The first trial of CIM331, a humanized antihuman interleukin-31 receptor A antibody, in healthy volunteers and patients with atopic dermatitis to evaluate safety, tolerability and pharmacokinetics of a single dose in a randomized, double-blind, placebo-controlled study

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.

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 medical 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.

Emerging drugs for the treatment of atopic dermatitis: a focus on phase 2 and phase 3 trials

INTRODUCTION

Atopic dermatitis (AD) is an inflammatory skin condition that affects millions of pediatric and adult patients with well-studied impact on morbidity and quality of life. Management occurs in a stepwise fashion beginning with preventative measures before immunomodulators are introduced. However, challenges remain in treatment of moderate-to-severe atopic dermatitis that is refractory to first- and second-line treatments and there are only few topical anti-inflammatory options, especially for pediatric patients.

AREAS COVERED

New medications are required to address these gaps as lesions may persist despite treatment or patients may discontinue treatment due to actual or anticipated adverse effects of mainstay medications. Emerging research into the pathophysiology of AD and the immune system at large has provided opportunities for novel interventions aimed at stopping AD mechanisms at new checkpoints. Clinical trials for 36 agents currently in phase 2 or phase 3 are evaluated with particular focus on the studies for, B244, CBP-201, tapinarof, lebrikizumab, nemolizumab, amlitelimab, and rocatinlimab as they explore novel pathways and have some of the most promising results.

EXPERT OPINION

These clinical trials contribute to the evolution of AD treatment toward greater precision based on salient pathways with a particular focus on moderate-to-severe AD to enhance efficacy and minimize adverse effects.

Efficacy and safety of nemolizumab in paediatric patients aged 6-12 years with atopic dermatitis with moderate-to-severe pruritus: results from a phase III, randomized, double-blind, placebo-controlled, multicentre study

BACKGROUND

Atopic dermatitis (AD) is a chronic, inflammatory skin condition affecting up to one-quarter of children. Uncontrolled pruritus associated with childhood AD, and the accompanying scratching, negatively impacts quality of life (QoL), sleep and development. The humanized monoclonal antibody nemolizumab, used concomitantly with topical agents, was shown to reduce pruritus and improve QoL in patients with AD aged ≥ 13 years. However, data relating to its efficacy and safety in younger children (aged < 13 years) have been lacking.

OBJECTIVES

To evaluate the efficacy and safety of nemolizumab, administered concomitantly with topical agents, in Japanese paediatric patients (aged 6-12 years) with AD and inadequately controlled moderate-to-severe pruritus.

METHODS

This was a randomized, placebo-controlled, double-blind, parallel-group, multicentre, 16-week, phase III study. Patients aged ≥ 6 and < 13 years, with confirmed AD, and an inadequate pruritic response despite treatment with topical agents and oral antihistamines were randomly assigned (1 : 1) to receive nemolizumab 30 mg or placebo every 4 weeks (Q4W). The primary efficacy endpoint was the change in the weekly mean 5-level itch score from baseline to week 16; secondary efficacy endpoints were related to pruritus, indicators for AD and QoL. Safety was assessed via adverse events (AEs) and laboratory test results.

RESULTS

In total, 89 patients were enrolled, received either nemolizumab 30 mg (n = 45) or placebo (n = 44) Q4W, and completed the study. The mean patient age was 9.1 (SD 1.9) years, and mean duration of AD was 8.5 (2.7) years. The change in 5-level itch score from baseline to week 16 showed a statistically significant difference in the nemolizumab treatment group (-1.3) compared with placebo (-0.5; least-squares mean difference -0.8, 95% confidence interval -1.1 to -0.5; P < 0.0001). Improvements with nemolizumab were observed from the second day of administration. Secondary endpoints were in favour of nemolizumab. No AEs resulted in discontinuation, and the overall safety profile in patients aged 6-12 years was comparable with that in older patients (aged ≥ 13 years) with AD.

CONCLUSIONS

Nemolizumab is a potential new treatment option for paediatric patients with AD whose pruritus has not been sufficiently improved with topical treatments and antihistamines.

Systemic treatments for atopic dermatitis (eczema): Systematic review and network meta-analysis of randomized trials

BACKGROUND

Atopic dermatitis (AD) is an inflammatory skin condition with multiple systemic treatments and uncertainty regarding their comparative impact on AD outcomes.

OBJECTIVE

We sought to systematically synthesize the benefits and harms of AD systemic treatments.

METHODS

For the 2023 American Academy of Allergy, Asthma & Immunology and American College of Allergy, Asthma, and Immunology Joint Task Force on Practice Parameters AD guidelines, we searched MEDLINE, EMBASE, CENTRAL, Web of Science, and GREAT databases from inception to November 29, 2022, for randomized trials addressing systemic treatments and phototherapy for AD. Paired reviewers independently screened records, extracted data, and assessed risk of bias. Random-effects network meta-analyses addressed AD severity, itch, sleep, AD-related quality of life, flares, and harms. The Grading of Recommendations Assessment, Development and Evaluation approach informed certainty of evidence ratings. This review is registered in the Open Science Framework (https://osf.io/e5sna).

RESULTS

The 149 included trials (28,686 patients with moderate-to-severe AD) evaluated 75 interventions. With high-certainty evidence, high-dose upadacitinib was among the most effective for 5 of 6 patient-important outcomes; high-dose abrocitinib and low-dose upadacitinib were among the most effective for 2 outcomes. These Janus kinase inhibitors were among the most harmful in increasing adverse events. With high-certainty evidence, dupilumab, lebrikizumab, and tralokinumab were of intermediate effectiveness and among the safest, modestly increasing conjunctivitis. Low-dose baricitinib was among the least effective. Efficacy and safety of azathioprine, oral corticosteroids, cyclosporine, methotrexate, mycophenolate, phototherapy, and many novel agents are less certain.

CONCLUSIONS

Among individuals with moderate-to-severe AD, high-certainty evidence demonstrates that high-dose upadacitinib is among the most effective in addressing multiple patient-important outcomes, but also is among the most harmful. High-dose abrocitinib and low-dose upadacitinib are effective, but also among the most harmful. Dupilumab, lebrikizumab, and tralokinumab are of intermediate effectiveness and have favorable safety.

Canine interleukin-31 binds directly to OSMRβ with higher binding affinity than to IL-31RA

Interleukin-31 (IL-31) is a pro-inflammatory cytokine involved in skin inflammation and tumor progression. The IL-31 signaling cascade is initiated by its binding to two receptors, IL-31 receptor alpha (IL-31RA) and oncostatin M receptor subunit beta (OSMRβ). The previous study suggested that human IL-31 (hIL-31) directly interacts with IL-31RA and OSMRβ, independently, but the binding ability of hIL-31 to IL-31RA is stronger than to OSMRβ. In different to its human ortholog, feline IL-31 (fIL-31) has a higher binding affinity for feline OSMRβ. However, the binding pattern of canine IL-31 to its receptors remains to be elucidated. In this study, we purified the recombinant canine IL-31 (rcIL-31) protein and revealed its secondary structure to be mainly composed of alpha-helices. Moreover, in vitro studies show that rcIL-31 has the ability to induce the phosphorylation of signal transducer activator of transcription 3 (STAT3) and STAT5 in DH-82 cells. In the following, the binding efficacies of bioactive rcIL-31 for its individual receptor components have been measured using a flow cytometry assay. The result demonstrates that correctly refolded rcIL-31 binds independently with cIL-31RA and cOSMRβ which were expressed on the cell surface. Of note, rcIL-31 has a greater than tenfold higher affinity to OSMRβ than to IL-31RA. Additionally, we demonstrated that D1-D4, especially D4 of cOSMRβ, is crucial for its binding to cIL-31. Furthermore, this study proved that rcIL-31 has a high binding affinity to the soluble cOSMRβ with a KD value of 3.59 × 10-8 M. The results presented in the current study will have a significant implication in the development of drugs or antibodies against diseases induced by cIL-31 signaling.

The immunological and structural epidermal barrier dysfunction and skin microbiome in atopic dermatitis-an update

Atopic dermatitis (AD) is a common, chronic and relapsing inflammatory skin disease with various clinical presentations and combinations of symptoms. The pathophysiology of AD is complex and multifactorial. There are several factors involved in the etiopathogenesis of AD including structural and immunological epidermal barrier defect, imbalance of the skin microbiome, genetic background and environmental factors. Alterations in structural proteins, lipids, proteases, and their inhibitors, lead to the impairment of the stratum corneum which is associated with the increased skin penetration and transepidermal water loss. The elevated serum immunoglobulin E levels and blood eosinophilia have been shown in the majority of AD patients. Type 2 T-helper cell immune pathway with increased expression of interleukin (IL)-4, IL-5, and IL-13, has an important role in the etiopathogenesis of AD. Both T cells and keratinocytes contribute to epidermal barrier impairment in AD via a dynamic interaction of cytokines and chemokines. The skin microbiome is another factor of relevance in the etiopathogenesis of AD. It has been shown that during AD flares, Staphylococcus aureus (S. aureus) colonization increased, while Staphylococcus epidermidis (S. epidermidis) decreased. On the contrary, S. epidermidis and species of Streptococcus, Corynebacterium and Propionibacterium increased during the remision phases. However, it is not clear whether skin dysbiosis is one of the symptoms or one of the causes of AD. There are several therapeutic options, targeting these pathways which play a critical role in the etiopathogenesis of AD. Although topical steroids are the mainstay of the treatment of AD, new biological therapies including IL-4, IL-13, and IL-31 inhibitors, as well as Janus kinase inhibitors (JAKi), increasingly gain more importance with new advances in the therapy of AD. In this review, we summarize the role of immunological and structural epidermal barrier dysfunction, immune abnormalities, impairment of lipids, filaggrin mutation and skin microbiome in the etiopathogenesis of AD, as well as the therapeutic options for AD and their effects on these abnormalities in AD skin.

Nemolizumab Improves Patient-Reported Symptoms of Atopic Dermatitis with Pruritus: Post Hoc Analysis of a Japanese Phase III Randomized Controlled Trial

INTRODUCTION

Atopic dermatitis (AD), with its signs and symptoms of pruritus, dryness, and erythema, severely reduces the quality of life (QOL) of affected patients. We investigated the impact of nemolizumab 60 mg on QOL in Japanese patients aged ≥ 13 years with AD and inadequately controlled moderate-to-severe pruritus, using data derived from patient-reported outcome (PRO) measures.

METHODS

PROs were the Insomnia Severity Index (ISI), Dermatology Life Quality Index (DLQI), Patient-Oriented Eczema Measure (POEM), and Work Productivity and Activity Impairment: Atopic Dermatitis questionnaire (WPAI-AD). Correlations between PRO scores and symptom severity, assessed by the pruritus visual analog scale (VAS) and the Eczema Area and Severity Index (EASI), were explored.

RESULTS

The mean percent change (standard error) from baseline in the pruritus VAS and EASI scores at week 16 was, respectively, -45.6% (2.7) and -46.0% (3.2) in the nemolizumab group, and -24.1% (3.7) and -33.2% (4.9) in the placebo group. By week 16, significantly more patients in the nemolizumab group versus the placebo group had an ISI score of 0 for difficulty falling asleep (41.6% versus 13.1%, nominal p < 0.01) or difficulty staying asleep (45.4% versus 10.9%; nominal p < 0.01). Similarly, more nemolizumab- than placebo-treated patients had a DLQI score of 0 for interference with shopping, or home/garden activities (45.2% versus 18.6%, nominal p < 0.01), and 0 days per week of nighttime sleep disturbance (50.8% versus 16.9%, nominal p < 0.01) or bleeding skin (43.4% versus 7.5%, nominal p < 0.01) measured by POEM at week 16. Based on WPAI-AD scores, long-term administration of nemolizumab also improved the ability to conduct work activities.

CONCLUSIONS

Subcutaneous administration of nemolizumab ameliorated pruritus and skin signs, and thereby produced improvement in patient QOL across multiple PRO measures, including sleep, interpersonal relationships, and the ability to conduct social or work activities.

CLINICAL TRIAL REGISTRATION

JapicCTI-173740 (registered 20 October 2017).

Clinically meaningful improvements in cutaneous lesions and quality of life measures in patients with atopic dermatitis with greater pruritus reductions after treatment with 60 mg nemolizumab subcutaneously every 4 weeks: Subgroup analysis from a phase 3, randomized, controlled trial

BACKGROUND

Data from the Japanese phase 3 Nemolizumab-JP01 study (JapicCTI-173740) found that nemolizumab in combination with topical treatments reduced pruritus associated with atopic dermatitis inadequately controlled with current therapies.

METHODS

This post-hoc analysis examined associations between improvements in pruritus (visual analog scale [VAS]) and eczema (Eczema Area and Severity Index [EASI]), and achievement of other clinically relevant endpoints including the Insomnia Severity Index (ISI), Dermatology Life Quality Index (DLQI), and Patient-Oriented Eczema Measure (POEM).

RESULTS

Pruritus VAS responders (≥50% improvement from baseline to week 16) showed greater improvements from baseline in these additional endpoints as early as week 1, compared with non-responders. Responders also had EASI improvement, and more than 80% achieved an ISI score ≤7, or had improvement in the DLQI or POEM. The percent change from baseline in VAS and EASI scores at week 16 was in favor of nemolizumab in all subgroups based on baseline characteristics. No specific factor affecting treatment response to nemolizumab was identified.

CONCLUSIONS

In this post-hoc analysis, nemolizumab-treated patients who had greater pruritus reductions also showed improvements in other eczema symptoms; pruritus alleviation appeared to be responsible for the improvements in eczema, sleep and daily life.

Blockage of the IL-31 Pathway as a Potential Target Therapy for Atopic Dermatitis

Atopic dermatitis (AD), a pruritic, inflammatory chronic disease with multifactorial pathogenesis, has been a therapeutic challenge. Novel target treatments aim to reduce not only the immunologic dysfunction and microbiome dysbiosis but also the recovery of the damaged skin barrier. The current review focuses on the interleukin 31 (IL-31) pathway and AD and offers an overview of the current clinical studies with monoclonal antibodies blocking this cascade. Pruritus, the key symptom of AD, has substantial participation of the IL-31 complex and activation of relevant signaling pathways. Epidermal keratinocytes, inflammatory cells, and cutaneous peripheral nerves express the interleukin-31 receptor α-chain (IL-31RA), upregulated by Staphylococcus aureus toxins or Th2 cytokines involved in AD. Nemolizumab is a humanized monoclonal antibody that antagonizes IL-31RA, inhibiting the IL-31 cascade and therefore contributing to reducing the pruritus and inflammation and recovering the damaged skin barrier in AD patients. Phases 2 and 3 clinical trials with nemolizumab in AD show a suitable safety profile, with a fast, efficient, and sustained reduction of pruritus and severity scores, especially when associated with topical treatment. Deciphering the full interplay of the IL-31 pathway and AD may expand the potential of nemolizumab as a targeted therapy for AD and other pruritic conditions.

Neural Regulation of Innate Immunity in Inflammatory Skin Diseases

As the largest barrier organ of the body, the skin is highly innervated by peripheral sensory neurons. The major function of these sensory neurons is to transmit sensations of temperature, pain, and itch to elicit protective responses. Inflammatory skin diseases are triggered by the aberrant activation of immune responses. Recently, increasing evidence has shown that the skin peripheral nervous system also acts as a regulator of immune responses, particularly innate immunity, in various skin inflammatory processes. Meanwhile, immune cells in the skin can express receptors that respond to neuropeptides/neurotransmitters, leading to crosstalk between the immune system and nervous system. Herein, we highlight recent advances of such bidirectional neuroimmune interactions in certain inflammatory skin conditions.

Immunotherapy in atopic dermatitis

In the past decade, the emergence of biologics targeting human cytokine networks has advanced a new era in atopic dermatitis therapy. Dupilumab, in particular, the most widely studied and used IL-4/IL-13 inhibitor, has been considered a milestone in the treatment of patients with moderate-to-severe atopic dermatitis. In addition to the IL-4 and IL-13 pathways, many other cytokines and receptors have been newly targeted as therapeutic options. In this review, the authors provide an overview of the approved and tested biologics and JAK inhibitors for the treatment of atopic dermatitis, including their advantages and limitations.

IL-31: State of the Art for an Inflammation-Oriented Interleukin

Interleukin 31 belongs to the IL-6 superfamily, and it is an itch mediator already studied in several diseases, comprising atopic dermatitis, allergic pathologies, and onco-hematological conditions. This research aims to assess the role of this cytokine in the pathogenesis of these conditions and its potential therapeutic role. The research has been conducted on articles, excluding reviews and meta-analysis, both on animals and humans. The results showed that IL-31 plays a crucial role in the pathogenesis of systemic skin manifestations, prognosis, and itch severity. Traditional therapies target this interleukin indirectly, but monoclonal antibodies (Mab) directed against it have shown efficacy and safety profiles comparable with biological drugs that are already available. Future perspectives could include the development of new antibodies against IL-31 both for humans and animals, thus adding a new approach to the therapy, which often has proven to be prolonged and specific for each patient.

Cytokines and chemokines modulation of itch

Itch (pruritus) is a common cutaneous symptom widely associated with many skin complaints, and chronic itch can be a severe clinical problem. The onset and perpetuation of itch are linked to cytokines, such as interleukin (IL)-31, IL-4, IL-13, IL-33, thymic stromal lymphopoietin, and tumor necrosis factor-alpha, and chemokines, such as chemokine (C-C motif) ligand 2 and C-X-C motif chemokine ligand 10. This review highlights research that has attempted to determine the attributes of various cytokines and chemokines concerning the development and modulation of itch. Through such research, clinical approaches targeting cytokines and/or chemokines may arise, which may further the development of itch therapeutics.

Safety and Efficacy of Nemolizumab for Atopic Dermatitis With Pruritus: A Systematic Review and Meta-Regression Analysis of Randomized Controlled Trials

Background

Nemolizumab is deemed as a promising drug for atopic dermatitis (AD) patients with pruritus.

Objective

This study aimed to evaluate the efficacy of nemolizumab in treating patients with AD and the association between the dosage or regimen of nemolizumab with the improvement in clinical indices.

Methods and Materials

PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials (RCTs) published from inception to August 2021.

Results

A total of 14 cohorts of participants from six randomized controlled studies were included in the meta-analysis. Nemolizumab significantly reduced the pruritus VAS (WMD = -18.86, 95% CI: -27.57 to -10.15, p < 0.001; I ² = 56.2%, p _{heterogeneity} = 0.005) and EASI (WMD = -11.76, 95% CI: -20.55 to -2.96, p = 0.009; I ² = 0%, p _{heterogeneity} = 0.978) scores compared with placebo. No significant difference was observed in the occurrence of any AEs (RR = 1.03, 95% CI: 0.93 to 1.13, p = 0.593; I ² = 0%, p _{heterogeneity} = 0.980) between the two groups. The univariate meta-regression showed that both the dosage and study duration had no association with the change of pruritus VAS score.

Conclusion

Nemolizumab presented a promising effect based on the difference in the average change in pruritus VAS and EASI scores compared with placebo. The results indicated its efficacy in relieving pruritus and the severity of AD and improving patients' quality of life.

Targeting therapeutic approaches and highlighting the potential role of nanotechnology in atopic dermatitis

Atopic dermatitis is a chronic as well as widespread skin disease which has significant influence on the life attributes of affected people and their families. Systemic immunosuppressive drugs can be utilised for effective care of disease, although they are often prescribed for rigorous disruption or disease that is complicated to manage. Therefore, topical applications of corticosteroids are considered the primary pharmacologic therapies for atopic dermatitis, and research recommends that these medications might be helpful in preventing disease flare-ups. However, topical medicine administration to deeper layers of skin is challenging because of the skin anatomic barrier that restricts deeper drug permeation, and also due to barrier function abnormalities in atopic dermatitis skin, which might result in systemic drug absorption, provoking systemic consequences. Hence, effective management of atopic dermatitis needs new, effective, safe and targeted treatments. Therefore, nanotechnology-based topical therapeutics have attracted much interest nowadays because of their tendency to increase drug diffusion and bioavailability along with enormous drug targeting potential to affected cells, and, thereby, reducing the adverse effects of medications. In this review, we mention different symptoms of atopic dermatitis, and provide an overview of the different triggering factors causing atopic dermatitis, with emphasis on its epidemiology, pathophysiology, clinical features and diagnostic, and preventive measures. This review discusses existing therapeutics for treating atopic dermatitis, and the newer approaches as well as the current classical pharmacotherapy of atopic dermatitis against new nanoparticle skin delivery systems. This review has also briefly summarised the recent patents and clinical status of therapeutic modalities for atopic dermatitis.

Neuro-immune communication regulating pruritus in atopic dermatitis

Atopic dermatitis (AD) is a common, chronic-relapsing inflammatory skin disease with significant disease burden. Genetic and environmental trigger factors contribute to AD, activating two of our largest organs, the nervous and immune system. Dysregulation of neuro-immune circuits plays a key role in the pathophysiology of AD causing inflammation, pruritus, pain, and barrier dysfunction. Sensory nerves can be activated by environmental or endogenous trigger factors transmitting itch stimuli to the brain. Upon stimulation, sensory nerve endings also release neuromediators into the skin contributing again to inflammation, barrier dysfunction and itch. Additionally, dysfunctional peripheral and central neuronal structures contribute to neuroinflammation, sensitization, nerve elongation, neuropathic itch, thus chronification and therapy-resistance. Consequently, neuro-immune circuits in skin and central nervous system may be targets to treat pruritus in AD. Cytokines, chemokines, proteases, lipids, opioids, ions excite/sensitize sensory nerve endings not only induce itch but further aggravate/perpetuate inflammation, skin barrier disruption, and pruritus. Thus, targeted therapies for neuro-immune circuits as well as pathway inhibitors (e.g., kinase inhibitors) may be beneficial to control pruritus in AD either in systemic and/or topical form. Understanding neuro-immune circuits and neuronal signaling will optimize our approach to control all pathological mechanisms in AD, inflammation, barrier dysfunction and pruritus.

Unravelling the pathophysiology of chronic kidney disease-associated pruritus

For decades, itch related to chronic kidney disease (CKDaP) has been a clinical problem, but the aetiology and pathophysiology of CKDaP are still not yet fully understood—currently the underlying pathophysiological mechanisms are thought to be multifactorial. As new therapeutic targets have recently been identified and clinical trials have shown promising results, our current understanding of the interrelationships has expanded significantly. Here we review the pathophysiology and recent findings on modulation and sensitization of itch contributing to the development of CKDaP, covering hypothesis regarding immune system dysfunction, metabolic changes, uremic toxin deposition, peripheral neuropathy and imbalances in the endogenous opioid system.

A New Era with the Development of Cytokine-Based Therapy for Pruritus

Pruritus is a common dermatological condition and negatively impacts QOL. Persistent pruritus and excessive scratching behavior can lead to the itch-scratch cycle that exacerbates inflammatory skin diseases. Conventional antipruritic drugs, such as antihistamines, corticosteroids, or anticonvulsants, are sometimes insufficient. Recently, however, molecularly targeted drugs, such as IL-31 or IL-4 receptor-targeting antibodies, have become available or are under clinical trials, dramatically changing the clinical situation. In fact, some of these drugs can improve pruritus without the need for topical steroids. Taken together, these observations point to the importance of cytokine-mediated pruritus, further understanding of which may guide improved therapies.

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.

Nemolizumab plus topical agents in patients with atopic dermatitis (AD) and moderate-to-severe pruritus provide improvement in pruritus and signs of AD for up to 68 weeks: results from two phase III, long-term studies

Background

Interleukin (IL)‐31 affects the inflammatory response, is involved in epidermal barrier disruption in atopic dermatitis (AD) and plays a key role in pruritus. Nemolizumab, a humanized monoclonal antibody against IL‐31 receptor A, reduced pruritus in patients with AD after a 16‐week administration period.

Objectives

To examine the long‐term effectiveness and safety of nemolizumab in patients aged ≥ 13 years with AD and inadequately controlled moderate‐to‐severe pruritus.

Methods

In two long‐term phase III studies, nemolizumab 60 mg every 4 weeks (Q4W) was administered subcutaneously, concomitantly with topical treatments. Study‐JP01 patients received double‐blind nemolizumab or placebo for 16 weeks, and then entered a 52‐week extension period in which all patients received nemolizumab (nemolizumab/nemolizumab and placebo/nemolizumab groups). Study‐JP02 patients received nemolizumab for 52 weeks. Both studies included an 8‐week follow‐up period.

Results

Study‐JP01 nemolizumab/nemolizumab and placebo/nemolizumab, and Study‐JP02 nemolizumab groups comprised 143, 72 and 88 patients, respectively. In the nemolizumab/nemolizumab group, there were clinically meaningful improvements from the start of treatment to week 68 in the pruritus visual analogue scale (66% decrease) and Eczema Area and Severity Index (78% decrease). Quality of life (QoL) indicators improved after the first nemolizumab dose; improvements were maintained during the follow‐up period. The long‐term safety profile was consistent with previous studies, with no unexpected late‐onset adverse events.

Conclusions

Nemolizumab 60 mg Q4W with concomitant topical treatments in patients with AD and inadequately controlled moderate‐to‐severe pruritus produced a continuous improvement in pruritus, signs of AD, and QoL for up to 68 weeks, with a favourable safety profile.

Significance of interleukin-31 (IL-31) gene polymorphisms and IL-31 serum level in psoriasis in correlation with pruritus

Introduction

Interleukin-31 (IL-31) impact on the development and clinical presentation of psoriasis as well as pruritus has not been widely investigated so far.

Aim

To analyse IL-31 -1066G/A and -2057G/A promoter gene polymorphisms as well as serum IL-31 level and their correlation with severity of psoriasis and pruritus in the population of northern Poland.

Material and methods

The study included 300 psoriasis patients and 186 healthy volunteers. The polymorphisms were analysed using amplified refractory mutation system - polymerase chain reaction (ARMS-PCR) method. Serum levels of IL-31 were measured using the enzyme-linked immunosorbent assay (ELISA) test.

Results

The -1066 AA genotype of the IL-31 gene was statistically more frequent in patients and it increased the risk of psoriasis (OR = 1.80; p = 0.04). The GG genotype as well as G allele of the IL-31 -2057 gene polymorphism were rarely observed in psoriasis and were associated with a decreased risk of the disease (OR = 0.6, p = 0.007 and OR = 0.7, p = 0.01, respectively). Serum levels of IL-31 were significantly elevated in psoriasis patients (p < 0.000001), however, they did not correlate with the studied polymorphic variants of the IL-31 gene, severity of psoriasis, disease onset, presence of psoriatic arthritis and pruritus intensity.

Conclusions

Distinct IL-31 promoter gene polymorphisms may be involved in psoriasis development. It seems that serum concentration of IL-31 may not be a reliable marker of psoriatic pruritus.

Interleukin-31: The "itchy" cytokine in inflammation and therapy

The cytokine interleukin-31 has been implicated in the pathophysiology of multiple atopic disorders such as atopic dermatitis (AD), allergic rhinitis, and airway hyper-reactivity. In AD, IL-31 has been identified as one of the main "drivers" of its cardinal symptom, pruritus. Here, we summarize the mechanisms by which IL-31 modulates inflammatory and allergic diseases. T_H 2 cells play a central role in AD and release high levels of T_H 2-associated cytokines including IL-31, thereby mediating inflammatory responses, initiating immunoregulatory circuits, stimulating itch, and neuronal outgrowth through activation of the heterodimeric receptor IL-31 receptor A (IL31RA)/Oncostatin M receptor (OSMRβ). IL31RA expression is found on human and murine dorsal root ganglia neurons, epithelial cells including keratinocytes and various innate immune cells. IL-31 is a critical cytokine involved in neuroimmune communication, which opens new avenues for cytokine modulation in neuroinflammatory diseases including AD/pruritus, as validated by recent clinical trials using an anti-IL-31 antibody. Accordingly, inhibition of IL-31-downstream signaling may be a beneficial approach for various inflammatory diseases including prurigo. However, as to whether downstream JAK inhibitors directly block IL-31-mediated-signaling needs to be clarified. Targeting the IL-31/IL31RA/OSMRβ axis appears to be a promising approach for inflammatory, neuroinflammatory, and pruritic disorders in the future.

The New Era of Biologics in Atopic Dermatitis: A Review

Atopic dermatitis (AD) is a prevalent inflammatory skin disorder affecting all age and ethnic groups. The age-dependent varying appearance and extent of pruritic lesions are accompanied by distinct individual suffering, highlighting the importance of effective treatment options. Over the past years systemic drugs have considerably extended therapeutic approaches of patients with moderate to severe AD, in particular new biologics, most notably dupilumab has appeared as major breakthrough. In addition to monoclonal blockade of IL-4 and IL-13 pathway, more cytokines have been found to play a substantial role in AD pathogenesis, presenting potential targets for new therapy options.

IL-31 and IL-8 in Cutaneous T-Cell Lymphoma: Looking for Their Role in Itch

The itch associated with cutaneous T-cell lymphoma (CTCL), including Mycosis Fungoides (MF) and Sézary syndrome (SS), is often severe and poorly responsive to treatment with antihistamines. Recent studies have highlighted the possible role of interleukins in nonhistaminergic itch. We investigated the role of IL-31 and IL-8 in CTCL, concerning disease severity and associated itch. Serum samples of 27 patients with CTCL (17 MF and 10 SS) and 29 controls (blood donors) were analyzed for interleukin- (IL-) 31 and IL-8; correlations with disease and itch severity were evaluated. IL-31 serum levels were higher in CTCL patients than in controls and higher in SS than in MF. Also, serum IL-31 levels were higher in patients with advanced disease compared to those with early disease, and they correlated positively with lactate dehydrogenase and beta 2-microglobulin levels, as well as with the Sézary cell count. Itch affected 67% of CTCL patients (MF: 47%; SS: 100%). Serum IL-31 levels were higher in itching patients than in controls and in patients without itching. There was no association between serum IL-8 and disease severity, nor with itching. Serum IL-8 levels correlated positively with peripheral blood leukocyte and neutrophil counts in CTCL patients. Our study suggests a role for IL-31 in CTCL-associated itch, especially in advanced disease and SS, offering a rational target for new therapeutic approaches. Increased serum IL-8 observed in some patients may be related to concomitant infections, and its role in exacerbating itch by recruiting neutrophils and promoting the release of neutrophil proteases deserves further investigation.

Th2 Modulation of Transient Receptor Potential Channels: An Unmet Therapeutic Intervention for Atopic Dermatitis

Atopic dermatitis (AD) is a multifaceted, chronic relapsing inflammatory skin disease that affects people of all ages. It is characterized by chronic eczema, constant pruritus, and severe discomfort. AD often progresses from mild annoyance to intractable pruritic inflammatory lesions associated with exacerbated skin sensitivity. The T helper-2 (Th2) response is mainly linked to the acute and subacute phase, whereas Th1 response has been associated in addition with the chronic phase. IL-17, IL-22, TSLP, and IL-31 also play a role in AD. Transient receptor potential (TRP) cation channels play a significant role in neuroinflammation, itch and pain, indicating neuroimmune circuits in AD. However, the Th2-driven cutaneous sensitization of TRP channels is underappreciated. Emerging findings suggest that critical Th2-related cytokines cause potentiation of TRP channels, thereby exaggerating inflammation and itch sensation. Evidence involves the following: (i) IL-13 enhances TRPV1 and TRPA1 transcription levels; (ii) IL-31 sensitizes TRPV1 via transcriptional and channel modulation, and indirectly modulates TRPV3 in keratinocytes; (iii) The Th2-cytokine TSLP increases TRPA1 synthesis in sensory neurons. These changes could be further enhanced by other Th2 cytokines, including IL-4, IL-25, and IL-33, which are inducers for IL-13, IL-31, or TSLP in skin. Taken together, this review highlights that Th2 cytokines potentiate TRP channels through diverse mechanisms under different inflammatory and pruritic conditions, and link this effect to distinct signaling cascades in AD. This review strengthens the notion that interrupting Th2-driven modulation of TRP channels will inhibit transition from acute to chronic AD, thereby aiding the development of effective therapeutics and treatment optimization.

IL-31, itch and hematological malignancies

Pruritus is one of the most common symptoms experienced by neoplastic patients. The pathogenesis of neoplastic itch is complex and multifactorial and could be due to an unbalanced production of humoral mediators by altered immune effector cells. IL-31 is a pro-inflammatory cytokine produced by CD4 + T helper cells. The aim of this review was to evaluate the role of this Th2 cytokine and its receptor IL-31RA, in the onset of neoplastic pruritus. We analysed scientific literature looking for the most relevant original articles linking IL-31to itch in oncologic diseases. Interleukin-31 seems to be a main itch mediator in several hematologic disease such as Cutaneous T cells lymphomas. In these patients IL-31 was positively linked to itch level, and IL-31 matched with disease stage. IL-31 seems to play an important role in the signalling pathway involved in pruritus, but it is also suggested to play a proinflammatory and immunomodulatory role which could play a part in the progression of the neoplastic disease. Further studies will be fundamental in facing pruritus in oncologic patients, since this problem compromise their quality of life worsening an already critic picture.

Innate Immune Regulation of Dermatitis

Dermatitis encompasses a spectrum of inflammatory skin disorders with aberrant immune responses classified as type 1, type 2, and/or type 3. Major advances in the understanding of the pathogenesis of atopic dermatitis (AD) have shed new light on how innate immune responses critically regulate type 2 inflammation and itch. This article highlights the diverse ways by which type 2 immune cells regulate diseases beyond AD. The discovery of human Mas-related G protein-coupled receptor X2 on mast cells has revealed novel T cell-independent and immunoglobulin E-independent mechanisms of allergic contact dermatitis-associated and urticarial itch, respectively.

New and Emerging Systemic Treatments for Atopic Dermatitis

Atopic dermatitis (AD) is a prevalent inflammatory skin condition that, depending on its severity, can cause enormous morbidity. Corticosteroids and systemic immunosuppression, traditionally standard of care for difficult-to-treat disease, have many undesirable side effects. The desire for targeted treatments along with an improved understanding of the pathophysiology of AD has spurred the development of novel treatments. In this article, we review promising new treatments and discuss how their targets—IL-13, IL-31, OX40 (CD134), and the Janus kinase family of proteins—participate in the pathogenesis of AD. We review the published phase II and III data for dupilumab, tralokinumab, lebrikizumab, nemolizumab, anti-OX40 antibody, baricitinib, abrocitinib, and upadacitinib. The introduction of new agents may offer new options, but it remains to be seen how narrow-acting agents, like single interleukin inhibitors, will compare in safety and efficacy to broad-acting agents such as JAK inhibitors.

Interleukin-31 and Pruritic Skin

Skin inflammation often evokes pruritus, which is the major subjective symptom in many inflammatory skin diseases such as atopic dermatitis and prurigo nodularis. Pruritus or itch is a specific sensation found only in the skin. Recent studies have stressed the pivotal role played by interleukin-31 (IL-31) in the sensation of pruritus. IL-31 is produced by various cells including T helper 2 cells, macrophages, dendritic cells and eosinophils. IL-31 signals via a heterodimeric receptor composed of IL-31 receptor A (IL-31RA) and oncostatin M receptor β. Recent clinical trials have shown that the anti-IL-31RA antibody nemolizumab can successfully decrease pruritus in patients with atopic dermatitis and prurigo nodularis. The IL-31 pathway and pruritic skin are highlighted in this review article.

IL-31 Inhibition as a Therapeutic Approach for the Management of Chronic Pruritic Dermatoses

Chronic pruritus is a debilitating symptom with limited treatment options. Identifying molecular targets underlying chronic pruritic dermatoses is essential for the development of novel, targeted therapies. IL-31 is an important mediator of itch by integrating dermatologic, neural, and immune systems. IL-31 helps induce and maintain chronic pruritus via both indirect stimulation of inflammatory cells and through direct neural sensitization. IL-31 is overexpressed in various chronic pruritic skin conditions, and exogenous IL-31 induces itch and scratching behavior. Studies have demonstrated that IL-31R and IL-31 antagonism significantly reduces itch in patients with atopic dermatitis and prurigo nodularis, two extremely pruritic skin conditions. Emerging evidence, including recent phase II clinical trials of IL-31R antagonists, demonstrates that IL-31 plays an important role in itch signaling. Additional studies are ongoing to evaluate IL-31R and IL-31 antagonism as treatments of chronic pruritus.

Bidirectional sensory neuron-immune interactions: a new vision in the understanding of allergic inflammation

Peripheral neurons (including sensory neurons) are ubiquitously distributed in all tissues, particularly at the interface with the environment. The primary function of sensory neurons is the transmission of sensations of temperature, pain and itch to elicit appropriate behavioral responses. More recently, sensory neurons have emerged as potent regulators of type 2 immune responses and allergic inflammation. There is increasing evidence showing that neurons can express receptors previously thought to be restricted to the immune compartment. In addition, certain subtypes of immune cells (e.g. mast cells, ILC2s or macrophages) also express specific neuroreceptors that provide them with the capacity to integrate neuron-derived signals and modulate their activation status during the development of allergic inflammation.

Anti-pruritic effect of nemolizumab in hemodialysis patients with uremic pruritus: a phase II, randomized, double-blind, placebo-controlled clinical study

BACKGROUND

The pathophysiology of uremic pruritus (UP), which is characterized by systemic and intractable itching, remains unclear. As interleukin (IL)-31 may be involved, we conducted a phase II, randomized, controlled study to evaluate nemolizumab (anti-IL-31 receptor A antibody) in Japanese hemodialysis patients with UP.

METHODS

Patients were randomly assigned (1:1:1:1:1) to one of four double-blind groups (receiving a single subcutaneous injection of nemolizumab 0.125, 0.5, or 2.0 mg/kg, or placebo on Day 1) or an open-label reference group (receiving oral nalfurafine hydrochloride 2.5-5 μg once daily for 12 weeks). The primary endpoint was the difference in the absolute change in pruritus visual analog scale (VAS) at Week 4 between placebo and each nemolizumab group.

RESULTS

The primary efficacy endpoint was not met. The mean change from baseline with all three nemolizumab doses at Week 1, and with 0.5 mg/kg at Week 4, was greater than with placebo. Least square mean differences (95% confidence intervals) in the absolute changes between the placebo arm and each nemolizumab arm were - 2.4 (- 19.7, 14.9) for 0.125 mg/kg, - 8.7 (- 26.6, 9.2) for 0.5 mg/kg, and 0.4 (- 17.0, 17.8) for 2.0 mg/kg. Secondary efficacy parameters including the Shiratori severity score and 5-D itch score failed to show between-group differences. Patients with higher serum IL-31 levels at screening tended to have greater pruritus VAS reductions following nemolizumab treatment.

CONCLUSIONS

In this phase II study in patients with UP, the primary efficacy parameter was not met. Nemolizumab was generally well tolerated with no clinically significant safety concerns.

CLINICAL TRIAL REGISTRATION

JAPIC: JapicCTI-152961, https://www.clinicaltrials.jp/cti-user/trial/ShowDirect.jsp?japicId=JapicCTI-152961 .

Intractable Itch in Atopic Dermatitis: Causes and Treatments

Itch or pruritus is the hallmark of atopic dermatitis and is defined as an unpleasant sensation that evokes the desire to scratch. It is also believed that itch is a signal of danger from various environmental factors or physiological abnormalities. Because histamine is a well-known substance inducing itch, H₁-antihistamines are the most frequently used drugs to treat pruritus. However, H₁-antihistamines are not fully effective against intractable itch in patients with atopic dermatitis. Given that intractable itch is a clinical problem that markedly decreases quality of life, its treatment in atopic dermatitis is of high importance. Histamine-independent itch may be elicited by various pruritogens, including proteases, cytokines, neuropeptides, lipids, and opioids, and their cognate receptors, such as protease-activated receptors, cytokine receptors, Mas-related G protein-coupled receptors, opioid receptors, and transient receptor potential channels. In addition, cutaneous hyperinnervation is partly involved in itch sensitization in the periphery. It is believed that dry skin is a key feature of intractable itch in atopic dermatitis. Treatment of the underlying conditions that cause itch is necessary to improve the quality of life of patients with atopic dermatitis. This review describes current insights into the pathophysiology of itch and its treatment in atopic dermatitis.

Involvement of Neuro-Immune Interactions in Pruritus With Special Focus on Receptor Expressions

Pruritus is a common, but very challenging symptom with a wide diversity of underlying causes like dermatological, systemic, neurological and psychiatric diseases. In dermatology, pruritus is the most frequent symptom both in its acute and chronic form (over 6 weeks in duration). Treatment of chronic pruritus often remains challenging. Affected patients who suffer from moderate to severe pruritus have a significantly reduced quality of life. The underlying physiology of pruritus is very complex, involving a diverse network of components in the skin including resident cells such as keratinocytes and sensory neurons as well as transiently infiltrating cells such as certain immune cells. Previous research has established that there is a significant crosstalk among the stratum corneum, nerve fibers and various immune cells, such as keratinocytes, T cells, basophils, eosinophils and mast cells. In this regard, interactions between receptors on cutaneous and spinal neurons or on different immune cells play an important role in the processing of signals which are important for the transmission of pruritus. In this review, we discuss the role of various receptors involved in pruritus and inflammation, such as TRPV1 and TRPA1, IL-31RA and OSMR, TSLPR, PAR-2, NK1R, H1R and H4R, MRGPRs as well as TrkA, with a focus on interaction between nerve fibers and different immune cells. Emerging evidence shows that neuro-immune interactions play a pivotal role in mediating pruritus-associated inflammatory skin diseases such as atopic dermatitis, psoriasis or chronic spontaneous urticaria. Targeting these bidirectional neuro-immune interactions and the involved pruritus-specific receptors is likely to contribute to novel insights into the underlying pathogenesis and targeted treatment options of pruritus.

Interleukin-31 as a Clinical Target for Pruritus Treatment

In recent years, the published literature has suggested the key involvement of the cytokine interleukin-31 (IL-31) in the symptomatology of pruritus, and both IL-31 and its receptor have become potential therapeutic targets for a range of pruritic diseases. Elevated levels of IL-31 or its receptor have been reported in the tissue or serum of patients with pruritic skin diseases, such as atopic dermatitis, prurigo nodularis, and psoriasis. Pruritus places a heavy burden on patients, and can have a negative impact on daily life, sleep, and mental health. Since current anti-pruritic treatments are often ineffective, affected patients are in urgent need of new therapies. As a result, drug development targeting the IL-31 pathway is evolving rapidly. To date, only nemolizumab, a humanized monoclonal antibody targeting the IL-31 receptor, has successfully completed late-stage clinical studies. This article will highlight our current clinical understanding of the role of IL-31 in pruritic disease, and explore recent progress in drug development as well as the anticipated future advances in this field.

Biologics for atopic diseases: Indication, side effect management, and new developments

With the advent of biologicals, more and more therapeutics are available that specifically address specific switch points in the pathomechanism of immunologically dominated diseases. Thus, the focus of diagnostics and therapy (precision medicine) is more on the individual disease characteristics of the individual patient. Regarding the different phenotypes of atopic diseases, severe asthma was the first entity for which biologicals were approved, followed by urticaria, and finally atopic dermatitis and chronic rhinosinusitis with nasal polyps. Experience in the treatment of severe bronchial asthma has shown that the intensity of the response to biological therapy depends on the quality of clinical and immunological phenotyping of the patients. This also applies to different diseases of the atopic form, as patients can suffer from several atopic diseases at the same time, each with different characteristics. Biologics are already emerging that may represent a suitable therapy for allergic bronchial asthma, which often occurs together with severe neurodermatitis, and chronic rhinosinusitis with nasal polyps. In practice, however, the question of possible combinations of biologicals for the therapy of complex clinical pictures of individual patients is increasingly arising. In doing so, the side effect profile must be taken into account, including hypersensitivity reactions, whose diagnostic and logistical management must aim at a safe and efficient therapy of the underlying disease. Increased attention must also be paid to biological therapy in pregnancy and planned (predictable) vaccinations as well as existing infections, such as SARS-CoV-2 infection. Before starting a biological therapy, the immune status should be checked with regard to chronic viral and bacterial infections and, if necessary, the vaccination status should be refreshed or missing vaccinations should be made up for before starting therapy. Currently, reliable data on the effect of biologicals on the immunological situation of SARS-CoV-2 infection and COVID-19 are not available. Therefore, research and development of suitable diagnostic methods for detection of immunologically caused side effects as well as detection of potential therapy responders and non-responders is of great importance.

Therapeutic targeting of the IL-13 pathway in skin inflammation

Introduction: Atopic dermatitis (AD) is a heterogeneous, chronic, inflammatory skin disease with a non-negligible prevalence at present. Its pathogenesis is complex, but mainly characterized by constitutive T helper type 2 (Th2)-cell activation. Systemic therapies for moderate-to-severe AD can be associated with adverse events that encumber their satisfactory long-term use. Several drugs targeting relevant molecules in the immunopathogenesis of AD have been approved or are under clinical development for the treatment of moderate to severe AD. To elaborate this review, literature searches were performed in PubMed on 29 August 2020.Areas covered: This narrative literature review is focused on the pivotal role of IL-13 in the immunopathogenesis of AD and other skin diseases.Expert opinion: Dupilumab has demonstrated the central role of IL-13 and IL-4 in the pathogenesis of AD, asthma, and other diseases in the atopic spectrum. In addition, phase III randomized clinical trials (RCTs) evaluating specific blockade of IL-13 with tralokinumab for treatment of AD also demonstrated favorable results, and phase III RCT evaluating lebrikizumab are ongoing. The role of IL-13 in other skin diseases should be further investigated.

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

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

Itch: A Paradigm of Neuroimmune Crosstalk

Although the medical definition of itch has been in existence for 360 years, only in the last 20 years have we begun to understand the basic mechanisms that underlie this unique sensation. Therapeutics that specifically target chronic itch as a pathologic entity are currently still not available. Recent seminal advances in itch circuitry within the nervous system have intersected with discoveries in immunology in unexpected ways to rapidly inform emerging treatment strategies. The current review aims to introduce these basic concepts in itch biology and highlight how distinct immunologic pathways integrate with recently identified itch-sensory circuits in the nervous system to inform a major new paradigm of neuroimmunology and therapeutic development for chronic itch.

Emerging systemic therapies for atopic dermatitis: biologics

BACKGROUND

The mainstay of atopic dermatitis treatment has been largely unchanged over the last few decades. With improved understanding of the immunologic pathways underlying atopic dermatitis in recent years, targeted biologic therapies are being developed.

OBJECTIVE

Discuss efficacy and safety profiles of emerging biologics in phase 2 and 3 clinical trials.

METHODS

A systemic literature review was conducted to identify results of randomized, placebo-controlled trials of monoclonal antibodies up to March 1, 2020 for the treatment of atopic dermatitis.

RESULTS

Targeted biologics appear to have acceptable safety profiles. Dupilumab, lebrikizumab, and nemolizumab demonstrate efficacy as agents producing improvement in clinical severity and pruritus.

CONCLUSIONS

The growing class of biologics shows promise in meeting the needs of treatment-resistant atopic dermatitis. The use of validated core measurements is necessary for future trials in order to adequately compare agents and progress evidence-based medicine.

Emerging Therapeutic Options for Chronic Pruritus

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

Systemic treatments for eczema: a network meta-analysis

BACKGROUND

Eczema is a common and chronic, relapsing, inflammatory skin disorder. It seriously impacts quality of life and economic outcomes, especially for those with moderate to severe eczema. Various treatments allow sustained control of the disease; however, their relative benefit remains unclear due to the limited number of trials directly comparing treatments.

OBJECTIVES

To assess the comparative efficacy and safety of different types of systemic immunosuppressive treatments for moderate to severe eczema using NMA and to generate rankings of available systemic immunosuppressive treatments for eczema according to their efficacy and safety.

SEARCH METHODS

We searched the following databases up to August 2019: the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, and Embase.

SELECTION CRITERIA

All randomised controlled trials (RCTs) of systemic immunosuppressive agents for moderate to severe atopic eczema when compared against placebo or any other eligible eczema treatment.

DATA COLLECTION AND ANALYSIS

We synthesised data using pair-wise analysis and NMA to compare treatments and rank them according to their effectiveness. Effectiveness was assessed primarily by determining the proportion of participants who achieved at least 75% improvement in the Eczema Area and Severity Index (EASI75) and improvement in the Patient-Oriented Eczema Measure (POEM). Safety was evaluated primarily by considering the proportion of participants with serious adverse events (SAEs) and infection. We deemed short-term follow-up as ≤ 16 weeks and long-term follow-up as > 16 weeks. We assessed the certainty of the body of evidence from the NMA for these primary outcomes using six domains of CiNEMA grading.

MAIN RESULTS

We included a total of 74 studies, with 8177 randomised participants. Approximately 55% of participants were male, with average age of 32 years (range 2 to 84 years), although age and gender were unreported for 419 and 902 participants, respectively. Most of the included trials were placebo controlled (65%), 34% were head-to-head studies (15% assessed the effects of different doses of the same drug), and 1% were multi-armed studies with both an active comparator and a placebo. All trials included participants with moderate to severe eczema, but 62% of studies did not separate data by severity; 38% of studies assessed only severe eczema. The total duration of included trials ranged from 2 weeks to 60 months, whereas treatment duration varied from a single dose (CIM331, KPL-716) to 60 months (methotrexate (MTX)). Seventy studies were available for quantitative synthesis; this review assessed 29 immunosuppressive agents from three classes of interventions. These included (1) conventional treatments, with ciclosporin assessed most commonly; (2) small molecule treatments, including phosphodiesterase (PDE)-4 inhibitors, tyrosine kinase inhibitors, and Janus kinase (JAK) inhibitors; and (3) biological treatments, including anti-CD31 receptors, anti-interleukin (IL)-22, anti-IL-31, anti-IL-13, anti-IL-12/23p40, anti-OX40, anti-TSLP, anti-CRTH2, and anti-immunoglobulin E (IgE) monoclonal antibodies, but most commonly dupilumab. Most trials (73) assessed outcomes at a short-term duration ranging from 2 to 16 weeks, whereas 33 trials assessed long-term outcomes, with duration ranging from 5 to 60 months. All participants were from a hospital setting. Fifty-two studies declared a source of funding, and of these, pharmaceutical companies funded 88%. We rated 37 studies as high risk; 21, unclear risk, and 16, low risk of bias, with studies most commonly at high risk of attrition bias. Network meta-analysis suggests that dupilumab ranks first for effectiveness when compared with other biological treatments. Dupilumab is more effective than placebo in achieving EASI75 (risk ratio (RR) 3.04, 95% confidence interval (CI) 2.51 to 3.69) and improvement in POEM score (mean difference 7.30, 95% CI 6.61 to 8.00) at short-term follow-up (high-certainty evidence). Very low-certainty evidence means we are uncertain of the effects of dupilumab when compared with placebo, in terms of the proportion of participants who achieve EASI75 (RR 2.59, 95% CI 1.87 to 3.60) at longer-term follow-up. Low-certainty evidence indicates that tralokinumab may be more effective than placebo in achieving short-term EASI75 (RR 2.54, 95% CI 1.21 to 5.34), but there was no evidence for tralokinumab to allow us to assess short-term follow-up of POEM or long-term follow-up of EASI75. We are uncertain of the effect of ustekinumab compared with placebo in achieving EASI75 (long-term follow-up: RR 1.17, 95% CI 0.40 to 3.45; short-term follow-up: RR 0.91, 95% CI 0.28 to 2.97; both very low certainty). We found no evidence on ustekinumab for the POEM outcome. We are uncertain whether other immunosuppressive agents that targeted our key outcomes influence the achievement of short-term EASI75 compared with placebo due to low- or very low-certainty evidence. Dupilumab and ustekinumab were the only immunosuppressive agents evaluated for longer-term EASI75. Dupilumab was the only agent evaluated for improvement in POEM during short-term follow-up. Low- to moderate-certainty evidence indicates a lower proportion of participants with SAEs after treatment with QAW039 and dupilumab compared to placebo during short-term follow-up, but low- to very low-certainty evidence suggests no difference in SAEs during short-term follow-up of other immunosuppressive agents compared to placebo. Evidence for effects of immunosuppressive agents on risk of any infection during short-term follow-up and SAEs during long-term follow-up compared with placebo was of low or very low certainty but did not indicate a difference. We did not identify differences in other adverse events (AEs), but dupilumab is associated with specific AEs, including eye inflammation and eosinophilia.

AUTHORS' CONCLUSIONS

Our findings indicate that dupilumab is the most effective biological treatment for eczema. Compared to placebo, dupilumab reduces eczema signs and symptoms in the short term for people with moderate to severe atopic eczema. Short-term safety outcomes from clinical trials did not reveal new safety concerns with dupilumab. Overall, evidence for the efficacy of most other immunosuppressive treatments for moderate to severe atopic eczema is of low or very low certainty. Given the lack of data comparing conventional with newer biological treatments for the primary outcomes, there remains high uncertainty for ranking the efficacy and safety of conventional treatments such as ciclosporin and biological treatments such as dupilumab. Most studies were placebo-controlled and assessed only short-term efficacy of immunosuppressive agents. Further adequately powered head-to-head RCTs should evaluate comparative long-term efficacy and safety of available treatments for moderate to severe eczema.

Fractional Carbon Dioxide Laser is Effective in Amelioration of Pruritus in Primary Cutaneous Amyloidosis: A Clinical and Biochemical Study

BACKGROUND AND OBJECTIVES

Primary cutaneous amyloidosis (PCA) is a pruritic disease characterized by amyloid deposition in the skin. Interleukin-31 (IL-31) is a pruritus-mediating cytokine. Fractional carbon dioxide (CO₂ ) laser has shown efficacy in the treatment of PCA regarding the clinical appearance, histological pattern, and pruritus. The aim of this study is to assess the effect of fractional CO₂ laser on pruritus associated with PCA, and analyze whether this effect is related to IL-31 and IL-31 receptor (R) expression.

STUDY DESIGN/MATERIALS AND METHODS

The study included 24 patients with PCA and 24 healthy controls. Each patient received four fractional CO₂ laser sessions, 4 weeks apart, using the superficial ablative mode. Skin biopsies were taken from patients before and after treatment, as well as controls, for assessment of IL-31 and IL-31R by real-time polymerase chain reaction.

RESULTS

Treatment resulted in significant improvement of all clinical parameters, including pruritus (P < 0.001). Patients before treatment had significantly higher IL-31 and IL-31R than controls (P = 0.000 for both). In addition, there was a statistically significant decrease in IL-31 and IL-31R after treatment than their values before treatment (P = 0.000 for both).

CONCLUSION

This study confirms the therapeutic efficacy of fractional CO₂ laser in treatment of PCA. Reduction of IL-31 and its receptor seems to be one of the involved mechanisms; however, its relation to improvement of pruritus is still not clear. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Simple Approach to Accurately Predict Pharmacokinetics of Therapeutic Monoclonal Antibodies after Subcutaneous Injection in Humans

BACKGROUND AND OBJECTIVE

The subcutaneous injection of therapeutic monoclonal antibodies is increasingly used in the treatment of several diseases because of its convenience. Thus, a simple and accurate method of predicting the pharmacokinetics of monoclonal antibodies after a subcutaneous injection in humans would be a valuable tool for preclinical/clinical development. In this study, we investigated whether the pharmacokinetics of monoclonal antibodies after a subcutaneous injection in humans can be predicted using only pharmacokinetic data after a subcutaneous injection in cynomolgus monkeys.

METHODS

First, we compared the accuracy of three approaches to predict the apparent clearance (CL/F) and apparent volume of distribution (V_d/F) for 15 monoclonal antibodies in humans (1) allometric scaling from cynomolgus monkeys; (2) geometric mean of reported values in humans; (3) estimation from a regression line based on CL/F in humans [only V_d/F]). Then, using the predicted CL/F and V_d/F, and the geometric mean of reported absorption rate constant of mAbs the plasma concentration-time profiles of 13 monoclonal antibodies after subcutaneous injections in humans were simulated.

RESULTS

In a comparison of approaches, the first approach showed the best prediction accuracy for CL/F with an exponent of 0.9 (100% and 73% prediction accuracy within 2- and 1.5-fold of the observed value),and the third approach was the best for V_d/F (100% prediction accuracy within 1.5-fold of the observed value). Next, using the first approach for CL/F and the third approach for V_d/F, we accurately predicted the plasma concentration-time profiles of 13 monoclonal antibodies after subcutaneous injections in humans.

CONCLUSION

This simple approach can be applied in preclinical and clinical settings to predict the pharmacokinetics of monoclonal antibodies after subcutaneous injections in humans. Further, this approach requires only CL/F after a subcutaneous injection in cynomolgus monkeys, contributing to animal welfare and reducing costs.