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

Dupilumab improves pruritus and skin lesions in patients with prurigo nodularis: Pooled results from 2 phase 3 trials (LIBERTY-PN PRIME and PRIME2)

Background

Phase 3 PRIME/PRIME2 trials independently demonstrated efficacy and an acceptable safety profile of dupilumab adults with moderate-to-severe prurigo nodularis.

Objective

To obtain a more precise estimate of onset and magnitude of treatment effect using PRIME/PRIME2 pooled data.

Methods

In PRIME/PRIME2, patients were randomized to dupilumab or placebo for 24 weeks. Pooled analysis assessed proportion of patients achieving clinically meaningful improvement in itch, clear/almost-clear skin, or both; at weeks 12 and 24; overall and by demographic subgroups and changes from baseline to week 24 in symptoms, signs, and quality of life.

Results

Patients receiving dupilumab (n = 153) vs placebo (n = 158) experienced significant improvements in all tested endpoints. At week 24, 90 (58.8%) dupilumab-treated vs 30 (19.0%) placebo-treated patients achieved clinically meaningful improvement in itch, 71 (46.4%) vs 27 (17.1%) clear/almost clear skin, and 54 (35.3%) vs 14 (8.9%) achieved both (P < .0001 for all). Treatment benefits were independent of baseline demographics. Safety to week 36 was generally consistent with the known dupilumab safety profile.

Limitations

On-treatment data limited to 24 weeks.

Conclusions

Pooled analysis confirmed improvements reported in individual trials and revealed earlier effect onset in itch and skin pain. Dupilumab treatment showed benefits across demographics.

Pathophysiology of Prurigo Nodularis: Neuroimmune Dysregulation and the Role of Type 2 Inflammation

Prurigo nodularis (PN) is a chronic, inflammatory skin condition characterized by multiple, intensely pruritic, distinctive nodular lesions. Subsequent scratching can further intensify the pruritus, culminating in a self-reinforcing itch-scratch cycle, which drives lesion development. The latest data indicate dysregulation of the neuroimmune axis in PN pathogenesis, including the involvement of sensory neurons, key effector immune cells, proinflammatory cytokines, dermal fibroblasts, and pruritogens. In this review, we highlight evidence supporting the role of type 2 immune axis dysregulation in driving the clinical presentation of PN and discuss how related signaling pathways may offer effective therapeutic targets to control PN signs and symptoms.

Worst Itch Numeric Rating Scale for Prurigo Nodularis: A Secondary Analysis of 2 Randomized Clinical Trials

Importance

Prurigo nodularis (PN) is a debilitating skin disease characterized by the hallmark symptom of chronic itch; the intensity of itch in PN was assessed using the Worst Itch Numeric Rating Scale (WI-NRS) to evaluate the primary efficacy end point of 2 recent phase 3 studies of dupilumab treatment for PN.

Objective

To validate the psychometric properties and to determine the clinically meaningful improvement threshold for WI-NRS in patients with moderate to severe PN.

Design, Setting, and Participants

In this secondary analysis of the PRIME and PRIME2 trials, content validity of WI-NRS was assessed through in-depth patient interviews. Psychometric assessments used pooled data from masked, intention-to-treat (ITT) patients with PN from randomized, double-masked, and placebo-controlled studies. Psychometric assessments included test-retest reliability, construct validity, known-groups validity, and sensitivity to change in adult patients with moderate-to-severe PN. Thresholds for meaningful within-patient improvement in the WI-NRS score were determined using anchor and distribution-based approaches. Data were analyzed after completion of each study, December 2019 to November 2021 for PRIME and January 2020 to August 2021 for PRIME2.

Exposures

Dupilumab (300 mg) or placebo subcutaneously every 2 weeks for 24 weeks.

Main outcomes and measures

WI-NRS score at specified time points up to 24 weeks after randomization.

Results

A total of 20 patients were included across the 2 studies (mean [SD] age, 49.3 [17.2] years; 11 female [55%]); 311 patients were included in the pooled intention-to-treat analysis (mean [SD] age, 49.5 [16.1] years; 203 female [65.3%]). The WI-NRS questions (20 of 20 patients), recall period (19 of 20 patients), and response scale (20 of 20 patients) were easy to understand and relevant for patients with PN. Adequate test-retest reliability was observed between screening and baseline (intraclass correlation coefficient = 0.72, using Patient Global Impression of Severity [PGIS] to define stable patients). Convergent and discriminant validity was supported by moderate to strong correlations (absolute r range = 0.34-0.73) with other conceptually related measures and weaker correlations (absolute r range = 0.06-0.32) with less-related measures, respectively. WI-NRS was sensitive to change, as demonstrated by differences in change from baseline among groups (per PGIS change and PGI of Change [PGIC]). Using anchor-based approach with PGIS and PGIC, the clinically meaningful improvement threshold was 4 points (range, 3.0-4.5), which was also supported by distribution-based methods.

Conclusion and Relevance

This study found that WI-NRS may be a fit-for-purpose instrument to support efficacy end points measuring the intensity of itching in adults with PN.

Trial Registration

NCT04183335 (PRIME) and NCT04202679 (PRIME2).

Dupilumab Therapy Modulates Circulating Inflammatory Mediators in Patients with Prurigo Nodularis

Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized by intense pruritus and skin nodules. Beyond the skin, PN involves circulating blood inflammation that may contribute to systemic disease comorbidities. Dupilumab was recently approved for treatment of PN, but its effects on systemic inflammation are unknown. Thus, we aimed to characterize changes in plasma concentrations of inflammatory proteins after dupilumab treatment. In this exploratory study, plasma samples were collected from 3 patients with moderate-to-severe PN before and after ≥6 months of dupilumab treatment. All patients exhibited clinically significant improvements after treatment. Of the 2569 proteins tested, 186 were differentially expressed after treatment (q < 0.1, fold change > 1.3). Downregulated proteins included cytokines associated with T helper (Th) 1 (IFN-γ, TNF-α), Th2 (IL-4, IL-13), and Th17/Th22 (IL-6, IL-22) signaling. Markers of innate immunity (IL-19, toll-like receptor 1, nitric oxide synthase 2), immune cell migration (CCL20, CD177), and fibrosis (IL-11, IL-22) were also decreased (q < 0.1). Gene set variation analysis of Th2, Th17, and epithelial-mesenchymal transition gene sets showed reduced pathway expression in the post-treatment cohort (P < .05). Plasma cytokine levels of IL-11, nitric oxide synthase 2, IL-13, IL-4, and IFNG (R2 > 0.75, q < 0.10) showed the strongest correlations with pruritus severity. Dupilumab may reduce systemic inflammatory proteins associated with multiple immune and fibrosis pathways in patients with PN, potentially modulating the development of systemic disease comorbidities.

Single-Cell RNA Sequencing Reveals Dysregulated POSTN+WNT5A+ Fibroblast Subclusters in Prurigo Nodularis

Prurigo nodularis (PN) is an intensely pruritic, inflammatory skin disease with a poorly understood pathogenesis. We performed single-cell transcriptomic profiling of 28,695 lesional and nonlesional PN cells. Lesional PN has increased dysregulated fibroblasts (FBs) and myofibroblasts. FBs in lesional PN were shifted toward a cancer-associated FB-like phenotype, with POSTN+WNT5A+ cancer-associated FBs increased in PN and similarly so in squamous cell carcinoma. A multicenter cohort study revealed an increased risk of squamous cell carcinoma and cancer-associated FB-associated malignancies (breast and colorectal) in patients with PN. Systemic fibroproliferative diseases (renal sclerosis and idiopathic pulmonary fibrosis) were upregulated in patients with PN. Ligand-receptor analyses demonstrated an FB neuronal axis with FB-derived WNT5A and periostin interactions with neuronal receptors melanoma cell adhesion molecule and ITGAV. These findings identify a pathogenic and targetable POSTN+WNT5A+ FB subpopulation that may predispose cancer-associated FB-associated malignancies in patients with PN.

Prevalence, Incidence and Treatment Patterns of Prurigo Nodularis in England: A Retrospective Database Analysis

BACKGROUND

Prurigo nodularis (PN) is a pruritic skin disease characterised by multiple, intensely itchy skin nodules in symmetrically distributed areas of the extremities. There are very limited studies on the epidemiology and treatment pathways for PN, especially moderate-to-severe PN, from England.

OBJECTIVES

To assess the epidemiology and treatment pathways of mild and moderate-to-severe PN in England.

METHODS

This retrospective cohort study used data from the Clinical Practice Research Datalink (CPRD) and Hospital Episode Statistics (HES) in England. Adult patients (≥18 years) with a PN specific diagnosis code any time between 1 April 2007 and 1 March 2019 (patient identification period) were selected. Patients were included if their first PN diagnostic code (index diagnosis date, IDD) was recorded during the identification period, with data available 6 months pre- and ≥12 months post-IDD. Patients were classified into moderate-to-severe PN (MSPN) or mild PN (MiPN) based on the presence or absence of a prescription record, post IDD, for either a systemic immunosuppressant or a gabapentinoid. Patients with MSPN and MiPN were matched 1:1 for age, gender and IDD. Prevalence and incidence were calculated for each year from 2007 to 2019. Drugs prescribed post IDD were analysed.

RESULTS

A total of 8,933 patients (MSPN: 2,498 patients; MiPN: 6,539 patients) were included for the study; 2,462 patients each with MiPN and MSPN were included for the comparative analysis. Atopic dermatitis, asthma and eosinophilic oesophagitis were significantly higher (all p<0.001) in patients with MSPN (vs MiPN). The prevalence of overall PN cases increased during the study period. The incidence rate also showed a similar trend. The rates of prescription of potent and super potent topical corticosteroids (TCS), topical calcineurin inhibitors, first- and second- generation antihistamines, oral and injectable systemic corticosteroid, methotrexate, antidepressants and tacrolimus were significantly higher (all p <0.001) in patients with MSPN (vs MiPN).

CONCLUSIONS

The epidemiology of PN was consistent with other European studies. Patients with MSPN received a significantly higher number of prescriptions for potent TCS and systemic drugs, as compared with milder patients.

Responder analysis using clinically meaningful thresholds: Post hoc analyses from randomized dupilumab clinical trials in patients with prurigo nodularis

BACKGROUND

Prurigo nodularis (PN) is an intensely pruritic disease characterized by itchy nodules on the trunk/extremities; it is often accompanied by skin pain and sleep disruption with negative impacts on the quality of life (QoL). The patient-reported outcome (PRO) instruments, Worst Itch-Numeric Rating Scale (WI-NRS), Skin Pain-NRS, Sleep-NRS and Dermatology Life Quality Index (DLQI) have been psychometrically validated and the clinically meaningful within-patient improvement thresholds (responder definition) have been established through data pooled from the two Phase-3 trials (PRIME, NCT04183335 and PRIME2, NCT04202679) of dupilumab in adults with PN uncontrolled on topical therapies.

OBJECTIVES

To estimate the proportion of dupilumab-treated patients (vs. placebo) achieving clinically meaningful improvement in itch, skin pain, sleep and QoL, either alone or in combination, from the data pooled from PRIME and PRIME2 trials.

METHODS

The patient-level data pooled from the two Phase-3 trials (N = 311) were used for this post hoc analysis. Thresholds of clinically meaningful within-patient improvement in PRO instrument scores from baseline at Week 24 used for defining responders were 4 (WI-NRS and Skin Pain-NRS), 2 (Sleep-NRS) and 9 points (DLQI). The proportion of dupilumab-treated patients, versus placebo, achieving the thresholds, and the time taken to achieve the thresholds were evaluated for the individual and combination of PROs.

RESULTS

Responder rates were significantly higher with dupilumab, versus placebo at Week 24 for WI-NRS (58.8% vs. 19.0%, p < 0.0001), Skin Pain-NRS (49.7% vs. 20.9%, p < 0.0001), Sleep-NRS (42.5% vs. 23.4%, p < 0.0001) and DLQI (64.7% vs. 22.8%, p < 0.0001). Proportion of patients achieving simultaneous improvement in symptoms and QoL (24.8% vs. 6.3%, p < 0.0001) were significantly higher in dupilumab-treated patients versus placebo. The time needed for achieving clinically meaningful improvement in symptoms were significantly lower in dupilumab-treated patients, versus placebo.

CONCLUSIONS

Significantly greater proportion of dupilumab-treated patients with PN, versus placebo, demonstrated clinically meaningful improvements in PRO measures of symptoms and QoL.

Prurigo nodularis: new insights into pathogenesis and novel therapeutics

Prurigo nodularis (PN) is an inflammatory skin condition characterized by intensely pruritic nodules on the skin. Patients with PN suffer from an intractable itch-scratch cycle leading to impaired sleep, psychosocial distress and a significant disruption in quality of life. The pathogenesis of PN is associated with immune and neural dysregulation, mediated by inflammatory cytokines [such as interleukin (IL)-4, -13, -17, -22 and -31] and neuropeptides (such as substance P and calcitonin gene-related peptide). There is a role for type 2 inflammation in PN in addition to T-helper (Th)17 and Th22-mediated inflammation. The neuroimmune feedback loop in PN involves neuropeptides released from nerve fibres that cause vasodilation and further recruitment of inflammatory cells. Inflammatory cells, particularly mast cells and eosinophils, degranulate and release neurotoxins, as well as nerve growth factor, which may contribute to the neuronal hyperplasia seen in the dermis of patients with PN and neural sensitization. Recent studies have also indicated underlying genetic susceptibility to PN in addition to environmental factors, the existence of various disease endotypes centred around degrees of type 2 inflammation or underlying myelopathy or spinal disc disease, and significant race and ethnicity-based differences, with African Americans having densely fibrotic skin lesions. Dupilumab became the first US Food and Drug Administration-approved therapeutic for PN, and there are several other agents currently in development. The anti-IL-31 receptor A inhibitor nemolizumab is in late-stage development with positive phase III data reported. In addition, the oral Janus kinase (JAK) 1 inhibitors, abrocitinib and povorcitinib, are in phase II trials while a topical JAK1/2 inhibitor, ruxolitinib, is in phase III studies.

Comorbidities, healthcare resource utilization & treatment pattern among patients with prurigo nodularis, compared to a benchmark in Germany: A real-world evidence claims data study

BACKGROUND

Prurigo nodularis (PN) is a rare chronic inflammatory skin disease with a high disease burden, but data on clinical and economic burden are still scarce.

OBJECTIVE

To describe the real-world epidemiologic, clinical and therapeutic characteristics and related economic burden of patients with PN compared to a benchmark population in Germany.

METHODS

This retrospective study was based on an excerpt of German Statutory Health Insurance data of patients with an initial PN diagnosis between 2012 and 2016. PN cohort contained no record of PN in eight quarters before the index quarter and was followed up for eight quarters (unless deceased). Benchmark cohort without PN was calculated using direct standardization and 1:1 matching to PN cohort.

RESULTS

Out of 4,536,002 insured patients, 2309 incident patients with PN were identified and matched to the benchmark cohort out of 3,018,382 patients without PN. Patients were mostly between 45 and 80 years when diagnosed with PN. Higher comorbidity rates were reported for PN than benchmark, with a rising disease burden at follow-up. Most patients with PN (91.3%) were diagnosed outpatient and had >50% more outpatient visits than the benchmark cohort. Hospitalization rates were higher in PN (53.9%) versus benchmark (35.1%), yielding twice longer mean hospital stays for PN (12 days) compared to benchmark (6 days) (p < 0.001). The most common initial therapy for patients with PN was topical corticosteroids (47.6%); ≥10% of patients were treated with antidepressants, antihistamines or systemic corticosteroids. Therapy rates were higher for PN compared to benchmark (p < 0.001). Mean initial costs were twofold higher in PN versus benchmark for outpatient, inpatient and drugs. During follow-up, an increase of >70% in mean PN costs compared to benchmark was identified for outpatient, inpatient and concomitant treatments (p < 0.001).

CONCLUSION

This study highlights the significantly higher clinical and economic burden incurred by PN compared to benchmark patients in Germany, reflecting the unmet medical need for PN.

Evaluating the Clinical Meaning of Dermatology Life Quality Index Scores Between Different Phenotypes of Atopic Dermatitis in Patients Before and After Biologic Therapy With Dupilumab

Background and Objective: Atopic Dermatitis (AD) is the most prevalent inflammatory skin disorder resulting in an intense impact on patients quality of life. The aim of this study is to evaluate the clinical meaning of the DLQI scores documented between different phenotypes of AD patients under biologic therapy with Dupilumab. Method: We conducted a retrospective analysis of 209 patients with AD treated with Dupilumab for 2 years. These patients were categorized into different clinical phenotypes. Severity of the disease was assessed by using the Eczema Area and Severity Index (EASI), Numerical Scale Rating (NRS) for sleep (NRS sleep), pruritus (NRS pruritus) and Dermatology Life Quality Index (DLQI) at baseline and subsequently at 4,12 and 24 months. Results: Our results show that the higher DLQI scores (mean: 18.6, range:9-30) achieved at T0 are associated with a prurigo nodularis AD pattern, while after 24 months (T3) of therapy with Dupilumab, the worst quality of life index results were reported in Flexural and Head-Neck combined clinical phenotypes. Conclusions: Quality of life is probably what matters most as an overall endpoint in AD. Assessing the clinical meaning of DLQI scores across different AD phenotypes could be a further aid when considering decision making factors in patient management.

Comprehensive plasma cytokine and chemokine profiling in prurigo nodularis reveals endotypes in Type 2 inflammation

Prurigo nodularis (PN) is a chronic inflammatory skin disease that is associated with variability in peripheral blood eosinophil levels and response to T-helper 2 targeted therapies (Th2). Our objective was to determine whether circulating immune profiles with respect to type 2 inflammation differ by race and peripheral blood eosinophil count. Plasma from 56 PN patients and 13 matched healthy controls was assayed for 54 inflammatory biomarkers. We compared biomarker levels between PN and HCs, among PN patients based on absolute eosinophil count, and across racial groups in PN. Eleven biomarkers were elevated in PN versus HCs including interleukin (IL)-12/IL-23p40, tumor necrosis factor-alpha (TNF-α), Thymic stromal lymphopoietin (TSLP), and macrophage-derived chemokine (MDC/CCL22). Additionally, PN patients with AEC > 0.3 K cells/μL had higher Th2 markers (eotaxin, eotaxin-3, TSLP, MCP-4/CCL13), and African American PN patients had lower eosinophils, eotaxin, and eotaxin-3 versus Caucasian and Asian PN patients (p < 0.05 for all). Dupilumab responders had higher AEC (p < 0.01), were more likely to be Caucasian (p = 0.02) or Asian (p = 0.05) compared to African Americans, and more often had a history of atopy (p = 0.08). This study suggests that blood AEC > 0.3 K and Asian and Caucasian races are associated with Th2 skewed circulating immune profiles and response to Th2 targeted therapies.

Clinical Characteristics and Treatment Outcomes of Prurigo Nodularis: A Retrospective Study

BACKGROUND

Prurigo nodularis (PN) is a complex chronic skin disease characterized by severe pruritic nodules. PN is often associated with mental health disorders and chronic medical comorbidities. Until recently, PN treatment has been challenging and difficult.

OBJECTIVES

This study aims to describe the demographic, clinical characteristics, and comorbidities associated with PN. Also, we aim to describe the effectiveness of systemic therapies, including methotrexate, cyclosporine, and narrow band ultraviolet (NB-UVB) in adult patients with PN.

METHODS

This is a retrospective chart review of adult patients diagnosed with PN at Hamilton Health Science Center and/or McMaster University in Hamilton, Ontario, between 2015 and 2023.

RESULTS

The study included 81 patients (57% female). The mean age was 52.8 years, and the mean age of PN diagnosis was 50 years. Reported symptoms included: itching (100%), dry skin (53%), pain (17%), and burning sensation (5%). Lower and upper extremities were the most common areas involved in 93% and 69%, respectively. Mental health disorders were present in 79% of patients, with depression (58%) and anxiety (52%) being the most common. Atopic dermatitis was the most common skin comorbidity noted. Treatments used included cyclosporine, and NB-UVB, and MTX, which resulted in significant improvement of pruritus in 38%, 35%, and 31% of patients, respectively, at week 16.

CONCLUSIONS

PN is associated with increased risk of mental health disorders and other medical comorbidities. Cyclosporine, methotrexate, and NB-UVB therapy may be effective treatment options, however clinicians must consider the potential short- and long-term adverse effects of these treatments.

Dysregulation of the Skin-Liver Axis in Prurigo Nodularis: An Integrated Genomic, Transcriptomic, and Population-Based Analysis

Pruritus has long been linked to hepatic dysfunction; however, there are limited data characterizing the association between liver disease and prurigo nodularis (PN), a chronic inflammatory skin disease featuring severe pruritis. We thus conducted a cross-sectional analysis of hepatic comorbidities in PN patients using TriNetX, a large global health research network. This analysis revealed that PN patients had a higher risk (p < 0.001) of developing liver cirrhosis, acute and subacute hepatic failure, inflammatory liver disease, chronic hepatitis, nonalcoholic steatohepatitis, portal hypertension, fatty liver, chronic passive congestion of the liver, and hepatocellular carcinoma compared with healthy controls. The cumulative incidence of liver disease was about three times higher in PN patients compared with healthy controls. These findings provided the basis for translational studies to investigate a genetic mechanism for this association. Cutaneous transcriptomic analysis performed on PN patients revealed the dysregulation of genes related to hepatic failure in lesional PN compared with both nonlesional PN and control skin. Similarly, gene set variation analysis (GSVA) revealed a significantly increased (p < 0.05) activation of liver metabolism, chronic hepatic failure, acute hepatic failure, cholestatic liver disease, polycystic liver disease, and hepatocellular carcinoma pathways in lesional PN compared with control skin. A subsequent genome-wide association study (GWAS) identified shared single-nucleotide polymorphisms (SNPs) in the genes AR, EDIL3, MACROD2, PCSK5, RUNX1T1, TENM4, and ZEB2 between PN and liver disease from the FinnGen cohort. Significant dysregulation of the skin-liver axis in PN patients may explain the increased incidence and severity of hepatic comorbidities and help identify future therapeutic targets for PN.

Clinical utility of peripheral blood laboratory testing in the diagnostic workup of prurigo nodularis: A multicenter cohort study

Background

Prurigo nodularis (PN) is a chronic inflammatory skin disease associated with several systemic comorbidities. However, there is lack of evidence supporting specific laboratory testing in the diagnostic workup of PN patients.

Objective

To characterize the frequency and severity of clinical laboratory abnormalities in PN patients compared to controls.

Methods

Cross-sectional study of adult patients between October, 2015 and August, 2021 using TriNetX, a global health records database encompassing over 74 million patients.

Results

A total of 12,157 PN patients were matched to 12,157 controls. Significantly, greater proportions of PN patients had moderate-to-severely decreased hemoglobin, elevated transaminases, decreased albumin, increased bilirubin, increased serum creatinine, decreased estimated glomerular filtration rate, higher hemoglobin A1c levels, and alterations in thyroid stimulating hormone.

Limitations

Our data identifies associated laboratory abnormalities in PN patients but is unable to support a causal relationship.

Conclusion

PN patients are more likely to have laboratory abnormalities on renal, hepatic, hematologic, endocrine, and metabolic laboratory testing, demonstrating a role for systemic testing in the diagnostic workup of PN patients.

Risk of incident sleep disorders in patients with prurigo nodularis: A population-level analysis using The Health Improvement Network

Background

Prurigo nodularis (PN) is a chronic inflammatory skin condition characterized by severely itchy and often painful bumps on the arms, legs, and trunk. It is unknown whether patients with PN have increased risk of developing sleep disorders.

Objective

To evaluate the association of PN with sleep disorders.

Methods

This retrospective, population-level, matched-cohort study was conducted using The Health Improvement Network. The study included 4193 patients with newly diagnosed PN and 4193 age, sex, and race/ethnicity-matched controls. A Cox regression model was used to assess the development of sleep disorders, including insomnia, sleep apnea, and restless legs syndrome, in patients with PN compared with control patients.

Results

Compared with controls, PN was associated with insomnia (adjusted hazard ratio [aHR] = 1.77; 95% CI = 1.48-2.12) and overall sleep disorder (aHR = 1.72; 95% CI = 1.46-2.02), but not with sleep apnea (aHR = 1.51; 95% CI = 0.93-2.44) or restless legs syndrome (aHR = 1.54; 95% CI = 0.92-2.57).

Limitations

As a retrospective cohort study, our analysis is subject to potential confounders not already included.

Conclusions

PN was associated with subsequent development of insomnia. Thus, clinicians should consider insomnia among patients with PN and develop strategies for treatment and prevention.

Incident Comorbidity, Resource Use, and All-Cause Mortality Associated with Prurigo Nodularis: A United Kingdom Retrospective Database Analysis

We described comorbidity, resource utilization, and mortality for patients with prurigo nodularis (PN) using data from the Clinical Practice Research Datalink. Patients with incident PN (2008-2018) were selected and matched to controls. Of 2,416 patients with PN, 2,409 (99.7%) were matched to controls. Prevalence of atopic dermatitis (relative risk [RR] = 2.571; 95% confidence interval [CI] = 2.356-2.806), depression (RR = 1.705; 95% CI = 1.566-1.856), anxiety (RR = 1.540; 95% CI = 1.407-1.686), coronary heart disease (RR = 1.575; 95% CI = 1.388-1.787), chronic kidney disease (RR = 1.529; 95% CI = 1.329-1.759), and type 2 diabetes mellitus (RR = 1.836; 95% CI = 1.597-2.111) was significantly higher for patients with PN. Subsequent risk of atopic dermatitis (hazard ratio = 6.58; 95% CI = 5.17- 8.37), depression (hazard ratio = 1.61; 95% CI = 1.30-1.99), and coronary heart disease (hazard ratio = 1.37; 95% CI = 1.09-1.74) were significantly increased. Resource utilization was increased in all settings: incidence rate ratio = 1.48 (95% CI = 1.47-1.49) for primary care, incident rate ratio = 1.80 (95% CI = 1.75-1.85) for inpatients, incident rate ratio = 2.15 (95% CI = 2.13-2.18) for outpatients, and incidence rate ratio = 1.32 (95% CI = 1.27-1.36) for accident and emergency. Respective cost ratios were 1.78 (95% CI = 1.67-1.90), 1.52 (95% CI = 1.20-1.94), 2.34 (95% CI = 2.13-2.58), and 1.55 (95% CI = 1.33-1.80). Total primary and secondary healthcare costs were £2,531 versus £1,333, a cost ratio of 1.62 (95% CI = 1.36-1.94). The adjusted hazard ratio for mortality was 1.37 (95% CI = 1.14-1.66). Patients with PN had significantly increased rates of comorbidity, healthcare resources utilization, and mortality compared with matched controls.

Patient Perspectives on Living With Severe Prurigo Nodularis

Importance

Because of a paucity of qualitative research on prurigo nodularis (PN), the symptoms and impacts of PN that are most important to patients are poorly understood.

Objective

To explore patients' perspectives on their PN symptoms and to understand the impacts of the condition.

Design, Setting, and Participants

One-on-one qualitative telephone interviews were held with English-speaking US adults aged 18 years or older with a confirmed diagnosis of PN, severe pruritus, and moderate to severe sleep disturbance. Participants were recruited via patient associations, patient panels, and social media posts. Interviews took place between September 10, 2020, and March 16, 2021.

Main Outcomes and Measures

The main symptoms of PN and their impacts on quality of life were identified by content analysis of deidentified interview transcripts.

Results

A total of 21 adults with PN (mean [SD] age, 53.1 [11.8] years; 15 [71%] female; 2 African American or Black patients [10%], 1 Asian patient [5%], and 18 White patients [86%]; of these, 1 patient [ 5%] had Hispanic or Latino ethnicity) participated in the interviews. All participants reported itch, pain associated with PN, bleeding or scabbing, and dry skin. Other frequently reported symptoms included lumps or bumps (95%), having a crust on the skin (95%), burning (90%), stinging (90%), lesions or sores (86%), skin discoloration (86%), and raw skin (81%). Of the 17 participants who indicated what their worst symptoms were, 15 (88%) identified itching as the worst or 1 of the worst symptoms. The most frequently reported impacts of PN for quality of life were changes in sleep (100%), daily life (100%), feelings or mood (95%), relationships (95%), social life (81%), and work or school (71%). Overall, the worst impact of PN was its association with impaired feelings or mood.

Conclusions and Relevance

This qualitative study suggests the importance of itching, sleep disturbance, and other symptoms and impacts of PN. This information can be used to guide end point selection in clinical trials and to inform patient-centric decision-making in clinical practice.

Phase 3 Trial of Nemolizumab in Patients with Prurigo Nodularis

BACKGROUND

Prurigo nodularis is a chronic, debilitating, and severely pruritic neuroimmunologic skin disease. Nemolizumab, an interleukin-31 receptor alpha antagonist, down-regulates key pathways in the pathogenesis of prurigo nodularis.

METHODS

In this phase 3, double-blind, multicenter, randomized trial, we assigned adults with moderate-to-severe prurigo nodularis to receive an initial 60-mg dose of nemolizumab followed by subcutaneous injections of 30 mg or 60 mg (depending on baseline weight) every 4 weeks for 16 weeks or matching placebo. The primary end points were an itch response (a reduction of ≥4 points on the Peak Pruritus Numerical Rating Scale [PP-NRS; scores range from 0 to 10, with higher scores indicating more severe itch]) and an Investigator's Global Assessment (IGA) response (a score of 0 [clear] or 1 [almost clear] on the IGA [scores range from 0 to 4] and a reduction from baseline to week 16 of ≥2 points). There were five key secondary end points.

RESULTS

A total of 274 patients underwent randomization; 183 were assigned to the nemolizumab group, and 91 to the placebo group. Treatment efficacy was shown with respect to both primary end points at week 16; a greater percentage of patients in the nemolizumab group than in the placebo group had an itch response (56.3% vs. 20.9%; strata-adjusted difference, 37.4 percentage points; 95% confidence interval [CI], 26.3 to 48.5), and a greater percentage in the nemolizumab group had an IGA response (37.7% vs. 11.0%; strata-adjusted difference, 28.5 percentage points; 95% CI, 18.8 to 38.2) (P<0.001 for both comparisons). Benefits were observed for the five key secondary end points: itch response at week 4 (41.0% vs. 7.7%), PP-NRS score of less than 2 at week 4 (19.7% vs. 2.2%) and week 16 (35.0% vs. 7.7%), and an improvement of 4 or more points on the sleep disturbance numerical rating scale (range, 0 [no sleep loss] to 10 [unable to sleep at all]) at week 4 (37.2% vs. 9.9%) and week 16 (51.9% vs. 20.9%) (P<0.001 for all comparisons). The most common individual adverse events were headache (6.6% vs. 4.4%) and atopic dermatitis (5.5% vs. 0%).

CONCLUSIONS

Nemolizumab monotherapy significantly reduced the signs and symptoms of prurigo nodularis. (Funded by Galderma; ClinicalTrials.gov number, NCT04501679; EudraCT number, 2019-004789-17.).

Validation of the Peak Pruritus Numerical Rating Scale as a Patient-Reported Outcome Measure in Prurigo Nodularis

INTRODUCTION

Validated patient report tools for quantifying patient experiences of itch in prurigo nodularis (PN) are limited. This study aimed to evaluate the validity of the 11-point peak pruritus numerical rating scale (PP NRS) as a single-item patient-reported outcome (PRO) measure for assessing itch severity in PN.

METHODS

Content validity of the PP NRS was evaluated through qualitative interviews with adults with PN. The PP NRS was then psychometrically evaluated using data from a placebo-controlled trial of nemolizumab in adults with PN, during which patients completed the PP NRS daily. Meaningful within-patient change was estimated from the qualitative interviews and by anchor- and distribution-based analyses of trial data.

RESULTS

The interview participants (N = 21) all understood the PP NRS and reported itch as their worst symptom overall. The PP NRS showed good test-retest reliability and demonstrated convergent validity and known-groups validity. PP NRS scores improved more in patients classified as "improved" on other clinical outcome measures than in those classified as "worsened/unchanged". Triangulation of the different estimates identified a 2- to 5-point decrease in PP NRS score as a meaningful within-patient change threshold.

CONCLUSION

The PP NRS is a content-valid and reliable PRO measure for quantifying itch severity in adults with PN in clinical trials.

TRIAL REGISTRATION NUMBER

NCT03181503.

Somatic mutations reveal hyperactive Notch signaling and racial disparities in prurigo nodularis

Prurigo nodularis (PN) is a chronic inflammatory skin disease that disproportionately affects African Americans and is characterized by pruritic skin nodules of unknown etiology. Little is known about genetic alterations in PN pathogenesis, especially relating to somatic events which are often implicated in inflammatory conditions. We thus performed whole-exome sequencing on 54 lesional and nonlesional skin biopsies from 17 PN patients and 10 atopic dermatitis (AD) patients for comparison. Somatic mutational analysis revealed that PN lesional skin harbors pervasive somatic mutations in fibrotic, neurotropic, and cancer-associated genes. Nonsynonymous mutations were most frequent in NOTCH1 and the Notch signaling pathway, a regulator of cellular proliferation and tissue fibrosis, and NOTCH1 mutations were absent in AD. Somatic copy-number analysis, combined with expression data, showed that recurrently deleted and downregulated genes in PN lesional skin are associated with axonal guidance and extension. Follow-up immunofluorescence validation demonstrated increased NOTCH1 expression in PN lesional skin fibroblasts and increased Notch signaling in PN lesional dermis. Finally, multi-center data revealed a significantly increased risk of NOTCH1-associated diseases in PN patients. In characterizing the somatic landscape of PN, we uncover novel insights into its pathophysiology and identify a role for dysregulated Notch signaling in PN.

Modulation of Neuroimmune and Epithelial Dysregulation in Patients With Moderate to Severe Prurigo Nodularis Treated With Nemolizumab

Importance

Prurigo nodularis (PN) is a debilitating skin disease characterized by intense pruritus and hyperkeratotic skin nodules. Nemolizumab, a monoclonal antibody targeting interleukin 31 receptor α, is a promising novel therapy for the treatment of moderate to severe PN. The biological mechanisms by which nemolizumab promotes improvement of itch and skin lesions in PN are unknown.

Objective

To characterize changes in plasma protein biomarkers associated with clinical response to nemolizumab in patients with PN.

Design, Setting, and Participants

This multicenter cohort study included patients recruited from Austria, France, Germany, Poland, and the US from a phase 2 clinical trial. Adults diagnosed with moderate to severe PN with severe pruritus for at least 6 months were included in the original trial. Patients in the nemolizumab group were included in the present study if they achieved at least a 4-point decrease in the Peak Pruritus Numerical Rating Scale (PP-NRS) from baseline to week 12 during nemolizumab treatment. Placebo controls did not experience a 4-point decrease in PP-NRS. Mass spectrometry with tandem mass tags to enrich skin-specific protein detection was used to characterize changes in plasma protein expression in nemolizumab and placebo groups. Data were collected from November 2, 2017, to September 26, 2018, and analyzed from December 6, 2019, to April 8, 2022.

Intervention

As part of the clinical trial, patients were treated with 3 doses of nemolizumab or placebo at 0, 4, and 8 weeks.

Main Outcomes and Measures

Changes in plasma and epidermal protein expression in nemolizumab-treated patients compared with the placebo group at 0, 4, and 12 weeks.

Results

Among the 38 patients included in the analysis (22 women and 16 men; mean [SD] age, 55.8 [15.8] years), enrichment analysis of canonical pathways, biological functions, and upstream regulators showed downregulation of terms involving inflammation (IL-6, acute-phase response, signal transducer and activator of transcription 3, and interferon γ), neural processes (synaptogenesis signaling and neuritogenesis), tissue remodeling and fibrosis (transforming growth factor β1 and endothelin-1), and epidermal differentiation (epithelial mesenchymal transition) in the plasma of nemolizumab group.

Conclusions and Relevance

In this cohort study, differences between nemolizumab and placebo groups included modulation of inflammatory signaling, neural development, and epithelial differentiation, suggesting a promising potential approach for clinical management of PN.

Cutaneous neuropeptides: the missing link between psychological stress and chronic inflammatory skin disease?

A "brain-skin" connection has been long been observed between chronic stress and chronic inflammatory skin disease including urticaria, psoriasis, atopic dermatitis, and prurigo nodularis. The relationship appears to be bidirectional. Chronic psychological stress has been shown to sustain hyperactivity of the sympathetic branch of the autonomic nervous system. Chronic stress is proinflammatory and in the context of several dermatologic disorders may be associated with an increase in dermal nerve fiber density, mast cells, nerve growth factor and calcitonin-gene-related peptide (CGRP). Furthermore, CGRP elicits a TH2-polarized T-cell response that is a hallmark of chronic pruritic conditions such as atopic dermatitis and prurigo nodularis. This TH2 response contributes directly to acute pruritus as well as the sensitization of cutaneous sensory neurons that are critical for chronic pruritus. Prurigo nodularis is a debilitating skin disorder featuring prominent nerve structural, neuropeptide, and TH2 cytokine aberrations that is a model deserving of future study.

The Sleep Disturbance Numerical Rating Scale: Content Validity, Psychometric Validation, and Meaningful Within-Patient Change in Prurigo Nodularis

INTRODUCTION

Sleep is often disturbed in patients with prurigo nodularis (PN). To address the lack of validated patient-reported outcome (PRO) measures for quantifying sleep disturbance in PN, we evaluated the Sleep Disturbance Numerical Rating Scale (SD NRS) as a single-item PRO measure for quantifying sleep disturbance in PN.

METHODS

Adults with PN participated in qualitative interviews, which included concept elicitation and cognitive debriefing of the SD NRS. The SD NRS was evaluated psychometrically using data from a phase 2 randomized trial in adults with PN (NCT03181503). Other PRO assessments included the Average Pruritus (AP) NRS, AP Verbal Rating Scale (VRS), peak pruritus (PP) NRS, PP VRS, and Dermatology Life Quality Index (DLQI). Reliability, validity, and responsiveness of the SD NRS were evaluated, and meaningful within-patient change was estimated from qualitative interview responses and quantitative trial data.

RESULTS

All interview participants (N = 21) experienced sleep disturbance and most (95%) understood the SD NRS as intended. The SD NRS demonstrated test-retest reliability based on intra-class correlation coefficients for itch-stable participants of 0.87 for the AP VRS and 0.76 for the PP VRS. At baseline, Spearman's rank-order correlation coefficients were moderate to strong (0.3-0.8) between the SD NRS and the AP NRS, AP VRS, PP NRS, PP VRS, and DLQI. Known-groups validity was demonstrated by higher (worse) SD NRS scores in participants with worse scores on the AP NRS, AP VRS, PP VRS, and DLQI. Improvements in SD NRS scores were greater in participants classified as "improved" versus "worsened/unchanged" on the anchor PROs. A 2- to 4-point decrease on the 11-point SD NRS scale was identified as a meaningful within-patient change.

CONCLUSION

The SD NRS is a well-defined, reliable, and valid PRO measure that can be used in daily practice and clinical trials to capture sleep disturbance in adults with PN.

The blood proteomic signature of prurigo nodularis reveals distinct inflammatory and neuropathic endotypes: A cluster analysis

BACKGROUND

Prurigo nodularis (PN) is an extremely pruritic, chronic inflammatory skin disease. Little is known about systemic inflammation in PN.

OBJECTIVE

To characterize plasma inflammatory biomarkers in patients with PN and investigate the presence of disease endotypes.

METHODS

In this cross-sectional study, Olink proteomic analysis was performed on plasma samples from patients with PN (n = 29) and healthy controls (n = 18).

RESULTS

Patients with PN had increased levels of 8 circulating biomarkers compared to controls, including tumor necrosis factor, C-X-C Motif Chemokine Ligand 9, interleukin-12B, and tumor necrosis factor receptor superfamily member 9 (P < .05). Two PN clusters were identified in cluster 1 (n = 13) and cluster 2 (n = 16). Cluster 2 had higher levels of 25 inflammatory markers than cluster 1. Cluster 1 had a greater percentage of patients with a history of myelopathy and spinal disc disease compared with cluster 2 (69% vs 25%, P = .03). Patients in cluster 2 were more likely to have a history of atopy (38% in cluster 2 vs 8% in cluster 1, P = .09).

LIMITATIONS

Small sample size precludes robust subgroup analyses.

CONCLUSION

This study provides evidence of neuroimmune-biased endotypes in PN and can aid clinicians in managing patients with PN that are nonresponsive to traditional therapies.

Single-cell RNA sequencing reveals dysregulated fibroblast subclusters in prurigo nodularis

Prurigo nodularis (PN) is an intensely pruritic, chronic inflammatory skin disease that disproportionately affects black patients. However, the pathogenesis of PN is poorly understood. We performed single-cell transcriptomic profiling, ligand receptor analysis and cell trajectory analysis of 28,695 lesional and non-lesional PN skin cells to uncover disease-identifying cell compositions and genetic characteristics. We uncovered a dysregulated role for fibroblasts (FBs) and myofibroblasts as a key pathogenic element in PN, which were significantly increased in PN lesional skin. We defined seven unique subclusters of FBs in PN skin and observed a shift of PN lesional FBs towards a cancer-associated fibroblast (CAF)-like phenotype, with WNT5A+ CAFs increased in the skin of PN patients and similarly so in squamous cell carcinoma (SCC). A multicenter PN cohort study subsequently revealed an increased risk of SCC as well as additional CAF-associated malignancies in PN patients, including breast and colorectal cancers. Systemic fibroproliferative diseases were also upregulated in PN patients, including renal sclerosis and idiopathic pulmonary fibrosis. Ligand receptor analyses demonstrated increased FB1-derived WNT5A and periostin interactions with neuronal receptors MCAM and ITGAV, suggesting a fibroblast-neuronal axis in PN. Type I IFN responses in immune cells and increased angiogenesis/permeability in endothelial cells were also observed. As compared to atopic dermatitis (AD) and psoriasis (PSO) patients, increased mesenchymal dysregulation is unique to PN with an intermediate Th2/Th17 phenotype between atopic dermatitis and psoriasis. These findings identify a pathogenic role for CAFs in PN, including a novel targetable WNT5A+ fibroblast subpopulation and CAF-associated malignancies in PN patients.

Circulating plasma IL-13 and periostin are dysregulated type 2 inflammatory biomarkers in prurigo nodularis: A cluster analysis

Importance

Prurigo nodularis (PN) is a chronic heterogeneous inflammatory skin disease.

Objective

To elucidate which components of type 2 inflammation are dysregulated systemically in PN.

Design

Whole blood was obtained from PN patients with uncontrolled disease and control patients without pruritus. Plasma was assayed for IL-4, IL-5, IL-13, IgE, and periostin. ANOVA was utilized to compare PN and control patients and multiple-hypothesis adjusted p-value was calculated with the significance threshold at 0.05. Clustering was performed using K-means clustering.

Participants

PN patients (n = 29) and controls (n = 18) from Johns Hopkins Dermatology had similar age sex, and race distributions.

Results

Single-plex assays of the biomarkers demonstrated elevated circulating plasma IL-13 (0.13 vs. 0.006 pg/mL, p = 0.0008) and periostin (80.3 vs. 60.2 ng/mL, p = 0.012) in PN compared to controls. IL-4 (0.11 vs. 0.02 pg/mL, p = 0.30) and IL-5 (0.75 vs. 0.40 pg/mL, p = 0.10) were not significantly elevated, while IgE approached significance (1202.0 vs. 432.7 ng/mL, p = 0.08). Clustering of PN and control patients together revealed two clusters. Cluster 1 (n = 36) consisted of 18 PN patients and 18 controls. Cluster 2 (n = 11) consisted entirely of PN patients (p < 0.01). Cluster 2 had higher levels of IL-13 (0.33 vs. 0.008 pg/mL, p = 0.0001) and IL-5 (1.22 vs. 0.43 pg/mL, p = 0.03) compared to cluster 1.

Conclusion and relevance

This study demonstrates elevation of IL-13 and periostin in the blood of PN patients, with distinct clusters with varying degrees of type 2 inflammation. Given this heterogeneity, future precision medicine approaches should be explored in the management of PN.

The Impact of ADHD on Maternal Quality of Life

Childhood attention-deficit/hyperactivity disorder (ADHD) is associated with substantial burden to caregiver quality of life (QoL). However, a paucity of work has focused on quantifying QoL among caregivers of adolescents with a history of ADHD. The purpose of the current study was (1) to quantify maternal QoL in a sample of mothers of adolescents with and without childhood ADHD; and (2) to examine predictors (i.e., parent and child characteristics and behavior) associated with maternal QoL. Participants included mothers of adolescents with (N = 110) and without ADHD (N = 90) ranging in age from 13 to 18 (M = 16.09, 92% male). The Quality Adjusted Life-Year (QALY) was used to calculate maternal QoL using two health domains (i.e., anxiety/depression and disruption in daily activities) commonly impacted by raising youth with ADHD. QALYs are valued monetarily to estimate disease burden. Mothers of adolescents with childhood ADHD experienced significantly worse QoL relative to mothers in the comparison group. Maternal depression, as well as adolescent age, ADHD status, and discipline problems significantly predicted lower levels of maternal QALY health status index, with ADHD being the strongest predictor. This is equal to a reduction in 1.96 QALYs when summed over the course of a child's lifetime and is associated with a loss of $98,000 to $196,000. Results of the investigation help to further elucidate the health impacts incurred by families of adolescents with ADHD and have important public health implications. Further, parental QoL should be considered when conceptualizing the financial and negative health impact of ADHD.

Acupuncture for the Treatment of Itch: Peripheral and Central Mechanisms

Despite the widespread clinical use of acupuncture in the treatment of pruritus caused by psoriasis, urticaria, uremic, and other diseases, insights into the mechanism of action of acupuncture are still emerging. For the above reasons, a beneficial effect of acupuncture on pruritus was not recommended or reported in recent clinical practice guidelines. Acupuncture is a kind of physical stimulation, which has the characteristics of multi-channel and multi-target effects. The biomechanical stimulation signal of acupuncture needling can be transformed into bioelectric and chemical signals; interfere with kinds of cells and nerve fibers in the skin and muscle; alter signaling pathways and transcriptional activity of cells, mediators, and receptors; and result in inhibition of peripheral and central transmission of pruritus. Available mechanistic data give insights into the biological regulation potency of acupuncture for pruritus and provide a basis for more in-depth and comprehensive mechanism research.

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.

Cluster analysis of circulating plasma biomarkers in prurigo nodularis reveals a distinct systemic inflammatory signature in African Americans

Patients with prurigo nodularis (PN) suffer from intractable itch and dramatic reduction in quality of life. While there is significant clinical heterogeneity in the presentation of PN, disease endotypes remain unknown. We assayed circulating plasma cytokine concentrations in PN patients (n=20) along with matched healthy controls and utilized an unsupervised machine learning algorithm to identify disease endotypes. We found two distinct clusters of PN patients with non-inflammatory (Cluster 1) and inflammatory (Cluster 2) plasma profiles. Cluster 2 had more African-Americans (82%, n=9 vs. 33%, n=3; P=0.028), higher worst-itch numeric rating scale scores (9.5±0.9 vs. 8.3±1.2; P=0.036), and lower quality of life as reflected by higher Dermatology Life Quality Index scores (21.9±6.4 vs. 13.0±4.1; P=0.015). In addition, Cluster 1 had a higher rate of myelopathy (67%, n=6 vs. 18%, n=2; P=0.028). Compared to Cluster 1, Cluster 2 had higher levels of IL-1α, IL-4, IL-5, IL-6, IL-10, IL-17A, IL-22, IL-25, and IFN-α. With population-level analysis, African-American PN patients had higher erythrocyte sedimentation rate, C-reactive protein, ferritin, eosinophils, and lower transferrin than Caucasian PN patients. These findings indicate discrete clusters of PN patients with plasma biomarker profiles corresponding to distinct demographic and clinical characteristics, potentially allowing for precision medicine approaches to treat PN.