Clinical profile of patients with acute generalized pustular psoriasis with and without IL36RN mutations in multi-ethnic Johor Bahru, Malaysia

Asia-Pacific consensus recommendations on the management of generalized pustular psoriasis

Generalized pustular psoriasis (GPP) is a rare, chronic, heterogeneous, and potentially life-threatening disease characterized by primary, sterile, and macroscopically visible pustules with or without systemic symptoms. There are ethnic differences in the genetic mutations associated with GPP that might affect the clinical manifestations and treatment responses. Currently, there is limited evidence from the patient population in the Asia-Pacific (APAC) region, resulting in a general paucity of information on the effective management of patients with GPP in this region. This modified Delphi panel study aimed to identify current evidence and gain advanced insights to facilitate the development of a regionally tailored APAC consensus on the management of GPP. A systematic literature review (SLR) was conducted to identify published literature and develop consensus statements on (i) definition and clinical course, (ii) diagnosis of GPP, (iii) treatment outcomes, goals, and monitoring measures, and (iv) optimal management strategies and clinical practices. Statements were rated by a panel of dermatologists in two rounds, with the threshold for consensus at ≥80% agreement. Twenty experts from the APAC region reached consensus on 106 statements that were developed based on the SLR and experts' collective expertise. The experts agreed that GPP is a rare, severe, and potentially life-threatening condition that is distinct from plaque psoriasis. This consensus emphasized the importance of a tailored treatment strategy taking into account the GPP flare severity and each patient's unique clinical circumstances. The experts reached consensus on the severity classification of GPP flares and recommended first-line and maintenance treatment options for adult GPP, childhood GPP, and GPP in pregnancy. These consensus outcomes have been synthesized into treatment algorithms to guide dermatologists in the APAC region in their clinical decision-making processes.

Targeted review of IL36RN mutations in patients with generalised pustular psoriasis

Background

Generalised pustular psoriasis (GPP) is a rare and chronic skin disease historically treated with therapies that were originally intended to treat plaque psoriasis (PsO). However, GPP and plaque PsO have distinct pathogeneses and clinical courses.

Objectives

This study aimed to further characterise the unique genetic background of GPP by summarising evidence on the frequency and type of IL36RN gene mutation, a gene that normally suppresses proinflammatory responses, in patients with GPP compared to patients with GPP and plaque PsO, and patients with plaque PsO only.

Methods and Results

A targeted literature review was conducted to identify studies reporting IL36RN mutations and/or HLA-Cw6 allele frequency in patients with GPP. Meta-analyses showed a significantly higher rate of IL36RN mutations in the GPP-only population compared to the GPP + plaque PsO population (OR 3.51; 95% CI 2.29, 5.38). Monoallelic mutations of IL36RN were found in up to 33.3%, and biallelic mutations in up to 73.2% of patients with GPP (GPP-only and GPP + plaque PsO), in contrast with mono- and biallelic frequencies of only 0%-11.9% and 0%, respectively, in patients with plaque PsO only. Mean age-of-onset ranged from 5.9 to 48.9 years old, with most studies reporting a GPP age-of-onset between 20 and 40 years old. Twenty-one mutations were identified in the biallelic state and three in monoallelic. The most reported mutations were c.115 + 6T > C (p. Arg10ArgfsX1) (18 studies); c.227 C > T (p.Pro76Leu) (10 studies); and c.338 C > T (p.Ser113Leu) (8 studies). Mutations varied depending on geography and ethnicity, with the most frequently reported mutation predominantly reported in East Asian studies and international studies that included Asian patients. Rates of HLA-Cw6, the risk allele most strongly associated with plaque PsO, were 0%-28.6% for patients with GPP, similar to rates in the general population (10.5%-20%).

Conclusion

Considering the differences between GPP and plaque PsO in aetiology and disease symptoms, effective, GPP-specific treatment options are needed, and recent research suggests that blockade of IL-36 signalling may be an effective target for treatment of GPP.

Clinical advances in biological therapy for generalized pustular psoriasis: a review

INTRODUCTION

In 2022, U.S. Food and Drug Administration (FDA) approved the first biologics, intravenous spesolimab, for acute flare of generalized pustular psoriasis (GPP). The drug works by blocking IL-36 signaling, the key pathway of GPP. Among the known mutations causing GPP, IL36RN mutations are most common, and the presence of IL36RN mutations had been found to affect the clinical manifestations and treatment response of GPP.

AREAS COVERED

Literature search was conducted in PubMed, Embase and ClinicalTrials.gov for relevant studies discussing biologic treatment for GPP with special emphasis on larger studies, pediatric group, pregnant women, and the influence of IL36RN mutation on the effectiveness of biologics.

EXPERT OPINION

The approval of spesolimab for GPP flare treatment marks a new era. However, whether spesolimab will be placed as the treatment of choice remains unknown, considering its higher cost, lack of direct comparison with existing biologics, and uncertain effects on co-existing plaque-type psoriasis. However, the demonstration of numerically better efficacy for patients carrying pathogenic IL36RN mutations suggests the role of pharmacogenetics in the choices of GPP treatment. Future randomized studies are warranted to investigate the effectiveness and safety of biologics for GPP in pediatric and pregnant groups.

Characteristics of Patients Experiencing a Flare of Generalized Pustular Psoriasis: A Multicenter Observational Study

Background: Generalized pustular psoriasis (GPP) is a rare, severe inflammatory skin disease characterized by recurrent episodes of flares. Characteristics of patients experiencing a flare are hardly described in a real-life setting. The aim of the study is to investigate the clinical characteristics of patients experiencing a flare of GPP. Methods: Multicenter retrospective observational study on consecutive patients experiencing a flare of GPP between 2018 and 2022. Disease severity and quality of life were assessed by Generalized Pustular Psoriasis Area, Body Surface Area (BSA), and Severity Index (GPPASI), and Dermatology life quality index (DLQI) questionnaire, respectively. Visual analogue scale (VAS) of itch and pain, triggers, complications, comorbidities, pharmacological therapies, and outcome were collected. Results: A total of 66 patients, 45 (68.2%) females, mean age 58.1 ± 14.9 years, were included. The GPPASI, BSA, and DLQI were 22.9 ± 13.5 (mean ± standard deviation), 47.9 ± 29.1, and 21.0 ± 5.0, respectively. The VAS of itch and pain were 6.2 ± 3.3 and 6.2 ± 3.0, respectively. Fever (>38 °C) and leukocytosis (WBC > 12 × 109/L) were found in 26 (39.4%) and 39 (59.1%) patients, respectively. Precipitating triggers were identified in 24 (36.3%) and included infections (15.9%), drugs (10.6%), stressful life events (7.6%), and corticosteroids withdrawal (3.0%). Fourteen (21.2%) patients were hospitalized because of complications including infections in 9 (13.6%) leading to death in one case and hepatitis in 3 (4.5%). Conclusions: GPP flares can be severe and cause severe pain and itch with significant impact on the quality of life. In about one-third of patients the flare may have a persistent course and, with complications, lead to hospitalization.