Improving evaluation of drugs in atopic dermatitis by combining clinical and molecular measures

Biomarkers for phenotype-endotype relationship in atopic dermatitis: a critical review

Atopic dermatitis (AD) is the most common form of chronic skin inflammation with diverse clinical variants. Historically, various AD phenotypes have been grouped together without considering their heterogeneity. This approach has resulted in a lack of phenotype- and endotype-adapted therapeutic strategies. Comprehensive insights into AD pathogenesis have enabled precise medicinal approach for AD. These efforts aimed to redefine the endophenotype of AD and develop various biomarkers for diverse purposes. Among these endeavours, efforts are underway to elucidate the mechanisms (and related biomarkers) that lead to the emergence and progression of atopic diseases originating from AD (e.g., atopic march). This review focuses on diverse AD phenotypes and calls for a definition of endophenotypes. While awaiting scientific validation, these biomarkers ensure predicting disease onset and trajectory and tailoring therapeutic strategies for the future.

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

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

Atopic dermatitis stratification: current and future perspective on skin and blood transcriptomic and proteomic profiling

INTRODUCTION

Atopic dermatitis (AD) is a common, chronic inflammatory skin disorder driven by an intricate interplay of genetic, environmental, and immunological factors.

AREAS COVERED

As a clinically heterogenous condition, AD may be stratified into subtypes based on factors including, chronicity, immunoglobulin E levels, severity, age, and ethnicity. Transcriptomic and proteomic analyses in skin and blood help elucidate the underlying molecular mechanisms of these AD subtypes, referred to as AD endotypes. Further characterizing AD endotypes using reliable biomarkers can facilitate the development of more effective and personalized therapeutics and improve our tools for monitoring disease progression and therapeutic response across a diverse subset of patients. Here, we aim to provide perspective on the latest research regarding AD stratification using skin and blood-based studies and insight into the implications of these findings on the future of AD research and clinical practice.

EXPERT OPINION

The precise stratification of AD endotypes will allow for the development of reliable biomarkers and a more personalized medical treatment approach. Clinical practice and trials will eventually be able to bridge clinical with molecular data to optimize individualized treatments and more effectively monitor treatment response.

Diversity of atopic dermatitis and selection of immune targets

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

Efficacy and Safety of Dupilumab in Patients With Erythrodermic Atopic Dermatitis: A Post Hoc Analysis of 6 Randomized Clinical Trials

Importance

Erythrodermic atopic dermatitis (AD) is a severe AD subtype defined by extensive skin involvement, leading to complications and sometimes hospitalization.

Objective

To assess dupilumab's efficacy and safety in patients with erythrodermic AD in clinical trials.

Design, Setting, and Participants

This post hoc analysis included patients enrolled in 6 multicenter, multinational, randomized, double-blind, placebo-controlled trials. Patients included in this analysis met erythrodermic AD criteria of 90% or greater body surface area (BSA) affected by AD and Global Individual Sign Score for erythema of 1 or higher. Data analyses for this post hoc analysis were conducted between March 5, 2019, and October 24, 2020.

Interventions

Dupilumab once weekly or every 2 weeks, or placebo, either as monotherapy or with concomitant topical corticosteroids (TCS).

Main Outcomes and Measures

Efficacy (BSA, Eczema Area and Severity Index [EASI] score, Peak Pruritus Numerical Rating Scale [PP-NRS] score), changes in serum biomarkers (thymus and activation-regulated chemokine, total immunoglobulin E, lactate dehydrogenase), and safety (incidence of adverse events) at week 16. Data were pooled within each regimen; monotherapy and concomitant TCS results are shown separately.

Results

Of 3075 randomized patients, 209 met criteria for erythrodermic AD at baseline, with the median age being 31 and 39 years in the monotherapy and concomitant TCS trials, respectively, similar to the overall populations (34 and 36 years, respectively); 71.3% (n = 97) and 74.0% (n = 54) of patients, respectively, were male (compared with 58.7% and 60.6% in the overall populations). In patients with erythrodermic AD, dupilumab once weekly and every 2 weeks vs placebo significantly improved percentage of BSA affected by AD (least squares mean percent change [SE]) with monotherapy (-42.0% [7.7%] and -39.9% [6.5%] vs -17.2% [11.0%]; P = .03) and concomitant TCS (-63.2% [6.7%] and -56.1% [9.1%] vs -14.5% [7.3%]; P < .001); EASI score with monotherapy (-58.5% [9.0%] and -58.3% [7.9%] vs -22.3% [12.4%]; P = .004 and P = .003, respectively) and concomitant TCS (-78.9% [7.8%] and -70.6% [10.1%] vs 19.3% [8.2%]; P < .001); and PP-NRS score in monotherapy (-45.9% [7.8%] and -33.9% [6.6%] vs -0.6% [9.4%]; P < .001) and concomitant therapy (-53.0% [8.1%] and -55.7% [10.8%] vs -26.0% [8.8%]; P = .006 and P = .01, respectively). Nominally statistically significant improvement was seen as early as week 1 (EASI and PP-NRS scores with monotherapy). Biomarker levels were significantly reduced vs placebo. The most frequent adverse events in dupilumab-treated patients were injection-site reaction, conjunctivitis, and nasopharyngitis.

Conclusions and Relevance

In this post hoc analysis of 6 randomized clinical trials, treatment with dupilumab resulted in rapid, sustained improvements in AD signs and symptoms with acceptable safety in patients with erythrodermic AD, similar to those in the trials' overall patient population.

Trial Registration

ClinicalTrials.gov Identifiers: NCT01859988, NCT02277743, NCT02277769, NCT03054428, NCT02260986, NCT02755649.

Biomarkers in atopic dermatitis

Atopic dermatitis (AD) is a complex and highly heterogeneous inflammatory skin disease. Given the highly heterogeneous character of AD, it is unlikely that every patient will respond equally to a particular treatment. The recent introduction of novel targeted therapies for AD has driven the need for patient stratification based on immunologic biomarkers. We have reviewed the use of different types of biomarkers as potential tools in the movement toward personalized medicine in AD, comprising different ways of endotyping patients with AD based on immunologic profiles and predictive biomarkers. The application of biomarkers will result in better characterization and stratification of patients and allow better comparison of current and new treatments. The ultimate goal will be to switch from the current generalized "one-drug-fits-all" management to more personalized "patient endotype-specific" management.

Baseline skin cytokine profiles determined by RNA in situ hybridization correlate with response to dupilumab in patients with eczematous dermatitis

BACKGROUND

Dupilumab has revolutionized the treatment of atopic dermatitis. However, not all patients respond optimally, and this may relate to underlying molecular heterogeneity. Nevertheless, clinically useful and accessible methods to assess such heterogeneity have not been developed.

OBJECTIVE

We assessed whether cytokine staining and/or histologic features correlate with clinical response to dupilumab in patients with eczematous dermatitis.

METHODS

We retrospectively analyzed biopsies from 61 patients with eczematous dermatitis treated with dupilumab (90.2% met Hanifin-Rajka criteria for atopic dermatitis). RNA in situ hybridization was used to measure markers of type 2 (interleukin [IL]4, IL13), type 1 (interferon gamma) and type 3 (IL17A, IL17F, IL22) inflammation. Histologic features were also assessed. Patterns were compared among complete (n = 16), partial (n = 37), and nonresponders (n = 8) to dupilumab.

RESULTS

We found that increased IL13 expression was associated with optimal response to dupilumab. In contrast, nonresponders tended to express less IL13 and relatively greater levels of type 1 and 3 cytokines. In addition, certain histologic features tended to correlate with improved response to dupilumab.

LIMITATIONS

Retrospective approach and small size of the nonresponder group.

CONCLUSION

Cytokine RNA in situ hybridization may aid in treatment selection for eczematous disorders. Moreover, personalization of treatment selection for inflammatory skin diseases may be possible.

Biomarkers associated with the development of comorbidities in patients with atopic dermatitis: A systematic review

Biomarkers associated with the development of comorbidities in atopic dermatitis (AD) patients have been reported, but have not yet been systematically reviewed. Seven electronic databases were searched, from database inception to September 2021. English language randomized controlled trials, prospective and retrospective cohort, and case-control studies that investigated the association between a biomarker and the development of comorbidities in AD patients were included. Two authors independently screened the records for eligibility, one extracted all data, and critically appraised the quality of studies and risk of bias. Fifty six articles met the inclusion criteria, evaluating 146 candidate biomarkers. The most frequently reported biomarkers were filaggrin mutations and allergen specific-IgE. Promising biomarkers include specific-IgE and/or skin prick tests predicting the development of asthma, and genetic polymorphisms predicting the occurrence of eczema herpeticum. The identified studies and biomarkers were highly heterogeneous, and associated with predominately moderate-to-high risk of bias across multiple domains. Overall, findings were inconsistent. High-quality studies assessing biomarkers associated with the development of comorbidities in people with AD are lacking. Harmonized datasets and independent validation studies are urgently needed.

Atopic Dermatitis: Striving for Reliable Biomarkers

Atopic dermatitis (AD) is a highly heterogeneous inflammatory disease regarding both its pathophysiology and clinical manifestations. However, it is treated according to the “one-size-fits-all” approach, which may restrict response to treatment. Thus, there is an unmet need for the stratification of patients with AD into distinct endotypes and clinical phenotypes based on biomarkers that will contribute to the development of precision medicine in AD. The development of reliable biomarkers that may distinguish which patients with AD are most likely to benefit from specific targeted therapies is a complex procedure and to date none of the identified candidate biomarkers for AD has been validated for use in routine clinical practice. Reliable biomarkers in AD are expected to improve diagnosis, evaluate disease severity, predict the course of disease, the development of comorbidities, or the therapeutic response, resulting in effective and personalized treatment of AD. Among the studied AD potential biomarkers, thymus and activation-regulated chemokine/C-C motif ligand 17 (TARC/CCL17) has the greatest evidence-based support for becoming a reliable biomarker in AD correlated with disease severity in both children and adults. In this review, we present the most prominent candidate biomarkers in AD and their suggested use.

Pharmacokinetics, Safety, Efficacy, and Biomarker Profiles During Nemolizumab Treatment of Atopic Dermatitis in Adolescents

Introduction

Nemolizumab, a new monoclonal antibody that targets the receptor alpha of the neuroimmune cytokine interleukin-31 (IL-31), has shown efficacy in atopic dermatitis (AD) in adults. This study evaluated the pharmacokinetics (PK) and safety of nemolizumab in adolescents with moderate to severe AD as well as the relationship between nemolizumab concentrations and clinical efficacy and the effect of nemolizumab on protein biomarkers.

Methods

Open-label, 16-week study of nemolizumab in patients aged 12–17 years with moderate to severe AD (baseline EASI ≥ 16, IGA ≥ 3, and BSA ≥ 10%) and associated pruritus with baseline average daily peak pruritus numeric rating scale (PP-NRS) intensity of at least 4. Nemolizumab was administered subcutaneously as a loading dose of 60 mg at baseline, followed by 30 mg every 4 weeks until week 12 with background topical corticosteroids (TCS) or calcineurin inhibitors (TCI). Subsequently patients were followed for 8 weeks more. Stratum corneum (SC) and plasma samples were collected for biomarker assessments.

Results

Twenty patients participated, with a mean age of 14.8 ± 1.6 years. The PK of nemolizumab was described by a one-compartment model with linear elimination, a first-order absorption, and a mean half-life of 16.7 ± 4.1 days. Mean trough concentrations ranged from 2935 ± 1029 ng/mL to 3292 ± 2018 ng/mL over the 16-week treatment period. There was a marked improvement in rash, itch, and sleep with a decrease from baseline to week 16 in EASI by 66.5 ± 32.5%, in PP-NRS by 43.2 ± 37%, and in sleep disturbance numeric rating scale by 53.5 ± 47.8%. The popPK and PK/PD analyses confirmed that model-predicted exposure and efficacy of nemolizumab were similar in adolescents compared to adults receiving the same dosing regimens. Age did not impact PK parameters, while the main source of PK variability was body weight. Analyses of SC samples identified a panel of AD-related pro-inflammatory biomarkers that were upregulated in lesional skin (compared to non-lesional skin) and correspondingly downregulated in clinical responders to nemolizumab (based on EASI75 and PP-NRS ≥ 4). Four biomarkers (CCL20, CCL22, CCL27, and VEGF) had changes that were 1.9–3.5-fold higher in EASI responders than in EASI non-responders (all p < 0.05). Analysis showed no significant correlation between plasma biomarkers and clinical scores. Adverse events were experienced by 33.3% of subjects (n = 6) and were primarily mild or moderate in severity.

Conclusions

Nemolizumab PK and safety profiles in adolescents with moderate to severe AD are consistent with previous nemolizumab studies in adults. PK/PD models demonstrate similar exposure–response profiles in 12- to 17-year-old adolescents and adults for three clinical endpoints (EASI, IGA, and PP-NRS). Nemolizumab treatment reversed AD-related pro-inflammatory biomarkers in skin, indicating that the neuroimmune cytokine IL-31 is an important mediator of multiple pathways in AD.

Clinical Trial Registration

Clinicaltrials.gov NCT03921411.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-021-00678-7.

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

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

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

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

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

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