review to English-language randomized trials may have excluded data published in other languages and relevant long-term follow-up data.

CONCLUSIONS

Strong recommendations are made for the use of moisturizers, TCIs, TCS, and topical PDE-4 and JAK inhibitors. Conditional recommendations are made for the use of bathing and wet wrap therapy and against the use of topical antimicrobials, antiseptics, and antihistamines.

PDE4 inhibition by difamilast regulates filaggrin and loricrin expression via keratinocyte proline-rich protein in human keratinocytes

BACKGROUND

Difamilast, a topical phosphodiesterase 4 (PDE4) inhibitor, has been shown to be effective for treating atopic dermatitis (AD), but the molecular mechanism involved is unclear. Since skin barrier dysfunction including reduced expression of filaggrin (FLG) and loricrin (LOR) contributes to AD development, difamilast treatment may be able to improve this dysfunction. PDE4 inhibition increases transcriptional activity of cAMP-responsive element binding protein (CREB). Therefore, we hypothesized that difamilast may affect FLG and LOR expression via CREB in human keratinocytes.

OBJECTIVE

To elucidate the mechanism by which difamilast regulates FLG and LOR expression via CREB in human keratinocytes.

METHODS

We analyzed normal human epidermal keratinocytes (NHEKs) treated with difamilast.

RESULTS

We observed increases of intracellular cAMP levels and CREB phosphorylation in difamilast (5 μM)-treated NHEKs. Next, we found that difamilast treatment increased mRNA and protein levels of FLG and LOR in NHEKs. Since reduced expression of keratinocyte proline-rich protein (KPRP) is reported to be involved in skin barrier dysfunction in AD, we examined KPRP expression in difamilast-treated NHEKs. We found that difamilast treatment increased mRNA and protein levels of KPRP in NHEKs. Furthermore, KPRP knockdown using siRNA transfection abolished the upregulation of FLG and LOR in difamilast-treated NHEKs. Finally, CREB knockdown canceled the upregulation of FLG, LOR, and KPRP in difamilast-treated NHEKs, indicating that PDE4 inhibition by difamilast treatment positively regulates FLG and LOR expression via the CREB-KPRP axis in NHEKs.

CONCLUSION

These findings may provide further guidance for therapeutic strategies in the treatment of AD using difamilast.

Crisaborole efficacy in murine models of skin inflammation and Staphylococcus aureus infection

Phosphodiesterase 4 (PDE4) is highly expressed in keratinocytes and immune cells and promotes pro-inflammatory responses upon activation. The activity of PDE4 has been attributed to various inflammatory conditions, leading to the development and approval of PDE4 inhibitors as host-directed therapeutics in humans. For example, the topical PDE4 inhibitor, crisaborole, is approved for the treatment of mild-to-moderate atopic dermatitis and has shown efficacy in patients with psoriasis. However, the role of crisaborole in regulating the immunopathogenesis of inflammatory skin diseases and infection is not entirely known. Therefore, we evaluated the effects of crisaborole in multiple mouse models, including psoriasis-like dermatitis, AD-like skin inflammation with and without filaggrin mutations, and Staphylococcus aureus skin infection. We discovered that crisaborole dampens myeloid cells and itch in the skin during psoriasis-like dermatitis. Furthermore, crisaborole was effective in reducing skin inflammation in the context of filaggrin deficiency. Importantly, crisaborole reduced S. aureus skin colonization during AD-like skin inflammation. However, crisaborole was not efficacious in treating S. aureus skin infections, even as adjunctive therapy to antibiotics. Taken together, we found that crisaborole reduced itch during psoriasis-like dermatitis and decreased S. aureus skin colonization upon AD-like skin inflammation, which act as additional mechanisms by which crisaborole dampens the immunopathogenesis in mouse models of inflammatory skin diseases. Further examination is warranted to translate these preclinical findings to human disease.

Pharmacology of orismilast, a potent and selective PDE4 inhibitor

BACKGROUND

There remains an unmet need for oral medications that are safe and efficacious for long-term management of chronic inflammatory skin diseases (CISD). Inhibition of phosphodiesterase 4 (PDE4) can modulate a broad range of pro-inflammatory cytokines that play a major role in CISD pathogenesis. Orismilast is a second generation PDE4 inhibitor in clinical development for CISD treatment.

OBJECTIVES

The objective of this study was to examine the PDE4 enzymatic activity and anti-inflammatory effects of orismilast in vitro, ex vivo, and in vivo.

METHODS

The PDE1-11 enzymatic activity of orismilast was tested in vitro using a single concentration of 308 nM orismilast. The PDE4 selectivity and inhibitory potency was further examined in a radiometric assay. Orismilast was tested on human whole blood and human peripheral blood mononuclear cells (PBMC) to determine effects on its cytokine secretion and inhibition profile ex vivo. Orismilast was orally administered in a murine model of chronic oxazolone-induced ear skin inflammation. Ear thickness, a marker of inflammation, and inflammatory cytokines were analysed.

RESULTS

Orismilast selectively inhibited PDE4 and demonstrated potent inhibition of PDE4B and PDE4D subtype splice variants in vitro. Orismilast inhibited whole blood and PBMC production of tumour necrosis factor α (TNFα), and the secretion of T-helper (Th)1 (TNFα and IFNγ), Th17 (IL-22 and IL-23), and Th2 (IL-4, IL-5, and IL-13) related cytokines in PBMC. In vivo, 10 and 30 mg/kg doses of orismilast significantly reduced ear thickness and inflammation markers (p < 0.0001, respectively).

CONCLUSION

Orismilast displayed selective and potent PDE4 inhibition and broad-spectrum anti-inflammatory activity in several pre-clinical models. The results of the study support clinical development of oral orismilast as a novel treatment option for CISD including psoriasis, atopic dermatitis, and hidradenitis suppurativa.

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.

Treatment Strategies for Chronic Pruritus and Eczema/Dermatitis in Older Adults Under the Category of Chronic Eczematous Eruptions of Aging (CEEA)

Chronic eczematous eruptions of aging (CEEA) refers to a heterogenous group of longstanding, pruritic eczematous dermatoses with an unidentified etiology, or those which do not meet strict disease criteria. The literature has not yet established a single ubiquitous disease or term for these eruptions in adults over the age of 65 years. Instead, CEEA is attributed various names, including immunologic eruption of aging, and eruption of immunosenescence. Atopic dermatitis in the elderly, eczema in the elderly, and late- or adult-onset atopic dermatitis or eczema likely also fall under the umbrella of CEEA, given that older patients often do not meet strict criteria for atopic dermatitis. As a reflection of such terminological heterogeneity, CEEA does not have a standardized workup algorithm. This lack of uniformity can obscure the ability to study and understand appropriate treatments for this condition. Yet, as providers become increasingly aware of CEEA and more comfortable in making this diagnosis in older adults, it is necessary that dermatologists understand the safety and efficacy of common CEEA treatments in this population. Here, we discuss special considerations, challenges, and recommendations for treating older adults with CEEA with topical and systemic therapeutics. We provide an overview of therapeutic strategies and potential barriers to treatment and discuss the essential role of shared decision making when caring for this patient population.

Successful treatment of vitiligo with crisaborole ointment: a report of two cases

As selective PDE-4 small molecule inhibitor, Crisaborole has been used with success in atopic dermatitis and psoriasis. Here we report two vitiligo patients successfully treated with crisaborole ointment.

Topical Administration of Crisaborole in Mild to Moderate Atopic Dermatitis: A Systematic Review and Meta-Analysis

Background. Crisaborole has been considered a promising alternative for topical treatment of atopic dermatitis (AD), mainly supported by AD-301 and AD-302. However, critical insights into these two studies have previously been proposed. Objective. To make a comprehensive assessment of the application of crisaborole in mild to moderate AD. Methods. A systematic review and meta-analysis were conducted, in which only randomized controlled trials comparing the application of crisaborole twice daily to vehicle or other active treatment in patients with mild to moderate AD were included. The selection of outcomes was based on the recommendation of the HOME initiative. Patient-reported symptoms, clinician-reported signs, health-related quality of life, and the safety of crisaborole were all assessed using appropriate measurement instruments. Results. Eight RCTs with 2266 patients were included in the pooled analysis. Compared to those treated with vehicle, patients on crisaborole experienced a greater improvement in NRS (MD −0.70; 95% CI −0.94 to −0.47), POEM (MD −3.50; 95% CI −4.34 to −2.66), EASI (MD −14.49%; 95% CI −18.24% to −10.73%), ISGA (RR 1.45; 95% CI 1.28 to 1.63), DLQI (MD −1.54; 95% CI −2.17 to −0.92), and DFI (MD −1.16; 95% CI −1.72 to −0.59) during the 4-week treatment. More patients achieved EASI 75 (RR 1.71; 95% CI 1.43 to 2.04) with crisaborole administration. There was no significant difference between two interventions in the incidence of AEs (RR 1.12; 95% CI 0.98 to 1.29), SAEs (RR 1.89; 95% CI 0.47 to 7.60), or AE-related withdrawal (RR 0.87; 95% CI 0.47 to 1.60). One RCT also made comparison between crisaborole and pimecrolimus, suggesting that no significant difference was detected in the improvement of EASI or NRS at most time points. Conclusion. High-quality evidence was provided to demonstrate that the short-term application of crisaborole is safe and efficacious for the treatment of mild to moderate AD. The practical efficacy of crisaborole is similar to that of pimecrolimus.

Therapeutic treatment with phosphodiesterase-4 inhibitors alleviates kidney injury and renal fibrosis by increasing MMP-9 in a doxorubicin-induced nephrotoxicity mouse model

Nephrotic syndrome (NS) is associated with kidney dysfunction and is an important cause of morbidity and mortality in industrialized countries. Here, we evaluated the effects of the phosphodiesterase-4 (PDE-4) inhibitors rolipram and roflumilast on a doxorubicin-induced NS model. Early-stage rolipram treatment preserved glomerular filtration barrier function, as indicated by reduced serum protein and albumin loss and the prevention of hypercholesterolemia. These effects were associated with reduced glomerular and tubular lesions and abrogated renal cell apoptosis. In addition, rolipram treatment reduced inflammation, which was characterized by a decrease in macrophage accumulation and reduced levels of CCL2 and TNF in the kidneys. Rolipram also reduced renal fibrosis, which was associated with decreased α-smooth muscle actin (α-SMA) area and increased metalloproteinase 9 (MMP9) activity in renal tissue. Late-stage rolipram or roflumilast treatment preserved glomerular filtration barrier function, as characterized by reduced serum albumin loss, decreased proteinuria, and the prevention of hypercholesterolemia. Importantly, only roflumilast treatment was associated with a reduction in glomerular and tubular lesions at this time point. In addition, both rolipram and roflumilast reduced renal tissue fibrosis and MMP9 activity in renal tissue.

Efficacy of topical and systemic treatments for atopic dermatitis on pruritus: A systematic literature review and meta-analysis

Introduction

Pruritus is a major and burdensome symptom in atopic dermatitis (AD). The number of systemic treatments available for AD has increased recently, enabling improved patient relief.

Objective

To evaluate the effect of AD treatments on pruritus.

Methods

A systematic literature review and a meta-analysis were conducted to evaluate and compare the effects of treatment used in AD on pruritus. PubMed and Embase databases were searched to find articles published between January 1990 and December 2021. Topical and systemic treatments were studied in patients aged ≥10 years.

Results

Among the 448 articles identified, 56 studies were retained in the systematic review. A total of 15 studies evaluated topical treatments: topical corticosteroids (TCS; 2), calcineurin inhibitors (6), PDE4 inhibitors (3), and Jak inhibitors (4). A total of five studies were included in the meta- analysis. All treatments had a positive effect on pruritus, with a mean overall reduction of 3.32/10, 95% IC [2.32-4.33]. The greatest reduction was observed with halometasone (mean: 4.75), followed by tofacitinib 2% (mean: 4.38). A total of 41 studies evaluated systemic therapies: cyclosporine (6), phototherapy (5), azathioprine (2), dupilumab (9), anti-IL 13 (5), nemolizumab (3), Jak inhibitors (9), mepolizumab (1), and apremilast (1). A total of 17 studies were included in 2 meta-analyses according to the concomitant use or not of TCS. In the meta-analysis without TCS, the overall decrease was 3.07/10, 95% IC [2.58-3.56]. The molecules with the highest efficacy on pruritus were upadacitinib 30 mg (mean: 4.90) and nemolizumab (mean: 4.81).

Discussion

The therapeutic arsenal for AD has increased rapidly, and many molecules are under development. The primary endpoint of clinical trials is most often a score that assesses the severity of AD; however, the assessment of pruritus is also essential. The majority of molecules have a positive effect on pruritus, but the improvement varies between them. Efficacy on pruritus is not always correlated with efficacy on AD lesions; therefore, these two criteria are crucial to evaluate. The limitations of this study were the heterogeneity in the assessment of pruritus, the moment of the assessment, and the concomitant application of TCS or not for studies evaluating systemics. In the future, it would be useful to use standardized criteria for assessing pruritus.

Establishment and validation of evaluation models for post-inflammatory pigmentation abnormalities

Post-inflammatory skin hyper- or hypo-pigmentation is a common occurrence with unclear etiology. There is currently no reliable method to predict skin pigmentation outcomes after inflammation. In this study, we analyzed the 5 GEO datasets to screen for inflammatory-related genes involved in melanogenesis, and used candidate cytokines to establish different machine learning (LASSO regression, logistic regression and Random Forest) models to predict the pigmentation outcomes of post-inflammatory skin. Further, to further validate those models, we evaluated the role of these candidate cytokines in pigment cells. We found that IL-37, CXCL13, CXCL1, CXCL2 and IL-19 showed high predictive value in predictive models. All models accurately classified skin samples with different melanogenesis-related gene scores in the training and testing sets (AUC>0.7). Meanwhile, we mainly evaluated the effects of IL-37 in pigment cells, and found that it increased the melanin content and expression of melanogenesis-related genes (MITF, TYR, TYRP1 and DCT), also enhanced tyrosinase activity. In addition, CXCL13, CXCL1, CXCL2 and IL-19 could down-regulate the expression of several melanogenesis-related genes. In conclusion, evaluation models basing on machine learning may be valuable in predicting outcomes of post-inflammatory pigmentation abnormalities. IL-37, CXCL1, CXCL2, CXCL13 and IL-19 are involved in regulating post-inflammatory pigmentation abnormalities.

New and Upcoming Topical Treatments for Atopic Dermatitis: A Review of the Literature

Atopic dermatitis (AD) is a chronic inflammatory dermatosis with periods of exacerbation and remissions. AD is characterized by intense, persistent pruritus and heterogeneity in clinical symptomatology and severity. Therapeutic goals include the amelioration of cutaneous eruptions, diminishing relapses and eventually the disease burden. To date, topical corticosteroids (TCS) and calcineurin inhibitors (TCI) have yet been deemed the mainstay of topical treatments in AD management. Nevertheless, despite their indisputable efficiency, TCS and TCI are not indicated for continuous long-term use given their safety profile. While research in AD has concentrated predominantly on systemic therapies, more than 30 novel topical compounds are under development. The existing data appear encouraging, with some regimens that are already FDA-approved (ruxolitinib was the most recent in September 2021) and several pharmaceutical pipeline products for mild-to-moderate AD that are in an advanced stage of development, such as tapinarof, difamilast and roflumilast. Larger, long-term studies are still required to evaluate the efficacy and safety of these novel compounds in the long run and weigh their advantages over present treatments. In this review, we aim to provide an overview of the latest knowledge about AD topical treatments, echoing upcoming research trends.

Treatment Options for Troublesome Itch

Itch (or pruritus) is an unpleasant sensation, inducing the desire to scratch. It is also a major and distressing symptom of many skin and systemic diseases. The involvement of histamine, which is a major itch mediator, has been extensively examined. Recent studies suggest that histamine-independent pathways may play roles in chronic itch. Therefore, antihistamines are not always effective in the treatment of patients with chronic itch. The development of biologics and κ-opioid receptor (KOR) agonists has contributed to advances in the treatment of itch; however, since biologics are expensive for patients to purchase, some patients may limit or discontinue their use of these agents. Furthermore, KOR agonists need to be prescribed with caution due to risks of side effects in the central nervous system. Janus kinase (JAK) inhibitors are sometimes associated with side effects, such as infection. In this review, we summarize antidepressants, antineuralgics, cyclosporine A, antibiotics, crotamiton, phosphodiesterase 4 inhibitor, botulinum toxin type A, herbal medicines, phototherapy, and acupuncture therapy as itch treatment options other than antihistamines, biologics, opioids, and JAK inhibitors; we also explain their underlying mechanisms of action.

Phenformin Down-Regulates c-Myc Expression to Suppress the Expression of Pro-Inflammatory Cytokines in Keratinocytes

The treatment of many skin inflammation diseases, such as psoriasis and atopic dermatitis, is still a challenge and inflammation plays important roles in multiple stages of skin tumor development, including initiation, promotion and metastasis. Phenformin, a biguanide drug, has been shown to play a more efficient anti-tumor function than another well-known biguanide drug, metformin, which has been reported to control the expression of pro-inflammatory cytokines; however, little is known about the effects of phenformin on skin inflammation. This study used a mouse acute inflammation model, ex vivo skin organ cultures and in vitro human primary keratinocyte cultures to demonstrate that phenformin can suppress acute skin inflammatory responses induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in vivo and significantly suppresses the pro-inflammatory cytokines IL-1β, IL-6 and IL-8 in human primary keratinocytes in vitro. The suppression of pro-inflammatory cytokine expression by phenformin was not directly through regulation of the MAPK or NF-κB pathways, but by controlling the expression of c-Myc in human keratinocytes. We demonstrated that the overexpression of c-Myc can induce pro-inflammatory cytokine expression and counteract the suppressive effect of phenformin on cytokine expression in keratinocytes. In contrast, the down-regulation of c-Myc produces effects similar to phenformin, both in cytokine expression by keratinocytes in vitro and in skin inflammation in vivo. Finally, we showed that phenformin, as an AMPK activator, down-regulates the expression of c-Myc through regulation of the AMPK/mTOR pathways. In summary, phenformin inhibits the expression of pro-inflammatory cytokines in keratinocytes through the down-regulation of c-Myc expression to play an anti-inflammation function in the skin.

Current emerging and investigational drugs for the treatment of chronic hand eczema

INTRODUCTION

: Chronic hand eczema (CHE) is a highly prevalent, burdensome condition associated with functional impairment. Currently, topical therapeutics are the mainstay of CHE management. However, many cases are refractory to existing topical therapeutics, and the few existing systemic options are often limited in efficacy and by their side effect profiles.

AREAS COVERED

: Following a brief overview of CHE pathogenesis and existing treatments, this review will outline the mechanisms and available data on emerging and investigational drugs currently being studied in clinical trials for the treatment of CHE.

EXPERT OPINION

: Immunomodulatory drugs such as topical and systemic JAK inhibitors and Th2-targeting antibodies such as dupilumab are currently under investigation for CHE treatment, with early promise. Management of CHE will likely move toward more targeted treatments through clinical trials and away from broad immunosuppressants such as cyclosporine and methotrexate, which have previously been investigated for CHE and have more side effects. In coming years, CHE patients may benefit from a wider range of both topical and systemic therapeutics that target immune pathways relevant to the various CHE subtypes.

Safety profile and tolerability of topical phosphodiesterase 4 inhibitors for the treatment of atopic dermatitis: A systematic review and meta-analysis

Objective

Methods

Results

Conclusions

Type 2 Inflammation Contributes to Skin Barrier Dysfunction in Atopic Dermatitis

Skin barrier dysfunction, a defining feature of atopic dermatitis (AD), arises from multiple interacting systems. In AD, skin inflammation is caused by host-environment interactions involving keratinocytes as well as tissue-resident immune cells such as type 2 innate lymphoid cells, basophils, mast cells, and T helper type 2 cells, which produce type 2 cytokines, including IL-4, IL-5, IL-13, and IL-31. Type 2 inflammation broadly impacts the expression of genes relevant for barrier function, such as intracellular structural proteins, extracellular lipids, and junctional proteins, and enhances Staphylococcus aureus skin colonization. Systemic anti‒type 2 inflammation therapies may improve dysfunctional skin barrier in AD.

A new ex vivo skin model for mechanistic understanding of putative anti-inflammatory topical therapeutics

Several in vitro models have been designed as test systems for inflammatory skin conditions, commonly using cell-culture or reconstructed human epidermis approaches. However, these systems poorly recapitulate the physiology and, importantly, the metabolism and biochemical activity of skin in vivo, whereas ex vivo skin culture models can retain these features of the tissue. Our objective was to develop a human ex vivo skin culture model to explore the pathophysiology of inflammatory dermatoses and for preclinical testing of potential therapeutic treatments. Following exogenous stimulation, tissue integrity and ability to induce inflammatory gene expression was retained, and stimulant concentrations and duration was optimised to mimic published data from inflammatory clinical biopsies of dermatitis and psoriasis patients. The validity and utility of the model was demonstrated when challenged with 5 drugs including a corticosteroid and vitamin D3 analogue, where inflammatory biomarkers were regulated in a manner consistent with the drugs' reported in vivo mechanisms of action. This model retains important inflammatory gene signals observed in human inflammatory dermatoses for preclinical evaluation of novel therapeutics.

Early intervention and prevention of allergic diseases

Food allergy (FA) is now one of the most common chronic diseases of childhood often lasting throughout life and leading to significant worldwide healthcare burden. The precise mechanisms responsible for the development of this inflammatory condition are largely unknown; however, a multifactorial aetiology involving both environmental and genetic contributions is well accepted. A precise understanding of the pathogenesis of FA is an essential first step to developing comprehensive prevention strategies that could mitigate this epidemic. As it is frequently preceded by atopic dermatitis and can be prevented by early antigen introduction, the development of FA is likely facilitated by the improper initial presentation of antigen to the developing immune system. Primary oral exposure of antigens allowing for presentation via a well-developed mucosal immune system, rather than through a disrupted skin epidermal barrier, is essential to prevent FA. In this review, we present the data supporting the necessity of (1) an intact epidermal barrier to prevent epicutaneous antigen presentation, (2) the presence of specific commensal bacteria to maintain an intact mucosal immune system and (3) maternal/infant diet diversity, including vitamins and minerals, and appropriately timed allergenic food introduction to prevent FA.

Clinical Implication of Phosphodiesterase-4-Inhibition

The pleiotropic function of 3′,5′-cyclic adenosine monophosphate (cAMP)-dependent pathways in health and disease led to the development of pharmacological phosphodiesterase inhibitors (PDE-I) to attenuate cAMP degradation. While there are many isotypes of PDE, a predominant role of PDE4 is to regulate fundamental functions, including endothelial and epithelial barrier stability, modulation of inflammatory responses and cognitive and/or mood functions. This makes the use of PDE4-I an interesting tool for various therapeutic approaches. However, due to the presence of PDE4 in many tissues, there is a significant danger for serious side effects. Based on this, the aim of this review is to provide a comprehensive overview of the approaches and effects of PDE4-I for different therapeutic applications. In summary, despite many obstacles to use of PDE4-I for different therapeutic approaches, the current data warrant future research to utilize the therapeutic potential of phosphodiesterase 4 inhibition.

Th1, Th2 and Th17 inflammatory pathways predict cardiometabolic protein expression in serum of COVID-19 patients

A predominant source of complication in SARS-CoV-2 patients arises from a severe systemic inflammation that can lead to tissue damage and organ failure. The high inflammatory burden of this viral...

Subgroup Analysis of Crisaborole for Mild-to-Moderate Atopic Dermatitis in Children Aged 2 to < 18 Years

OBJECTIVES

This post hoc analysis of pooled data from two phase III studies (AD-301: NCT02118766; AD-302: NCT02118792) explored the efficacy and safety of crisaborole ointment, 2%, a nonsteroidal phosphodiesterase 4 inhibitor, for the treatment of mild-to-moderate atopic dermatitis (AD) in pediatric patients (aged 2 to < 18 years) only, stratified by baseline characteristics.

METHODS

Pediatric patients with mild or moderate AD per Investigator's Static Global Assessment (ISGA) and percentage of treatable body surface area (%BSA) ≥ 5 at baseline were assessed. Crisaborole or vehicle (2:1 randomization ratio) was applied twice daily for 28 days. Of the 1313 pediatric patients included in this study, 874 received crisaborole and 439 received vehicle. ISGA success was defined as clear (0) or almost clear (1) with ≥ 2-grade improvement from baseline. Efficacy and safety were stratified by age group, sex, baseline ISGA, baseline %BSA per published severity strata, and prior AD therapy.

RESULTS

Overall, the proportions of crisaborole-treated and vehicle-treated pediatric patients with ISGA success at week 4 were 32.5 and 21.5%, respectively. ISGA success rates at day 29 (week 4) were generally higher in crisaborole-treated (21.9-38.1%) than vehicle-treated (15.7-26.9%) patients across subgroups. Rates of treatment-related application site pain were 2.4-10.1% for crisaborole-treated patients and 0.6-2.2% for vehicle-treated patients across subgroups. No new safety concerns were noted in any patient subgroup.

CONCLUSION

Crisaborole improved global disease severity and was reasonably well tolerated across all pediatric baseline characteristic subgroups. Application site discomfort was greater with crisaborole than with vehicle, but few patients discontinued treatment.

GOV REGISTRATION NUMBERS

NCT02118766; NCT02118792 (registration date: April 21, 2014).

Skin barrier defects in atopic dermatitis: From old idea to new opportunity

Atopic dermatitis (AD) is the most common chronic skin inflammatory disease, with a profound impact on patients’ quality of life. AD varies considerably in clinical course, age of onset and degree to which it is accompanied by allergic and non-allergic comorbidities. Skin barrier impairment in both lesional and nonlesional skin is now recognized as a critical and often early feature of AD. This may be explained by a number of abnormalities identified within both the stratum corneum and stratum granulosum layers of the epidermis. The goal of this review is to provide an overview of key barrier defects in AD, starting with a historical perspective. We will also highlight some of the commonly used methods to characterize and quantify skin barrier function. There is ample opportunity for further investigative work which we call out throughout this review. These include: quantifying the relative impact of individual epidermal abnormalities and putting this in a more holistic view with physiological measures of barrier function, as well as determining whether these barrier-specific endotypes predict clinical phenotypes (e.g. age of onset, natural history, comorbidities, response to therapies, etc). Mechanistic studies with new (and in development) AD therapies that specifically target immune pathways, Staphylococcus aureus abundance and/or skin barrier will help us understand the dynamic crosstalk between these compartments and their relative importance in AD.

Ritlecitinib and brepocitinib demonstrate significant improvement in scalp alopecia areata biomarkers

BACKGROUND

Janus kinase (JAK) inhibitors have shown encouraging results in the treatment of alopecia areata (AA), an autoimmune form of hair loss, in small, uncontrolled studies and case reports.

OBJECTIVE

We conducted a biopsy substudy during the randomized, double-blind, placebo-controlled first 24 weeks of a phase 2a clinical trial that evaluated the efficacy and safety of ritlecitinib, an inhibitor of JAK3 and the tyrosine kinase expressed in hepatocellular carcinoma (TEC) kinase family, and brepocitinib, an inhibitor of tyrosine kinase 2 (TYK2)/JAK1 in the treatment of AA.

METHODS

Change in biomarkers in lesional scalp biopsy samples between baseline and weeks 12 and 24 was an exploratory end point, and 46 patients participated from the ritlecitinib (n = 18), brepocitinib (n = 16), and placebo (n = 12) groups. Correlations of biomarkers with hair regrowth, measured using the Severity of Alopecia Tool (SALT) score, were also evaluated.

CLINICAL TRIAL REGISTRATION

NCT02974868.

RESULTS

At week 24, both ritlecitinib and brepocitinib demonstrated improvement exceeding 100% in the lesional scalp transcriptome toward a nonlesional profile. At week 12, the improvements in scalp tissue were greater with brepocitinib than ritlecitinib; however, at week 24, the improvements were greater with ritlecitinib.

CONCLUSIONS

For both ritlecitinib and brepocitinib, improvement in the SALT scores was positively associated with expression of T_H1 markers and negatively associated with expression of hair keratins. Larger, long-term clinical trials are warranted.

The Pathology of Type 2 Inflammation-Associated Itch in Atopic Dermatitis

Accumulated evidence on type 2 inflammation-associated itch in atopic dermatitis has recently been reported. Crosstalk between the immune and nervous systems (neuroimmune interactions) is prominent in atopic dermatitis research, particularly regarding itch and inflammation. A comprehensive understanding of bidirectional neuroimmune interactions will provide insights into the pathogenesis of itch and its treatment. There is currently no agreed cure for itch in atopic dermatitis; however, increasing numbers of novel and targeted biologic agents have potential for its management and are in the advanced stages of clinical trials. In this review, we summarize and discuss advances in our understanding of type 2 inflammation-associated itch and implications for its management and treatment in patients with atopic dermatitis.

Advances in Atopic Dermatitis in 2019-2020: Endotypes from skin barrier, ethnicity, properties of antigen, cytokine profiles, microbiome, and engagement of immune cells

Key research advances in atopic dermatitis (AD) suggest the complexity of its endotypes. A comprehensive serum biomarker panel revealed at least four types of AD. Some represent classic TH2-dominant AD with filaggrin mutations commonly reported in Europeans, a simultaneously activated multipolar axes of cytokines often reported in Asians, and an intrinsic type characterized by TH2-inferiority. Innate lymphoid cells, including NK cells, NKT cells, and fibroblasts, play a role in AD development and heterogeneity. Here, we discuss the endotypes of AD from the perspective of antigen types (hapten vs. protein antigens), barrier function, and a novel set of immune cells. Endotypic stratification of AD may lead to the development of customized therapeutic strategies in the future.

Five Functional Aspects of the Epidermal Barrier

The epidermis is a living, multilayered barrier with five functional levels, including a physical, a chemical, a microbial, a neuronal, and an immune level. Altogether, this complex organ contributes to protect the host from external aggression and to preserve its integrity. In this review, we focused on the different functional aspects.

Sensitivity of clinician-assessed efficacy outcome measurement instruments in trials of topical therapies for atopic dermatitis: a systematic review and meta-analysis

The rising prevalence of atopic dermatitis (AD) in developing countries and its substantial socioeconomic impact have furthered research over the last two decades giving way to advances in its aetiopathogenesis and treatment. Topical therapies targeting newly identified AD signalling pathways are being developed. Numerous clinician-assessed disease severity outcome measurement instruments (OMIs) are available to evaluate the efficacy of investigational treatments in proof-of-concept (POC) trials for AD. However, little is known about the comparative sensitivity of these efficacy OMIs. We performed a systematic review and meta-analysis to compare the sensitivity of different OMIs in controlled trials of topical therapies for AD published between January 1, 2000 and April 7, 2020. Treatment effect size of OMIs reported at Week 4 was calculated with 95% Confidence Interval (CI). The sensitivity of OMIs was compared by pooling the standardized difference between means (Cohen's d and Cohen's h) for any two OMI-parameter combinations that were reported in ≥3 studies identified in our systematic review. Assessed parameters were difference between active and vehicle at Week 4 and change from baseline [CFB] and percentage change from baseline [%CFB] at Week 4. We identified a total of 15 studies with 3313 subjects examining 14 different OMIs were included in this quantitative meta-analysis. Continuous OMIs had a significantly higher treatment effect size vs. dichotomous OMIs (P = 0.006). Comparisons of Eczema Area and Severity Index (EASI), Investigator's Global Assessment (IGA), body surface area (BSA) and SCORing Atopic Dermatitis (SCORAD) for available parameters were performed and generally had a similar sensitivity, with BSA showing smaller overall effect size estimates. In conclusion, continuous OMIs used in topical clinical trials for AD had significantly higher treatment effect sizes when compared to dichotomous OMIs. Continuous OMIs could provide more power for POC trials with a small sample size in atopic dermatitis with topical therapies.

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.