Prevalence of prurigo nodularis in the United States of America: A retrospective database analysis

A critical evaluation of nemolizumab for prurigo nodularis

INTRODUCTION

Prurigo nodularis (PN) is a chronic inflammatory skin condition that presents with intensely pruritic, hyperkeratotic nodules. The pathophysiology underlying PN is not entirely clear, making treatment challenging. Patients often require a multimodal approach, although many of the available therapies have low efficacy or adverse effects.

AREAS COVERED

In this review, we discuss the use of nemolizumab for the treatment of PN in adults. Nemolizumab is a biological therapy that reduces type 2 cytokines and the neuroimmune response implicated in the pathophysiology of PN. It also helps maintain skin barrier integrity, which may be damaged during the vicious itch-scratch cycle. Nemolizumab has demonstrated great efficacy in improving itch and clearing lesions in recent clinical trials with respectable tolerance.

EXPERT OPINION

Nemolizumab is a promising drug for PN that seems comparable to the recently approved dupilumab in terms of its therapeutic effect and excellent safety profile, although nemolizumab may work more rapidly on itch. JAK inhibitors are also emerging as competitors of biologics for PN, however, their safety profile in this population may differ. Trials evaluating these drugs are needed to assess which is preferable. Additional data on the durability and longevity of nemolizumab for PN treatment is highly anticipated.

Clinical aspects and management of chronic itch

Chronic pruritus (CP) (ie, itch that persists for more than 6 weeks) poses significant challenges to patients' health and quality of life. It is a common reason for visits to dermatologists and general practitioners and can be caused by a range of conditions, including systemic diseases such as chronic kidney disease or liver diseases, malignancies, neuropathic conditions, and dermatoses such as atopic dermatitis. CP often does not develop in parallel with the course of the disease and can become an entity of its own, which must be treated with antipruritic drugs, even if the underlying cause is already under therapy. Depending on the etiology of CP, different pathways in the pathogenesis have been analyzed recently, following which new treatments have been developed and tested in randomized controlled trials. This article discusses the recent results of these studies and highlights how best to manage health care for patients with CP.

Efficacy and safety of vixarelimab, a human monoclonal oncostatin M receptor β antibody, in moderate-to-severe prurigo nodularis: a randomised, double-blind, placebo-controlled, phase 2a study

BACKGROUND

Prurigo nodularis is a chronic skin disease characterised by intensely pruritic, hyperkeratotic nodules. Vixarelimab, a human monoclonal antibody, binds to the beta subunit of the oncostatin M receptor, inhibiting signalling of both interleukin 31 and oncostatin M, two cytokine pathways that contribute to pruritus and nodule formation in prurigo nodularis.

METHODS

This double-blind, placebo-controlled, phase 2a trial was done at both private and academic dermatology outpatient research clinics across the United States and Canada (n = 40). Patient eligibility criteria included age 18-75 years, physician-documented diagnosis of prurigo nodularis minimum 6 months duration of prurigo nodularis, presence of at least 10 pruritic nodules approximately 0.5-2 cm in size on at least two different anatomical locations (excluding face and scalp) and involving the extremities, and presence of normal-appearing skin between nodules; atopic dermatitis as a comorbidity was exclusionary. Patients were required to have moderate-to-severe pruritus, defined as Worst Itch-Numeric Rating Scale (WI-NRS) score ≥7 at screening and LS-mean weekly WI-NRS score ≥5 for each of the 2 consecutive weeks immediately before randomisation. Participants were randomly assigned (1:1) to receive weekly subcutaneous vixarelimab 360 mg (720 mg loading dose) or placebo using stratification factors (sex and presence of atopy) and block size 4 through the IWRS system. Stratification by atopy status was based on the reported high prevalence of atopy in this population and the potential impact of atopy in the immunopathologic process in prurigo nodularis. Patients, investigators, study sponsor, and site staff were masked to study treatment. The primary efficacy endpoint was least squares (LS)-mean percent change from baseline (PCFB) at Week 8 in weekly average Worst Itch-Numeric Rating Scale (WI-NRS) score. The primary efficacy endpoint was analysed with ANCOVA including treatment as fixed effect, with baseline WI-NRS, and randomisation stratification factor as covariates. All randomised patients who had at least 1 dose of study drug or placebo were included in the Safety Analysis Set. This trial is registered at ClinicalTrials.gov, NCT03816891.

FINDINGS

Of 50 patients randomised between March 11, 2019 and January 31, 2020, 23 vixarelimab recipients and 26 placebo recipients comprised the modified intent-to-treat analysis population (baseline LS-mean [SD] WI-NRS score, 8.3 [1.05]). Outcomes at Week 8 for vixarelimab versus placebo included LS-mean PCFB in WI-NRS score, -50.6% versus -29.4% (LS-mean difference [95% CI], -21.2% [-40.82, -1.60]; p = 0.03); ≥4-point reduction in WI-NRS score, 52.2% (12/23) versus 30.8% (8/26) (p = 0.11); PN-IGA score of 0 or 1, 30.4% (7/23) versus 7.7% (2/26) (p = 0.03); LS-mean PCFB in pruritus VAS score, -54.4% versus -32.6% (p = 0.03); and LS-mean PCFB sleep loss reduction (improvement), -56.3% versus -30.0% (p = 0.02). No deaths, serious TEAEs, or TEAEs leading to dose interruption were reported. The percentage of vixarelimab recipients reporting any TEAE was 91.3% (21/23) versus 76.9% (20/26) of placebo recipients; drug-related TEAEs generally were similar between the two groups (vixarelimab, 43.5% [10/23]; placebo, 38.5% [10/26]).

INTERPRETATION

Vixarelimab demonstrated rapid reduction of pruritus and achievement of clear/almost clear skin in one-third of the patients by Week 8. Relief of itch and clearing of skin nodules represent two important potential therapeutic advances in the management of patients suffering from the debilitating disease Prurigo Nodularis.

FUNDING

Kiniksa Pharmaceuticals, Ltd.

[Update on the treatment of chronic prurigo]

Chronic prurigo is an inflammatory dermatosis defined by the presence of chronic pruritus and single to multiple symmetrically distributed pruriginous lesions such as nodules, papules, and plaques. Various dermatological, systemic, neurological, and/or psychiatric diseases are associated with chronic prurigo. The care of these patients is very complex due to the multifactorial character and also because of the sometimes very pronounced consequences such as an impairment of quality of life with sleep disorders. Furthermore, there are no approved therapies. The current guideline-based treatment recommendations include topical application of steroids, capsaicin, calcineurin inhibitors, phototherapy, and systemic use of gabapentinoids, μ‑opioid receptor antagonists, immunosuppressants, or dupilumab. Results from randomized controlled trials and case series on new therapies including biologics (e.g., nemolizumab) and Janus kinase inhibitors are promising. This article provides an overview of currently available treatment options and discusses the latest data on the efficacy of future therapies.

Unmet Medical Needs in Chronic, Non-communicable Inflammatory Skin Diseases

An estimated 20-25% of the population is affected by chronic, non-communicable inflammatory skin diseases. Chronic skin inflammation has many causes. Among the most frequent chronic inflammatory skin diseases are atopic dermatitis, psoriasis, urticaria, lichen planus, and hidradenitis suppurativa, driven by a complex interplay of genetics and environmental factors. Autoimmunity is another important cause of chronic skin inflammation. The autoimmune response may be mainly T cell driven, such as in alopecia areata or vitiligo, or B cell driven in chronic spontaneous urticaria, pemphigus and pemphigoid diseases. Rare causes of chronic skin inflammation are autoinflammatory diseases, or rheumatic diseases, such as cutaneous lupus erythematosus or dermatomyositis. Whilst we have seen a significant improvement in diagnosis and treatment, several challenges remain. Especially for rarer causes of chronic skin inflammation, early diagnosis is often missed because of low awareness and lack of diagnostics. Systemic immunosuppression is the treatment of choice for almost all of these diseases. Adverse events due to immunosuppression, insufficient therapeutic responses and relapses remain a challenge. For atopic dermatitis and psoriasis, a broad spectrum of innovative treatments has been developed. However, treatment responses cannot be predicted so far. Hence, development of (bio)markers allowing selection of specific medications for individual patients is needed. Given the encouraging developments during the past years, we envision that many of these challenges in the diagnosis and treatment of chronic inflammatory skin diseases will be thoroughly addressed in the future.

Immunotargets and Therapy for Prurigo Nodularis

Prurigo nodularis is a chronic inflammatory skin disease consisting of severely pruritic nodules that can be very debilitating for patients. The basis of this skin condition is immunological dysregulation and neural amplification, driven by T-lymphocytes, mast cells, eosinophilic granulocytes, macrophages, and cytokines mediating itchy processes. Further complicating this already taxing diagnosis is the lack of approved treatment and consensus on management; although there are off-label treatments utilized as therapy. Immunomodulators are the cornerstone of treatment for PN, and additional novel therapies targeting key players in the immunological cascade are currently undergoing investigation. In this review, we will highlight targets of the immune cascade and explore current immunomodulating treatments as well as immunotherapies on the horizon for the management of prurigo nodularis.

Epidemiology of prurigo nodularis in England: a retrospective database analysis

OBJECTIVES

Prurigo nodularis is a debilitating skin condition that is classified as rare by the Genetic and Rare Diseases Information Center (GARD) and National Organization for Rare Diseases (NORD). There are no estimates of the prevalence of prurigo nodularis in England. We aimed to address this data gap by describing the epidemiology of prurigo nodularis in a representative dataset derived from the English National Health Service.

METHODS

The study utilised data from the Clinical Practice Research Datalink linked to Hospital Episode Statistics inpatient data. Patients with a diagnosis of prurigo nodularis were selected by clinical code in the primary care or inpatient datasets. Case definition was based on a minimum of two distinct diagnoses to maximize specificity. Point prevalence was calculated for the midpoint of 2018 and incidence rates from 2008-2018 presented. For those classified as incident cases, demographic and clinical characteristics were reported. In sensitivity analyses the case definition was modified to relax the multiple diagnosis criteria and to restrict cases to those diagnosed within a maximum of four or ten years of the midpoint prevalence date.

RESULTS

11,656 patients within the dataset had at least one prurigo nodularis diagnosis. Following application of the relevant inclusion criteria 2,743 patients formed the point prevalent cohort; an estimated prevalence of 3.27 patients per 10,000 (95% CI 3.15-3.40). In sensitivity analyses the estimated prevalence ranged from 2.24 (2.14-2.34) to 6.98 (6.8-7.16). Incidence over the study period was 2.88 per 100,000 patient years. Comorbidity was relatively high in this population notably for atopic dermatitis (52.2%), depression (41.1%) and anxiety (35.4%).

CONCLUSION

This study supports the NORD/GARD classification of prurigo nodularis as a rare disease with a prevalence of 3.27 patients per 10,000 equating to 18,471 patients living with the disease in England in 2018. The relatively high prevalence of comorbidity observed for these patients may increase the complexity of management.

Epidemiology, Comorbidities, and Prescription Patterns of Korean Prurigo Nodularis Patients: A Multi-Institution Study

Prurigo nodularis (PN) is a chronic dermatosis typified by extraordinarily itchy nodules. However, little is known of the nature and extent of PN in Asian people. This study aimed to describe the epidemiology, comorbidities, and prescription pattern of PN in Koreans based on a large dermatology outpatient cohort. Patients with PN were identified from the Catholic Medical Center (CMC) clinical data warehouse. Anonymized data on age, sex, diagnostic codes, prescriptions, visitation dates, and other relevant parameters were collected. Pearson correlation analysis was used to calculate the correlation between PN prevalence and patient age. Conditional logistic regression modeling was adopted to measure the comorbidity risk of PN. A total of 3591 patients with PN were identified at the Catholic Medical Center Health System dermatology outpatient clinic in the period 2007–2020. A comparison of the study patients with age- and sex-matched controls (dermatology outpatients without PN) indicated that PN was associated with various comorbidities including chronic kidney disease (adjusted odds ratio (aOR), 1.48; 95% confidence interval (CI), 1.29–1.70), dyslipidemia (aOR, 1.88; 95% CI, 1.56–2.27), type 2 diabetes mellitus (aOR, 1.37; 95% CI, 1.22–1.54), arterial hypertension (aOR, 1.50; 95% CI, 1.30–1.73), autoimmune thyroiditis (aOR, 2.43; 95% CI, 1.42–4.16), non-Hodgkin’s lymphoma (aOR, 1.95; 95% CI, 1.23–3.07), and atopic dermatitis (aOR, 2.16, 95% CI, 1.91–2.45). Regarding prescription patterns, topical steroids were most favored, followed by topical calcineurin inhibitors; oral antihistamines were the most preferred systemic agent for PN. PN is a relatively rare but significant disease among Korean dermatology outpatients with a high comorbidity burden compared to dermatology outpatients without PN. There is great need for breakthroughs in PN treatment.

Prevalence, incidence and presence of comorbidities in patients with prurigo and pruritus in Germany: A population-based claims data analysis

BACKGROUND

There are currently no published population-based data on prurigo and pruritus epidemiology in Germany.

OBJECTIVES

We present the prevalence, incidence and comorbidity frequency of prurigo and pruritus in Germany.

METHODS

This was a retrospective healthcare research study based on anonymized routine data from the German health insurance company DAK-Gesundheit. Evaluations were carried out for 2 006 003 adults who were insured as of 31 December 2010. Prurigo and pruritus diagnoses were based on International Classification of Diseases, Tenth Revision, German Modification (ICD-10-GM) codes.

RESULTS

Prevalence was determined to be 0.21% (adjusted for sex and age 0.19%) for prurigo and 2.21% (adjusted 2.14%) for pruritus in 2010. The adjusted rates extrapolated to the total German population in 2010 show that 130 685 adults would have received a prurigo diagnosis and 1 461 024 a diagnosis of pruritus. In 2011, incidence of new prurigo and pruritus cases was 0.13% (adjusted 0.12%, extrapolated 77 263 cases) and 1.51% (adjusted 1.46%, extrapolated 978 885), respectively. Adults with prurigo suffered most frequently from hypertension (35.16%), hyperlipidaemia (24.95%) and depression (21.97%); all were reported more frequently in patients with prurigo compared with the general population (P < 0.001). Similarly, adults with pruritus suffered most frequently from hypertension (31.28%), hyperlipidaemia (23.52%) and depression (18.91%) compared with patients without pruritus (P < 0.001).

CONCLUSIONS

Our data show that prurigo is a relatively rare but significant disease and that pruritus is frequent and very variable in appearance, and both have a high comorbidity burden.

Health-related quality of life and economic burden of prurigo nodularis

BACKGROUND

Prurigo nodularis (PN) is an understudied, pruritic inflammatory skin disease. Little is known about the effect of PN on quality of life and its associated economic burden.

OBJECTIVE

To quantify the impact of PN on quality of life and its economic implications.

METHODS

A cohort study of PN patients (n = 36) was conducted using the Health Utilities Index Mark 3 questionnaire. Control data from US adults (n = 4187) were obtained from the 2002-2003 Joint Canada/United States Survey of Health. Quality-adjusted life year loss and economic costs were estimated by comparing the Health Utilities Index Mark 3 scores of the PN patients with those of the controls.

RESULTS

The PN patients had lower overall health performance compared to the controls, (mean ± SE, 0.52 ± 0.06 vs 0.86 ± 0.003, respectively, P < .001). In multivariable regression, PN was found to be associated with worse health performance (coefficient -0.34, 95% CI [-0.46 to -0.23]), most prominent in the pain subdomain (coefficient -0.24, 95% CI [-0.35 to -0.13]). This correlated to an average of 6.5 lifetime quality-adjusted life years lost per patient, translating to an individual lifetime economic burden of $323,292 and a societal burden of $38.8 billion.

CONCLUSION

These results demonstrate that PN is associated with significant quality-of-life impairment, similar to the level of other chronic systemic conditions. PN is also associated with a substantial individual economic burden, emphasizing the necessity of research on effective treatment options.