Novel Therapeutic Targets for the Treatment of Atopic Dermatitis

Cure for the itch: current clinical standards and therapies in allergic eczema

Allergic Eczema (AE) is a chronic, relapsing skin condition that significantly affects the quality of life of the AE patients and their caretakers. Decades of scientific and clinical research has helped understand the highly complex underpinnings of AE presentation wherein a multitude of variables, including the conspicuous variables such as environmental allergens, immunological triggers, genetic predisposition of individuals, to more nuanced socio-economic status, play an important part. Given the complexity of the disease, it is imperative to develop biomarkers enabling early and reliable clinical identifications and help in the active management of the disease, thereby minimizing the impact and burden of the disease on the patients. In this mini review, we provide a brief overview of AE, affected demographics, variables that trigger its onset, and summarize the discovery of various clinical biomarkers such as total and specific serum IgE levels, Th2 cytokine levels, filaggrin (FLG) mutations, periostin levels in skin, etc. that have been developed over the years to further improve the state of clinical monitoring of AE presentation and progression. Lastly, we also provide an overview of the clinical interventions and therapies, such as topical agents, phototherapy, and biologics, that are available to the patients to manage AE-related complications. While we have vastly improved the standard of care and diagnosis for the AE patients, there are still many unmet needs such as developing non-invasive, effective, and reliable clinical predictors and biomarkers which can usher better personalized treatments and provide a better quality of life to affected demographics.

Cytokine profile of the stratum corneum in atopic dermatitis lesions differs between the face and the trunk

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease with intense pruritus. Dupilumab, an anti-IL-4 receptor alpha antibody, has been revealed to be highly effective against the symptoms of AD; however, dupilumab takes longer to improve facial dermatitis in some patients. We thus examined whether the cytokine profiles in AD lesions differ between different anatomical locations.

METHODS

Stratum corneum was collected by tape stripping from lesions of the forehead and abdomen of 24 patients with moderate to severe AD and at the same anatomical locations of 14 control subjects. These samples were then used to determine the expression profiles of Th1, Th2, and Th17 cytokines/chemokines by multiplex assay and immunocytochemistry.

RESULTS

We found that cytokines/chemokines in the stratum corneum differed in their expression between different anatomical areas in AD patients and also in healthy control subjects. The expression of Th1 and Th17 cytokines/chemokines such as IP-10, MIG, and IL-17 tended to be higher in the forehead than in the abdomen in the AD group. Regarding Th2 cytokines/chemokines, some (e.g., IL-13 and IL-33) were highly expressed in the abdomen, others (e.g., IL-4 and IL-31) were highly expressed in the forehead, and a third group (e.g., TARC and TSLP) did not differ significantly in their expression between the forehead and abdomen. These patterns of Th2 cytokines were almost identical in the stratum corneum of healthy individuals.

CONCLUSIONS

Differences in cytokine/chemokine profiles in the stratum corneum between different anatomical areas might affect the responsiveness to AD treatment.

An Overview of Atopic Dermatitis Disease Burden, Pathogenesis, and the Current Treatment Landscape: Recommendations for Appropriate Utilization of Systemic Therapies

Objective

To review the disease impact, immunopathogenesis, and treatment landscape of atopic dermatitis (AD), including recommendations for appropriate utilization of systemic treatments.

Methods

A PubMed search for relevant articles on AD and the treatment landscape was conducted using the key words "atopic dermatitis," "biologic," "therapeutic inertia," "Janus kinase (JAK) inhibitor," and "systemic treatment."

Results

AD is a common, chronic inflammatory skin disease that can have a profound negative impact on quality of life. With recent advancements and approvals of systemic treatments, it is now possible to offer targeted therapy to patients with moderate-to-severe AD. When topical treatments are no longer sufficient for managing AD, recently published AD management guidelines recommend that providers consider/offer advanced systemic treatments.

Limitations

More data are needed on the use of systemic treatments in special populations, including head-to-head comparisons of available systemic treatments in these populations.

Conclusion

An increased awareness of the immunopathogenesis, diagnosis, and treatment landscape of AD is needed amongst healthcare providers (HCPs). Special consideration of diagnosis and treatment options should be given to certain populations, including patients of different ages, those who may be pregnant or become pregnant, are biologic-experienced, and/or have comorbidities. Of note, HCPs should be aware of the clinical presentation in patients with skin of color. Therapeutic inertia can prevent HCPs from intensifying treatment when needed, and HCPs should know when it is appropriate to offer systemic treatments, including biologics and JAK inhibitors.

New Developments and Therapeutic Drug Monitoring Options in Costimulatory Blockade in Solid Organ Transplantation: A Systematic Critical Review

PURPOSE

In this review, the authors summarized the latest developments in costimulatory blockade to prevent rejection after solid organ transplantation (SOT) and discussed possibilities for future research and the need for therapeutic drug monitoring (TDM) of these agents.

METHODS

Studies about costimulatory blockers in SOT in humans or animal transplant models in the past decade (2014-2024) were systematically reviewed in PubMed, European Union clinical trials (EudraCT), and ClinicalTrials.gov .

RESULTS

Seventy-five registered clinical trials and 58 published articles were found on costimulation blockade of the CD28-CD80/86, CD40-CD40L, and OX40-OX40L pathways. Belatacept, an antagonist of the CD28-CD80/86 pathway, is the only approved costimulatory agent in SOT, hence accounting for most of the research. Other identified costimulatory blocking agents included abatacept and CD28 antagonists tegoprubart, dazodalibep, and TNX-1500. Although tegoprubart was unsuccessful in pancreas transplantation in nonhuman primates, trials in human kidney transplantation are underway. Dazodalibep trials faced recruitment challenges. TNX-1500 was unsuccessful in animal studies and is currently not pursued in humans. After discontinuation of iscalimab (CD40-CD154 pathway antagonist) in SOT, the alternatives, bleselumab and KPL404, showed promising results in kidney transplantation and cardiac xenotransplantation. Studies on secondary costimulatory pathway antagonists, such as OX40-OX40L, have only used animal models. Despite the low interindividual variability in pharmacokinetics (PK) in all studied agents, TDM could be useful for optimizing dosing in PK/pharmacodynamic (PD) studies.

CONCLUSIONS

The routine use of costimulation blockade in SOT is hindered by problems in efficacy compared with the standard of care. Costimulatory inhibitors could be combined in a calcineurin inhibitor-free regimen. Future PK/pharmacodynamic studies in costimulatory agents and personalized medicine could warrant TDM of these agents.

Research progress in OX40/OX40L in allergic diseases

OX40/OX40L are costimulatory molecules in the tumor necrosis factor superfamily. Numerous studies have shown that OX40/OX40L are involved in immune regulation, especially in the proliferation and differentiation of T cells and the generation of memory T cells, which play important roles in allergic diseases. In recent years, the use of OX40/OX40L as therapeutic targets for treating T-cell-mediated diseases has attracted the interest of scholars. This paper reviews the role of OX40/OX40L in allergic diseases and the progress in clinical treatments targeting this signaling pathway.

Patients' preferences for systemic treatment of atopic dermatitis: safety and efficacy count the most

BACKGROUND

The advent of biologics and janus kinase inhibitors has revolutionized treatment of atopic dermatitis (AD).

OBJECTIVE

To investigate preferences of patients with AD for attributes of currently approved systemic treatments and assess influencing factors.

METHODS

An online discrete choice experiment was conducted in patients with AD throughout Germany to analyze preferences for outcome (probability of (almost) clear skin at week 16, probability of significant itch improvement, time to onset of itch relief and type of side effects) and process attributes (application method and frequency of laboratory tests).

RESULTS

Participants (n = 182, 75.3% female) considered side effects (Relative Importance Score (RIS): 31.2), (almost) clear skin (RIS: 24.2) and probability of itch improvement (RIS: 16.0) most important. Application method (RIS: 14.4), time to onset of itch relief (RIS: 7.4) and frequency of laboratory tests (RIS: 6.8) were less relevant. Preferences were significantly influenced by sex, age, psychiatric comorbidity, current therapy and health-related quality of life according to multivariate regression analysis.

CONCLUSIONS

Participants attached great importance to safety and symptom control. However, preferences were also dependent on individual characteristics, underscoring the importance of personal counseling. Conjoined with medical considerations, patients' preferences have fundamental impact on shared decisions for treatment of AD.

Extracellular ATP Contributes to Barrier Function and Inflammation in Atopic Dermatitis: Potential for Topical Treatment of Atopic Dermatitis by Targeting Extracellular ATP

Atopic dermatitis (AD) is characterized by chronic inflammation, barrier dysfunction, and pruritus, exacerbated by external stimuli, such as scratching. This study investigates the role of extracellular adenosine triphosphate (ATP) in the pathophysiology of AD and assesses the therapeutic potential of clodronate, an ATP release inhibitor. Our research demonstrates that extracellular ATP impairs skin barrier function by reducing the filaggrin expression in the keratinocytes, a critical protein for barrier integrity. Furthermore, ATP release, triggered by IL-4 and mechanical stimuli, amplifies inflammation by promoting cytokine and chemokine production by the immune cells. Clodronate, by inhibiting ATP release, restores the filaggrin levels in the keratinocytes, reduces TARC production in the dendritic cells, and alleviates AD symptoms in a mouse model. These findings suggest that targeting extracellular ATP could offer a novel therapeutic approach to improving skin barrier function and reducing inflammation in AD. Future studies should explore the long-term efficacy and safety of ATP-targeted therapies in clinical settings.

Novel therapeutic receptor agonists and antagonists in allergic conjunctivitis

PURPOSE OF REVIEW

Allergic conjunctivitis is characterized by the development of pathophysiological changes to the ocular surface, which occurs when pro-allergic and pro-inflammatory mediators interact with their cognate receptors expressed on immune and nonimmune cells. Traditional treatments with antihistamines and corticosteroids provide relief, but there is a need for more efficacious and tolerable long-term therapy with a better safety profile. This article aims to provide an overview of the mode of action and clinical application of agonist therapies targeting glucocorticoid, melanocortin, and toll-like receptors, as well as antagonist therapies targeting cytokine, chemokine, integrin, and histamine receptors.

RECENT FINDINGS

There has been considerable advancement in immunology and pharmacology, as well as a greater understanding of the cellular and molecular mechanisms of allergic conjunctivitis. Recent research advancing therapy for allergic conjunctivitis has focused on developing synthetic molecules and biologics that can interfere with the process of the allergic immune reaction.

SUMMARY

This review discusses novel therapeutic receptors being explored agonistically or antagonistically to develop alternative treatment options for allergic conjunctivitis. These novel approaches hold promise for improving the management of allergic eye diseases, offering patients hope for more effective and safer treatment options in the future.

Mast Cell-Targeting Therapies in Mast Cell Activation Syndromes

PURPOSE OF REVIEW

Provide an overview of the expanding landscape of mast cell (MC)-targeting treatments in mast cell activation syndromes (MCAS).

RECENT FINDINGS

Tyrosine-kinase inhibitors (TKIs) targeting wild-type and mutated KIT can efficiently induce MC depletion. Avapritinib and midostaurin can also temper IgE-mediated degranulation. Avapritinib has been recently approved by the FDA for the treatment of indolent systemic mastocytosis (ISM). Targeting activation pathways and inhibitory receptors is a promising therapeutic frontier. Recently, the anti Siglec-8 antibody lirentelimab showed promising results in ISM. MCAS is a heterogeneous disorder demanding a personalized therapeutic approach and, especially when presenting as anaphylaxis, has not been formally captured as outcome in prospective clinical trials with TKI. Long-term safety of TKI needs to be addressed. New drugs under investigation in diseases in which non-neoplastic MCs play a pivotal role can provide important inputs to identify new efficient and safe treatments for MCAS.

cAMP-PKA/EPAC signaling and cancer: the interplay in tumor microenvironment

Cancer is a complex disease resulting from abnormal cell growth that is induced by a number of genetic and environmental factors. The tumor microenvironment (TME), which involves extracellular matrix, cancer-associated fibroblasts (CAF), tumor-infiltrating immune cells and angiogenesis, plays a critical role in tumor progression. Cyclic adenosine monophosphate (cAMP) is a second messenger that has pleiotropic effects on the TME. The downstream effectors of cAMP include cAMP-dependent protein kinase (PKA), exchange protein activated by cAMP (EPAC) and ion channels. While cAMP can activate PKA or EPAC and promote cancer cell growth, it can also inhibit cell proliferation and survival in context- and cancer type-dependent manner. Tumor-associated stromal cells, such as CAF and immune cells, can release cytokines and growth factors that either stimulate or inhibit cAMP production within the TME. Recent studies have shown that targeting cAMP signaling in the TME has therapeutic benefits in cancer. Small-molecule agents that inhibit adenylate cyclase and PKA have been shown to inhibit tumor growth. In addition, cAMP-elevating agents, such as forskolin, can not only induce cancer cell death, but also directly inhibit cell proliferation in some cancer types. In this review, we summarize current understanding of cAMP signaling in cancer biology and immunology and discuss the basis for its context-dependent dual role in oncogenesis. Understanding the precise mechanisms by which cAMP and the TME interact in cancer will be critical for the development of effective therapies. Future studies aimed at investigating the cAMP-cancer axis and its regulation in the TME may provide new insights into the underlying mechanisms of tumorigenesis and lead to the development of novel therapeutic strategies.

Basophils in pruritic skin diseases

Basophils are rare cells in the peripheral blood which have the capability to infiltrate into the skin. Invasion of basophils has been detected in pruritic skin diseases, including atopic dermatitis, bullous pemphigoid, chronic spontaneous urticaria and contact dermatitis. In the skin, basophils are important players of the inflammatory immune response, as they release Th2 cytokines, including interleukin (IL)-4 and IL-13, subsequently inducing the early activation of T-cells. Further, basophils release a multitude of mediators, such as histamine and IL-31, which both play an important role in the initiation of the pruritic response via activation of sensory nerves. Chronic pruritus significantly affects the quality of life and the working capability of patients, though its mechanisms are not fully elucidated yet. Since basophils and neurons share many receptors and channels, bidirectional interaction mechanisms, which drive the sensation of itch, are highlighted in this review.