The role of OX40L/OX40 axis signalling in atopic dermatitis.

Atopic dermatitis (AD) is a heterogeneous inflammatory condition involving multiple immune pathways mediated by pathogenic T cells. OX40 Ligand (OX40L) and OX40 are co-stimulatory immune checkpoint molecules that regulate effector and memory T cell activity and promote sustained immune responses in multiple immunological pathways, including Th2, Th1, Th17 and Th22. As such, OX40L/OX40 signalling between antigen-presenting cells (APCs) and activated T cells post-antigen recognition promotes pathogenic T cell proliferation and survival. Under inflammatory conditions, OX40L is upregulated on APCs, enhancing the magnitude of antigen-specific T cell responses and secretion of proinflammatory cytokines. In AD, OX40L/OX40 signalling contributes to the amplification and chronic persistence of T-cell mediated inflammation. Recent therapeutic success in clinical trials has highlighted the importance of the OX40L/OX40 axis as a promising target for the treatment of AD. Here we discuss the many factors that are involved in the expression of OX40L and OX40, including the cytokine milieu, antigen presentation, the inflammatory environment in AD, and the therapeutic direction influenced by this co-stimulatory pathway.

Monoclonal antibodies for moderate-to-severe atopic dermatitis: a look at phase III and beyond.

INTRODUCTION: The understanding of atopic dermatitis (AD) pathogenesis has rapidly expanded in recent years, catalyzing the development of new targeted monoclonal antibody treatments for AD. AREAS COVERED: This review aims to summarize the latest clinical and molecular data about monoclonal antibodies that are in later stages of development for AD, either in Phase 3 trials or in the pharmacopoeia for up to 5 years, highlighting the biologic underpinning of each drug's mechanism of action and the potential modulation of the AD immune profile. EXPERT OPINION: The therapeutic pipeline of AD treatments is speedily progressing, introducing the potential for a personalized medicine approach in the near future. Understanding how targeting pathogenic players in AD modifies disease progression and symptomatology is key in improving therapeutic choices for patients and identifying ideal patient candidates.

A Review of Atomic-Force Microscopy in Skin Barrier Function Assessment.

Skin barrier function (SBF) disorders are a class of pathologies that affect a significant portion of the world population. These disorders cause skin lesions with intense itch, impacting patients' physical and psychological well-being as well as their social functioning. It is in the interest of patients that their disorder be monitored closely while under treatment to evaluate the effectiveness of the ongoing therapy and any potential adverse reactions. Symptom-based assessment techniques are widely used by clinicians; however, they carry some limitations. Techniques to assess skin barrier impairment are critical for understanding the nature of the disease and for helping personalize treatment. This review recalls the anatomy of the skin barrier and describes an atomic-force microscopy approach to quantitatively monitor its disorders and their response to treatment. We review a panel of studies that show that this technique is highly relevant for SBF disorder research, and we aim to motivate its adoption into clinical settings.

Integrated Safety Update of Abrocitinib in 3802 Patients with Moderate-to-Severe Atopic Dermatitis: Data from More than 5200 Patient-Years with Up to 4 Years of Exposure.

BACKGROUND: Abrocitinib, an oral, once-daily, Janus kinase 1-selective inhibitor, is efficacious in moderate-to-severe atopic dermatitis with a manageable long-term safety profile. OBJECTIVE: We aimed to provide updated integrated long-term safety results for abrocitinib from available data accrued up to a maximum of almost 4 years in patients with moderate-to-severe atopic dermatitis from the JADE clinical development program. METHODS: Analysis included 3802 patients (exposure: 5213.9 patient-years) from the phase II monotherapy study (NCT02780167) and the phase III studies JADE MONO-1 (NCT03349060), JADE MONO-2 (NCT03575871), JADE TEEN (NCT03796676), JADE COMPARE (NCT03720470), JADE DARE (NCT04345367; 200 mg only), JADE REGIMEN (NCT03627767), and JADE EXTEND (NCT03422822; data cutoff 25 September, 2021). Data from patients receiving one or more doses of abrocitinib 200 mg or 100 mg were pooled in a consistent-dose cohort (patients were allocated to receive the same abrocitinib dose throughout exposure in the qualifying parent study and/or long-term study) or a variable-dose cohort (patients received open-label abrocitinib 200 mg; responders were randomized to abrocitinib 200 mg, 100 mg, or placebo, and could then receive abrocitinib 200 mg plus topical corticosteroids as rescue therapy). Incidence rates of adverse events of special interest were assessed. Cox regression analysis of risk factors for herpes zoster and serious infections was performed. RESULTS: Overall, this safety analysis of long-term data up to a maximum of ~ 4 years of abrocitinib exposure does not indicate any changes from the previously reported risk profile. The most frequent serious infections (per Medical Dictionary for Regulatory Activities preferred term) with consistent-dose abrocitinib 200 mg and 100 mg were herpes zoster (0.5% and 0.2%), pneumonia (0.2% with either dose), and herpes simplex (0.1% with either dose). Risk factors for herpes zoster were a history of herpes zoster, abrocitinib 200-mg dose, age ≥ 65 years, absolute lymphocyte count < 1 × 103/mm3 before the event, and residing in Asia. For serious infections, > 100 kg body weight was a risk factor. Incidence rate/100 patient-years (95% confidence interval) with the consistent abrocitinib 200-mg and 100-mg dose combined was higher in older (aged ≥ 65 years) patients versus younger (aged 18 to < 65 years) patients for serious adverse events (17.6 [11.7‒25.4] vs 6.7 [5.8‒7.8]), malignancy excluding non-melanoma skin cancer (2.4 [0.6‒6.0] vs 0.1 [0.0‒0.4]), non-melanoma skin cancer (2.4 [0.6‒6.1] vs 0.2 [0.1‒0.4]), lymphopenia (3.5 [1.3‒7.6] vs 0.1 [0.0‒0.3]), and venous thromboembolism (1.7 [0.4‒5.1] vs 0.1 [0.0‒0.3]). Incident rate/100 patient-years (95% confidence interval) of non-melanoma skin cancer with the consistent abrocitinib 200-mg and 100-mg dose combined was higher in current/former smokers (0.9 [0.4‒1.6]) vs never-smokers (0.0 [0.0‒0.1]). CONCLUSIONS: This safety update showed a consistent profile for abrocitinib with no new safety signals and continues to support that abrocitinib has a manageable long-term safety profile in patients with moderate-to-severe atopic dermatitis. Risk of specific adverse events was higher in certain patient populations, especially those aged ≥ 65 years. [Video abstract available.] CLINICAL TRIAL REGISTRATION: NCT02780167; study start date: April, 2016; primary completion date: March, 2017; study completion date: April, 2017. NCT03349060; study start date: 7 December, 2017; study completion date: 26 March, 2019. NCT03575871; study start date: 29 June, 2018; study completion date: 13 August, 2019. NCT03720470; study start date: 29 October, 2018; primary completion date: 27 December, 2019; study completion date: 6 March, 2020. NCT03796676; study start date: 18 February, 2019; study completion date: 8 April, 2020. NCT03627767; study start date: 11 June, 2018; primary completion date: 2 September, 2020; study completion date: 7 October, 2020. NCT04345367; study start date: 11 June, 2020; primary completion date: 16 December, 2020; study completion date: 13 July, 2021. NCT03422822; study start date: 8 March, 2018; study completion date: ongoing (estimated completion date: 31 January, 2026).

Abrocitinib is an approved treatment for people with moderate or severe atopic dermatitis, also known as AD or atopic eczema. Abrocitinib is a tablet that is taken by mouth once a day. This safety analysis looked at the side effects of treatment in a large group of adults and adolescents with moderate or severe AD who took abrocitinib up to a maximum of almost 4 years. This analysis also looked at which people were more likely to have certain side effects after taking abrocitinib. The results from this analysis were similar to those of previous safety analyses with abrocitinib, with no new side effects. Infections such as shingles, pneumonia, or herpes simplex can occur during treatment with abrocitinib. Shingles was more likely to occur in people who previously had shingles before taking abrocitinib, or who took the higher dose of abrocitinib (200 mg), or were 65 years of age or older, or had certain blood test results, or lived in Asia. People who are 65 years of age or older and took abrocitinib were more likely to develop some types of cancer, have certain abnormal blood test results, or develop blood clots in the veins than people with AD who were younger and took abrocitinib. Current or former smokers with AD who took abrocitinib were more likely to develop skin cancer (but not melanoma) than people with AD who took abrocitinib but have never smoked. This analysis further shows that abrocitinib had manageable safety in patients with moderate-to-severe AD. Video abstract: Integrated safety update of abrocitinib in 3802 patients with moderate-to-severe atopic dermatitis: data from more than 5200 patient-years with up to 4 years of exposure (MP4 63720 KB).

Treating moderate-to-severe atopic dermatitis with benralizumab: results from the HILLIER study, a plain language summary.

WHAT IS THIS SUMMARY ABOUT?: Atopic dermatitis (AD) is a chronic (long-lasting) skin disease that leads to dry, itchy, and swollen red spots, which can also be painful and flare up at any time. Some people with AD have a high number of eosinophils, a type of white blood cell, which are associated with worse disease. Medicated creams and lotions, prescribed by health care providers, are meant to reduce the symptoms of AD. For some people, these creams and lotions do not work. Benralizumab injection is a medication that reduces and removes eosinophils. A clinical trial called HILLER tested benralizumab to see if there was a difference in symptoms of AD after reducing or removing eosinophils. This article explains how benralizumab reduced eosinophils and the effect it had on AD symptoms in the HILLIER study. WHAT WERE THE MAIN CONCLUSIONS REPORTED BY THE RESEARCHERS?: Benralizumab reduced blood eosinophil numbers. However, benralizumab showed no evidence of treatment benefit on signs, symptoms, or severity of AD, as measured by three skin assessments compared with placebo. Benralizumab was well tolerated and had a safety profile that was consistent with previous studies. The five most commonly reported side effects were COVID-19 infection, upper respiratory tract infection, headache, swelling of the lymph nodes, and pink eye (conjunctivitis) in patients who received either benralizumab or placebo. WHAT ARE THE KEY TAKEAWAYS?: Benralizumab lowered the number of blood eosinophils without improving AD symptoms and was well tolerated.

Mapping the immune cell landscape of severe atopic dermatitis by single-cell RNA-seq.

BACKGROUND: Efforts to profile atopic dermatitis (AD) tissues have intensified, yet comprehensive analysis of systemic immune landscapes in severe AD remains crucial. METHODS: Employing single-cell RNA sequencing, we analyzed over 300,000 peripheral blood mononuclear cells from 12 severe AD patients (Eczema area and severity index (EASI) > 21) and six healthy controls. RESULTS: Results revealed significant immune cell shifts in AD patients, including increased Th2 cell abundance, reduced NK cell clusters with compromised cytotoxicity, and correlated Type 2 innate lymphoid cell proportions with disease severity. Moreover, unique monocyte clusters reflecting activated innate immunity emerged in very severe AD (EASI > 30). While overall dendritic cells (DCs) counts decreased, a distinct Th2-priming subset termed "Th2_DC" correlated strongly with disease severity, validated across skin tissue data, and flow cytometry with additional independent severe AD samples. Beyond the recognized role of Th2 adaptive immunity, our findings highlight significant innate immune cell alterations in severe AD, implicating their roles in disease pathogenesis and therapeutic potentials. CONCLUSION: Apart from the widely recognized role of Th2 adaptive immunity in AD pathogenesis, alterations in innate immune cells and impaired cytotoxic cells have also been observed in severe AD. The impact of these alterations on disease pathogenesis and the effectiveness of potential therapeutic targets requires further investigation.

Beyond Avoidance: Advanced Therapies for Contact Dermatitis.

Contact dermatitis (CD) is a common and burdensome condition divided into irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD). Treatment relies on accurate diagnosis and identification of the trigger, as definitive treatment is irritant/allergen avoidance. However, avoidance is not always possible, such as if the patient is reacting to a necessary medical device, if the trigger is integral to the patient's occupation, or if avoidance is practically untenable. In these cases, treatment is particularly challenging, especially as the literature on treatments in this clinical scenario is limited. Additionally, CD has a complex pathophysiology that varies according to trigger type, leading to variable treatment efficacy. This article reviews the current literature on treatments for CD with a focus on treatments when trigger avoidance is not feasible.

Proteomic alterations in patients with atopic dermatitis.

INTRODUCTION: Atopic Dermatitis (AD) is the most common inflammatory skin disease with a complex and multifactorial pathogenesis. The use of proteomics in understanding AD has yielded the discovery of novel biomarkers and may further expand therapeutic options. AREAS COVERED: This review summarizes the most recent proteomic studies and the methodologies used in AD. It describes novel biomarkers that may monitor disease course and therapeutic response. The review also highlights skin and blood biomarkers characterizing different AD phenotypes and differentiates AD from other inflammatory skin disorders. A literature search was conducted by querying Scopus, Google Scholar, Pubmed/Medline, and Clinicaltrials.gov up to June 2023. EXPERT OPINION: The integration of proteomics into research efforts in atopic dermatitis has broadened our understanding of the molecular profile of AD through the discovery of new biomarkers. In addition, proteomics may contribute to the development of targeted treatments ultimately improving personalized medicine. An increasing number of studies are utilizing proteomics to explore this heterogeneous disease.

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.

Targeting IL-13 with tralokinumab normalizes type 2 inflammation in atopic dermatitis both early and at 2 years.

BACKGROUND: Tralokinumab is a monoclonal antibody that specifically neutralizes interleukin (IL)-13, a key driver of skin inflammation and barrier abnormalities in atopic dermatitis (AD). This study evaluated early and 2-year impacts of IL-13 neutralization on skin and serum biomarkers following tralokinumab treatment in adults with moderate-to-severe AD. METHODS: Skin biopsies and blood samples were evaluated from a subset of patients enrolled in the Phase 3 ECZTRA 1 (NCT03131648) and the long-term extension ECZTEND (NCT03587805) trials. Gene expression was assessed by RNA sequencing; protein expression was assessed by immunohistochemistry and immunoassay. RESULTS: Tralokinumab improved the transcriptomic profile of lesional skin by Week 4. Mean improvements in the expression of genes dysregulated in AD were 39% at Week 16 and 85% at 2 years with tralokinumab, with 15% worsening at Week 16 with placebo. At Week 16, tralokinumab significantly decreased type 2 serum biomarkers (CCL17/TARC, periostin, and IgE), reduced epidermal thickness versus placebo, and increased loricrin coverage versus baseline. Two years of tralokinumab treatment significantly reduced expression of genes in the Th2 (IL4R, IL31, CCL17, and CCL26), Th1 (IFNG), and Th17/Th22 (IL22, S100A7, S100A8, and S100A9) pathways as well as increased expression of epidermal differentiation and barrier genes (CLDN1 and LOR). Tralokinumab also shifted atherosclerosis signaling pathway genes (SELE, IL-37, and S100A8) toward non-lesional expression. CONCLUSION: Tralokinumab treatment improved epidermal pathology, reduced systemic markers of type 2 inflammation, and shifted expression of key AD biomarkers in skin towards non-lesional levels, further highlighting the key role of IL-13 in the pathogenesis of AD. CLINICAL TRIAL REGISTRATION: NCT03131648, NCT03587805.

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.

Transcriptomic evaluation of skin tape-strips in children with allergic asthma uncovers epidermal barrier dysfunction and asthma-associated biomarkers abnormalities.

INTRODUCTION: Tape-strips, a minimally invasive method validated for the evaluation of several skin diseases, may help identify asthma-specific biomarkers in the skin of children with allergic asthma. METHODS: Skin tape-strips were obtained and analyzed with RNA-Seq from children with moderate allergic asthma (MAA) (n = 11, mean age 7.00; SD = 1.67), severe allergic asthma (SAA) (n = 9, mean age 9.11; SD = 2.37), and healthy controls (HCs) (n = 12, mean age 7.36; SD = 2.03). Differentially expressed genes (DEGs) were identified by fold change ≥2 with a false discovery rate <0.05. Transcriptomic biomarkers were analyzed for their accuracy in distinguishing asthma from HCs, their relationships with asthma-related outcomes (exacerbation rate, lung function-FEV1, IOS-R5-20, and lung inflammation-FeNO), and their links to skin (barrier and immune response) and lung (remodeling, metabolism, aging) pathogenetic pathways. RESULTS: RNA-Seq captured 1113 in MAA and 2117 DEGs in SAA. Epidermal transcriptomic biomarkers for terminal differentiation (FLG/filaggrin), cell adhesion (CDH19, JAM2), lipid biosynthesis/metabolism (ACOT2, LOXL2) were significantly downregulated. Gene set variation analysis revealed enrichment of Th1/IFNγ pathways (p < .01). MAA and SAA shared downregulation of G-protein-coupled receptor (OR4A16, TAS1R3), upregulation of TGF-ß/ErbB signaling-related (ACVR1B, EGFR, ID1/2), and upregulation of mitochondrial-related (HIGD2A, VDAC3, NDUFB9) genes. Skin transcriptomic biomarkers correlated with the annualized exacerbation rate and with lung function parameters. A two-gene classifier (TSSC4-FAM212B) was able to differentiate asthma from HCs with 100% accuracy. CONCLUSION: Tape-strips detected epithelial barrier and asthma-associated signatures in normal-appearing skin from children with allergic asthma and may serve as an alternative to invasive approaches for evaluating asthma endotypes.

OX40 in the Pathogenesis of Atopic Dermatitis-A New Therapeutic Target.

Atopic dermatitis (AD) is a chronic, heterogeneous, inflammatory disease characterized by skin lesions, pruritus, and pain. Patients with moderate-to-severe AD experience chronic symptoms, intensified by unpredictable flares, and often have comorbidities and secondary complications, which can result in significant clinical burden that impacts the patient's overall quality of life. The complex interplay of immune dysregulation and skin barrier disruption drives AD pathogenesis, of which T-cell-dependent inflammation plays a critical role in patients with AD. Despite new targeted therapies, many patients with moderate-to-severe AD fail to achieve or sustain their individual treatment goals and/or may not be suitable for or tolerate these therapies. There remains a need for a novel, efficacious, well-tolerated therapeutic option that can deliver durable benefits across a heterogeneous AD patient population. Expression of OX40 [tumor necrosis factor receptor superfamily, member 4 (TNFRSF4)], a prominent T-cell co-stimulatory molecule, and its ligand [OX40L; tumor necrosis factor superfamily, member 4 (TNFSF4)] is increased in AD. As the OX40 pathway is critical for expansion, differentiation, and survival of effector and memory T cells, its targeting might be a promising therapeutic approach to provide sustained inhibition of pathogenic T cells and associated inflammation and broad disease control. Antibodies against OX40 [rocatinlimab (AMG 451/KHK4083) and telazorlimab (GBR 830)] or OX40L [amlitelimab (KY1005)] have shown promising results in early-phase clinical studies of moderate-to-severe AD, highlighting the importance of OX40 signaling as a new therapeutic target in AD.

Regulatory T-cell dysfunction and cutaneous exposure to Staphylococcus aureus underlie eczema in DOCK8 deficiency.

BACKGROUND: Dedicator of cytokinesis 8 (DOCK8)-deficient patients have severe eczema, elevated IgE, and eosinophilia, features of atopic dermatitis (AD). OBJECTIVE: We sought to understand the mechanisms of eczema in DOCK8 deficiency. METHODS: Skin biopsy samples were characterized by histology, immunofluorescence microscopy, and gene expression. Skin barrier function was measured by transepidermal water loss. Allergic skin inflammation was elicited in mice by epicutaneous sensitization with ovalbumin (OVA) or cutaneous application of Staphylococcus aureus. RESULTS: Skin lesions of DOCK8-deficient patients exhibited type 2 inflammation, and the patients' skin was colonized by Saureus, as in AD. Unlike in AD, DOCK8-deficient patients had a reduced FOXP3:CD4 ratio in their skin lesions, and their skin barrier function was intrinsically intact. Dock8-/- mice exhibited reduced numbers of cutaneous T regulatory (Treg) cells and a normal skin barrier. Dock8-/- and mice with an inducible Dock8 deletion in Treg cells exhibited increased allergic skin inflammation after epicutaneous sensitization with OVA. DOCK8 was shown to be important for Treg cell stability at sites of allergic inflammation and for the generation, survival, and suppressive activity of inducible Treg cells. Adoptive transfer of wild-type, but not DOCK8-deficient, OVA-specific, inducible Treg cells suppressed allergic inflammation in OVA-sensitized skin of Dock8-/- mice. These mice developed severe allergic skin inflammation and elevated serum IgE levels after topical exposure to Saureus. Both were attenuated after adoptive transfer of WT but not DOCK8-deficient Treg cells. CONCLUSION: Treg cell dysfunction increases susceptibility to allergic skin inflammation in DOCK8 deficiency and synergizes with cutaneous exposure to Saureus to drive eczema in DOCK8 deficiency.

Summary of Research: An Anti-OX40 Antibody to Treat Moderate-to-Severe Atopic Dermatitis: A Multicentre, Double-Blind, Placebo-Controlled Phase 2b Study.

This is a summary of the original article "An Anti-OX40 Antibody to Treat Moderate-to-Severe Atopic Dermatitis: a Multicentre, Double-blind, Placebo-Controlled Phase 2b Study". Atopic dermatitis (AD) is an inflammatory skin disease caused by a complex interplay of genetic factors, alterations to the skin microenvironment, and immune dysregulation, including T cells that have become uncontrolled. Rocatinlimab is an investigational agent that blocks OX40, a receptor on activated T cells that has an important role in inflammatory conditions such as AD. This summary of research provides an overview of a previously published article on the results of a phase 2b study of patients with moderate-to-severe AD who were treated with different doses of rocatinlimab or placebo and followed for up to 56 weeks. Rocatinlimab significantly improved the symptoms of AD and was well tolerated. The most common adverse events were fever, nasopharyngitis, and chills. This study supports rocatinlimab as a potentially safe and effective treatment for moderate-to-severe AD.