Pre- and Postnatal Development Study of Nemolizumab, a Humanized Anti-Interleukin-31 Receptor A Monoclonal Antibody, in Cynomolgus Monkey

BACKGROUND

Nemolizumab, a humanized monoclonal antibody against interleukin-31 receptor A (IL-31RA), is used to treat atopic dermatitis and prurigo nodularis. These inflammatory skin diseases affect a wide range of age groups, including pregnant women and children; however, little is known about their biological effects on pre- and postnatal development. Therefore, we report and discuss the results of an enhanced pre- and postnatal development study in cynomolgus monkeys treated with nemolizumab, which also incorporates an assessment of juvenile toxicities.

METHODS

Nemolizumab was subcutaneously administered at doses of 1 or 25 mg/kg to pregnant cynomolgus monkeys once every 2 weeks (biweekly) from Gestation Day 20 until delivery, to investigate the potential toxicities on pre- and postnatal development. Additionally, their offspring were subcutaneously dosed biweekly with 1 or 25 mg/kg from approximately 1 to 7 months after birth to investigate the potential toxicities on juveniles, considering the age of the target patient population. The examination included tests for immune function and nervous system involvement by IL-31, as well as the standard assessments outlined in the ICH S5 guideline to comprehensively assess the safety profile.

RESULTS

No nemolizumab-related toxicities were observed in both dams and offspring up to 25 mg/kg. Maternal plasma nemolizumab concentrations were well maintained during the gestation period, gradually decreasing after delivery. Plasma concentrations in the offspring, higher than in dams, was maintained until scheduled necropsy.

CONCLUSION

Blocking IL-31 signaling with repeated dosing of nemolizumab did not adversely affect pregnancy, parturition, nursing, or postnatal physical and functional development in cynomolgus monkeys.

The role of nemolizumab in the treatment of atopic dermatitis for the adult population

Atopic dermatitis (AD) often requires long-term treatment that may be associated with adverse effects. This review aims to characterize nemolizumab as a treatment for AD in adults. A literature search was performed to assess nemolizumab's role in moderate-to-severe AD in adults. Currently, clinical trials are being conducted to evaluate the clinical efficacy, safety profile and optimal dosing of nemolizumab for adults with moderate-to-severe AD. The most common adverse effects include nasopharyngitis, AD exacerbation and increased blood creatinine phosphokinase. Recent data from clinical trials suggest nemolizumab may be an acceptable treatment in adults with moderate-to-severe AD.

Interleukin antagonists for atopic dermatitis: a new era of therapy

INTRODUCTION

Over the last decade, increasing understanding of the immunopathogenesis of atopic dermatitis (AD) enabled the recognition of multiple therapeutic targets and subsequently the development of novel, highly effective systemic treatments, including interleukin (IL)-antagonists. To date, the IL-4Ra-inhibitor dupilumab and the IL-13 inhibitor tralokinumab have gained regulatory approval in Europe for the treatment of moderate-to-severe AD, while more than 70 new therapeutics are currently in development.

AREAS COVERED

In this review, we address the role of ILs in the pathogenesis of AD and provide an overview of the novel and investigational IL-antagonists, as regards their efficacy and safety on moderate-to-severe AD.

EXPERT OPINION

Current data have established IL-4 and IL-13 inhibitors as effective and safe for the treatment of moderate-to-severe AD, as regards the rapid control of flares as well as the long-term remission of the disease. Data regarding the efficacy and safety of other IL-inhibitors, including those targeting IL-31, IL-22, IL-33, IL-36 and IL-18, are accumulating. There is still an unmet need for real-world-evidence studies and head-to-head studies for both currently available and future agents in AD treatment. Establishing predictive biomarkers of treatment response in a disorder of such considerable heterogenicity might help physicians pursue a patient-tailored therapeutic response.

Update on the role of cytokines and chemokines in canine atopic dermatitis

BACKGROUND

Cytokines and chemokines play central roles in the pathogenesis of canine atopic dermatitis (cAD). Numerous studies have been published and provide new insights into their roles in cAD.

OBJECTIVES

To summarise the research updates on the role of cytokines and chemokines in the pathogenesis of cAD since the last review by the International Committee on Allergic Diseases of Animals in 2015.

MATERIAL AND METHODS

Online citation databases, abstracts and proceedings from international meetings on cytokines and chemokines relevant to cAD that had been published between 2015 and 2022 were reviewed.

RESULTS

Advances in technologies have allowed the simultaneous analysis of a broader range of cytokines and chemokines, which revealed an upregulation of a multipolar immunological axis (Th1, Th2, Th17 and Th22) in cAD. Most studies focused on specific cytokines, which were proposed as potential novel biomarkers and/or therapeutic targets for cAD, such as interleukin-31. Most other cytokines and chemokines had inconsistent results, perhaps as a consequence of their varied involvement in the pathogenesis of different endotypes of cAD.

CONCLUSIONS AND CLINICAL RELEVANCE

Inconsistent results for many cytokines and chemokines illustrate the difficulty of studying the complex cytokine and chemokine networks in cAD, and highlight the need for more comprehensive and structured studies in the future.

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.

IL-31-Pruritus Interleukin: Serum Values and Clinical Impact in Chronic Spontaneous Urticaria-A Romanian Retrospective Study

(1) Background: This study aimed to evaluate the implications of interleukin-31 (IL-31) in the pathogenesis of chronic spontaneous urticaria (CSU) and to assess the differences that occur between its serum values compared to controls. Additionally, the serum IL-31 levels were measured alongside other clinical and paraclinical parameters that were identified in the patients to understand its immunological importance in this skin disease and to determine if it could potentially serve as a therapeutic target in CSU in the future. (2) Methods: The serum levels of IL-31 were estimated in 50 patients diagnosed with CSU according to the accepted international guidelines. Additionally, 38 controls who had not experienced any episodes of urticaria during their lifetime were included. (3) Results: Significantly elevated serum IL-31 levels were observed in CSU patients compared to the controls (p < 0.0001). Although no direct correlations were found between IL-31 and inflammatory markers (erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)), eosinophils, or total immunoglobulins E (IgE), significant differences in IL-31 levels were identified based on CSU severity, quality of life impact, itch intensity, and response to histamine H1 receptor antagonists (H1 antihistamines) (p < 0.05 for all). (4) Conclusions: Our findings underscore that IL-31 is not directly associated with general inflammation, eosinophilic response, or atopy in CSU. Nevertheless, its expression is influenced by key disease characteristics: severity, pruritus, and H1 antihistamine response. This investigation provides essential insights into CSU pathogenesis, potentially leading to novel therapeutic interventions. An enhanced understanding of these mechanisms is crucial due to the limitations of current treatment modalities in terms of fully managing CSU symptoms.

Elevated Interleukin-31 Levels in Serum, but Not CSF of Dogs with Steroid-Responsive Meningitis-Arteritis Suggest an Involvement in Its Pathogenesis

Steroid-responsive meningitis-arteritis (SRMA) is a predominantly Th-2 immune-mediated disease, but the exact pathomechanism remains unclear. Interleukin-31 (IL-31) is predominantly produced by T cells with a Th-2 phenotype during proinflammatory conditions. We hypothesize that IL-31 might be involved in the pathogenesis of SRMA. IL-31 was measured in archived samples (49 serum and 52 CSF samples) of dogs with SRMA, meningoencephalitis of unknown origin (MUO), infectious meningoencephalitis, and atopic dermatitis, and of healthy control dogs using a competitive canine IL-31 ELISA. The mean serum IL-31 level in dogs with SRMA (n = 18) was mildly higher compared to dogs with atopic dermatitis (n = 3, p = 0.8135) and MUO (n = 15, p = 0.7618) and markedly higher than in healthy controls (n = 10, p = 0.1327) and dogs with infectious meningoencephalitis (n = 3, no statistics). Dogs with SRMA in the acute stage of the disease and without any pre-treatment had the highest IL-31 levels. The mean CSF IL-31 value for dogs with SRMA (n = 23) was quite similar to that for healthy controls (n = 8, p = 0.4454) and did not differ markedly from dogs with MUO (n = 19, p = 0.8724) and infectious meningoencephalitis. Based on this study, an involvement of IL-31 in the pathogenesis of the systemic Th-2 immune-mediated immune response in SRMA can be assumed as a further component leading to an aberrant immune reaction.

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.

Novel Therapeutic Targets for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease that significantly impacts quality of life. The pathogenesis of AD is a complex combination of skin barrier dysfunction, type II immune response, and pruritus. Progress in the understanding of the immunological mechanisms of AD has led to the recognition of multiple novel therapeutic targets. For systemic therapy, new biologic agents that target IL-13, IL-22, IL-33, the IL-23/IL-17 axis, and OX40-OX40L are being developed. Binding of type II cytokines to their receptors activates Janus kinase (JAK) and its downstream signal, namely signal transduction and activator of transcription (STAT). JAK inhibitors block the activation of the JAK-STAT pathway, thereby blocking the signaling pathways mediated by type II cytokines. In addition to oral JAK inhibitors, histamine H4 receptor antagonists are under investigation as small-molecule compounds. For topical therapy, JAK inhibitors, aryl hydrocarbon receptor modulators, and phosphodiesterase-4 inhibitors are being approved. Microbiome modulation is also being examined for the treatment of AD. This review outlines current and future directions for novel therapies of AD that are currently being investigated in clinical trials, focusing on their mechanisms of action and efficacy. This supports the accumulation of data on advanced treatments for AD in the new era of precision medicine.

Pathogenesis of allergic diseases and implications for therapeutic interventions

Allergic diseases such as allergic rhinitis (AR), allergic asthma (AAS), atopic dermatitis (AD), food allergy (FA), and eczema are systemic diseases caused by an impaired immune system. Accompanied by high recurrence rates, the steadily rising incidence rates of these diseases are attracting increasing attention. The pathogenesis of allergic diseases is complex and involves many factors, including maternal-fetal environment, living environment, genetics, epigenetics, and the body's immune status. The pathogenesis of allergic diseases exhibits a marked heterogeneity, with phenotype and endotype defining visible features and associated molecular mechanisms, respectively. With the rapid development of immunology, molecular biology, and biotechnology, many new biological drugs have been designed for the treatment of allergic diseases, including anti-immunoglobulin E (IgE), anti-interleukin (IL)-5, and anti-thymic stromal lymphopoietin (TSLP)/IL-4, to control symptoms. For doctors and scientists, it is becoming more and more important to understand the influencing factors, pathogenesis, and treatment progress of allergic diseases. This review aimed to assess the epidemiology, pathogenesis, and therapeutic interventions of allergic diseases, including AR, AAS, AD, and FA. We hope to help doctors and scientists understand allergic diseases systematically.

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.

IL-31 levels correlate with pruritus in patients with cholestatic and metabolic liver diseases and is farnesoid X receptor responsive in NASH

BACKGROUND AND AIMS

Pruritus is associated with multiple liver diseases, particularly those with cholestasis, but the mechanism remains incompletely understood. Our aim was to evaluate serum IL-31 as a putative biomarker of pruritus in clinical trials of an farnesoid X receptor (FXR) agonist, cilofexor, in patients with NASH, primary sclerosing cholangitis (PSC), and primary biliary cholangitis (PBC).

APPROACH AND RESULTS

Serum IL-31 was measured in clinical studies of cilofexor in NASH, PSC, and PBC. In patients with PSC or PBC, baseline IL-31 was elevated compared to patients with NASH and healthy volunteers (HVs). IL-31 correlated with serum bile acids among patients with NASH, PBC, and PSC. Baseline IL-31 levels in PSC and PBC were positively correlated with Visual Analog Scale for pruritus and 5-D itch scores. In patients with NASH, cilofexor dose-dependently increased IL-31 from Week (W)1 to W24. In patients with NASH receiving cilofexor 100 mg, IL-31 was higher in those with Grade 2-3 pruritus adverse events (AEs) than those with Grade 0-1 pruritus AEs. IL-31 weakly correlated with C4 at baseline in patients with NASH, and among those receiving cilofexor 100 mg, changes in IL-31 and C4 from baseline to W24 were negatively correlated. IL-31 messenger RNA (mRNA) was elevated in hepatocytes from patients with PSC and NASH compared to HVs. In a humanized liver murine model, obeticholic acid increased IL-31 mRNA expression in human hepatocytes and serum levels of human IL-31.

CONCLUSIONS

IL-31 levels correlate with pruritus in patients with cholestatic disease and NASH, with FXR agonist therapy resulting in higher serum levels in the latter group. IL-31 appears to derive in part from increased hepatocyte expression. These findings have therapeutic implications for patients with liver disease and pruritus.

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.

Nemolizumab: First Approval

Nemolizumab is a subcutaneously administered humanized anti-interleukin-31 (IL-31) receptor A (IL-31RA) monoclonal antibody that is being developed by Chugai Pharmaceutical Co. Ltd, Maruho Co. Ltd and Galderma Pharma S.A. for the treatment of skin diseases, including atopic dermatitis (AD), AD associated pruritus (ADaP), prurigo nodularis (PN), chronic kidney disease associated pruritus (CKDaP) and systemic sclerosis (SSc). IL-31 is a neuroimmune cytokine that induces itch, inflammation, keratinocyte differentiation and fibroblast activation in chronic pruritic skin diseases. Nemolizumab (Mitchga^® Syringes) was approved in Japan on 28 March 2022 for use in adults and children over the age of 13 years for the treatment of itch associated with AD (only when existing treatment is insufficiently effective). This article summarizes the milestones in the development of nemolizumab leading to this first approval.

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.

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.

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.

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.

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 .

The Protective Effects of IL-31RA Deficiency During Bleomycin-Induced Pulmonary Fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a severe fibrotic lung disease characterized by excessive collagen deposition and progressive decline in lung function. Th2 T cell-derived cytokines including IL-4 and IL-13 have been shown to contribute to inflammation and fibrotic remodeling in multiple tissues. Interleukin-31 (IL-31) is a newly identified cytokine that is predominantly produced by CD4 Th2 T cells, but its signaling receptor IL-31RA is primarily expressed by non-hematopoietic cells. However, the potential role of the IL-31-IL31RA axis in pulmonary inflammation and fibrosis has remained largely unknown. To determine the role of IL-31RA deficiency in pulmonary fibrosis, wildtype, and IL-31RA knockout mice were treated with bleomycin and measured changes in collagen deposition and lung function. Notably, the loss of IL-31 signaling attenuated collagen deposition and lung function decline during bleomycin-induced pulmonary fibrosis. The total lung transcriptome analysis showed a significant reduction in fibrosis-associated gene transcripts including extracellular matrix and epithelial cell-associated gene networks. Furthermore, the lungs of human IPF showed an elevated expression of IL-31 when compared to healthy subjects. In support, the percentage of IL-31 producing CD4⁺ T cells was greater in the lungs and PBMCs from IPF patients compared to healthy controls. Our findings suggest a pathogenic role for IL-31/IL-31RA signaling during bleomycin-induced pulmonary fibrosis. Thus, therapeutic targeting the IL-31-IL-31RA axis may prevent collagen deposition, improve lung function, and have therapeutic potential in pulmonary fibrosis.

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.

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.

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.

The ambiguous pruritogenic role of interleukin-31 in cutaneous T-cell lymphomas in comparison to atopic dermatitis: a review

Cutaneous T-cell lymphomas (CTCLs) comprise a group of chronic heterogeneous diseases of unknown pathogenesis, characterized by non-specific skin lesions such as patches, plaques and tumours. CTCL is accompanied by persistent pruritus poorly responding to antihistamines and therefore significantly reducing quality of life in patients with lymphomas. According to research data, interleukin-31 (IL-31) contributes to initiation and maintenance of the inflammatory process of the skin and pruritus in inflammatory dermatoses such as atopic dermatitis (AD), which is well established. The studies of a similar role of IL-31 in CTCLs are less homogenous. Due to contradictory reports concerning IL-31 and CTCL we have analysed available literature to summarize its role, focusing on CTCL and AD.

Trial of Nemolizumab and Topical Agents for Atopic Dermatitis with Pruritus

BACKGROUND

Nemolizumab is a subcutaneously administered humanized monoclonal antibody against interleukin-31 receptor A, which is involved in pruritus and inflammation in atopic dermatitis. In phase 2 studies, nemolizumab lessened the severity of atopic dermatitis.

METHODS

In a 16-week, double-blind, phase 3 trial, we randomly assigned Japanese patients with atopic dermatitis and moderate-to-severe pruritus and an inadequate response to topical agents in a 2:1 ratio to receive subcutaneous nemolizumab (60 mg) or placebo every 4 weeks until week 16, with concomitant topical agents. The primary end point was the mean percent change in the visual-analogue scale (VAS) score for pruritus (range, 0 to 100, with higher scores indicating worse pruritus) from baseline to week 16. Secondary end points included the time course of change in the VAS score for pruritus up to week 4, the change in the Eczema Area and Severity Index (EASI) score (range, 0 to 72, with higher scores indicating greater severity), a score of 4 or less on the Dermatology Life Quality Index (DLQI; range, 0 to 30, with higher scores indicating a greater effect on daily life), a score of 7 or less on the Insomnia Severity Index (ISI; range, 0 to 28, with higher scores indicating greater severity), and safety.

RESULTS

A total of 143 patients were randomly assigned to receive nemolizumab and 72 to receive placebo. The median VAS score for pruritus at baseline was 75. At week 16, the mean percent change in the VAS score was -42.8% in the nemolizumab group and -21.4% in the placebo group (difference, -21.5 percentage points; 95% confidence interval, -30.2 to -12.7; P<0.001). The mean percent change in the EASI score was -45.9% with nemolizumab and -33.2% with placebo. The percentage of patients with a DLQI score of 4 or less was 40% in the nemolizumab group and 22% in the placebo group; the percentage of patients with an ISI score of 7 or less was 55% and 21%, respectively. The incidence of injection-related reactions was 8% with nemolizumab and 3% with placebo.

CONCLUSIONS

In this 16-week trial, the use of subcutaneous nemolizumab in addition to topical agents for atopic dermatitis resulted in a greater reduction in pruritus than placebo plus topical agents. The incidence of injection-site reactions was greater with nemolizumab than with placebo. Longer and larger trials are necessary to determine whether nemolizumab has a durable effect and is safe for atopic dermatitis. (Funded by Maruho; JapicCTI number, 173740.).

Role of the Pruritic Cytokine IL-31 in Autoimmune Skin Diseases

Many autoimmune skin diseases, such as bullous pemphigoid (BP), psoriasis and certain types of chronic urticaria, are associated with intensive pruritus. While histamine and neuropeptides have previously been ascribed to play a role in itch that accompanies these diseases, recent evidence suggests that the pruritogenic cytokine interleukin (IL)-31 is a major driver of pruritic responses. IL-31 was originally shown to be produced by activated helper T cells, particularly Th2 cells, mast cells, macrophages and dendritic cells. However, more recent evidence demonstrated that eosinophils are a major source of this cytokine too, particularly in bullous pemphigoid. Basophils have also been shown to express the cytokine which, through autocrine action, strongly supports the production of other Th2-type cytokines from these cells. These investigations suggest that the dynamic recruitment of eosinophils and basophils in some autoimmune skin diseases could play an important role in the severity of IL-31-mediated itch. Furthermore, these studies suggest that IL-31, in addition to its pruritic actions, also has potential immunomodulatory roles in terms of supporting Th2-type immunity, which often underpins IgE-associated autoimmune diseases (such as bullous pemphigoid and urticaria) as well as allergies. While the role of IL-31 in psoriasis remains to be clarified, current evidence shows that this cytokine plays a major role in BP, chronic spontaneous urticaria and dermatomyositis. This suggests potential use of IL-31 receptor-blocking therapeutic approaches (e.g., Nemolizumab) for the treatment of IL-31-associated disorders.

Current pharmaceutical developments in atopic dermatitis

Atopic dermatitis (AD) is an inflammatory, pruritic, chronic or chronically relapsing skin disease that typically begins in early childhood and is occurring frequently in families with other atopic diseases (bronchial asthma and/or allergic rhino-conjunctivitis). Thanks to immunological and neurobiological research, the era of new treatments is coming as well as it occurred with psoriasis 15 years ago. Many treatments targeting cytokines (IL-4, IL-13, IL-31, TSLP) or neurotransmitters (substance P, opioids) or their respective receptors as well as phosphodiesterase-4 or the Jak/Stat pathways are under development. Antagonists of cytokines and anti-jak have promising effects on pruritus while it is more difficult to discriminate the effects of other drugs from the placebo effect on itch, which is known to be high.

Are Biologics Efficacious in Atopic Dermatitis? A Systematic Review and Meta-Analysis

BACKGROUND

Current systemic treatments for atopic dermatitis (AD) offer limited efficacy and are often restricted by safety concerns. Biologics may address the unmet need for improved AD therapeutics.

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of biologic agents in AD.

METHODS

A systematic review and meta-analysis of studies evaluating AD patients treated with biologics was performed. The primary outcome was the Eczema Area and Severity Index (EASI)-75 response, while secondary outcomes were SCOring Atopic Dermatitis (SCORAD)-75, EASI-50, SCORAD-50, Investigator Global Assessment 0/1 responses, change in responses from baseline, and adverse events.

RESULTS

We included 13 randomized controlled trials (RCTs) and 10 observational studies evaluating nine biologics. High-quality evidence was available for dupilumab, nemolizumab and ustekinumab. Pooling five studies, at weeks 12-16 dupilumab 300 mg every week to every 2 weeks achieved EASI-75 responses of 55%, superior to placebo [relative risk (RR) 3.3, 95% confidence interval (CI) 2.9-3.6]. Nemolizumab had similar EASI-75 responses as placebo, but significantly improved pruritus. In online reports, lebrikizumab demonstrated superior EASI-50 responses versus placebo (RR 1.3, 95% CI 1.04-1.7), while tralokinumab had superior SCORAD-50 responses versus placebo, with borderline significance (RR 1.7, 95% CI 0.97-3.1). In two RCTs each, omalizumab and ustekinumab were comparable with placebo, while antithymic stromal lymphopoietin receptor, infliximab, and rituximab lacked adequate evidence of efficacy. All medications had a comparable safety profile to placebo.

LIMITATIONS

Lack of RCTs and the use of variable outcome measures limited conclusions.

CONCLUSION

Dupilumab is currently the only biologic with robust evidence of efficacy in AD. Nemolizumab, lebrikizumab, and tralokinumab show promise but further data are needed. Longer follow-up and larger studies will establish their safety profile.