Direct and Indirect Effects of Crisaborole Ointment on Quality of Life in Patients with Atopic Dermatitis: A Mediation Analysis

Kappa opioid agonists in the treatment of itch: just scratching the surface?

Chronic pruritus is a debilitating condition affecting 23-44 million Americans. Recently, kappa opioid agonists (KOAs) have emerged as a novel class of potent antipruritic agents. In 2021, the Food and Drug Administration approved difelikefalin (Korsuva) for the treatment of moderate-to-severe pruritus associated with chronic kidney disease in adults undergoing hemodialysis. Difelikefalin is a potent, peripherally restricted KOA that is intravenously available. Although promising, difelikefalin is currently available as an intravenous composition only, limiting the scope of use. Oral formulations of difelikefalin did not meet the primary endpoint criteria in recent phase 2 clinical trials; however, additional clinical studies are ongoing. The future for KOAs in the treatment of pruritus is encouraging. Orally active pathway-biased KOAs, such as triazole 1.1, may serve as viable alternatives with broader applications. Extended-release compositions, such as the TP-2021 ProNeura subdermal implant, may circumvent the pharmacokinetic issues associated with peptide-based KOAs. Lastly, dual-acting kappa opioid receptor agonist/mu opioid receptor antagonists are orally bioavailable and may be useful in the treatment of various forms of chronic itch. In this review, we summarize the results of KOAs in clinical and preclinical trials and discuss future directions of drug development.

Crisaborole efficacy in murine models of skin inflammation and Staphylococcus aureus infection

Phosphodiesterase 4 (PDE4) is highly expressed in keratinocytes and immune cells and promotes pro-inflammatory responses upon activation. The activity of PDE4 has been attributed to various inflammatory conditions, leading to the development and approval of PDE4 inhibitors as host-directed therapeutics in humans. For example, the topical PDE4 inhibitor, crisaborole, is approved for the treatment of mild-to-moderate atopic dermatitis and has shown efficacy in patients with psoriasis. However, the role of crisaborole in regulating the immunopathogenesis of inflammatory skin diseases and infection is not entirely known. Therefore, we evaluated the effects of crisaborole in multiple mouse models, including psoriasis-like dermatitis, AD-like skin inflammation with and without filaggrin mutations, and Staphylococcus aureus skin infection. We discovered that crisaborole dampens myeloid cells and itch in the skin during psoriasis-like dermatitis. Furthermore, crisaborole was effective in reducing skin inflammation in the context of filaggrin deficiency. Importantly, crisaborole reduced S. aureus skin colonization during AD-like skin inflammation. However, crisaborole was not efficacious in treating S. aureus skin infections, even as adjunctive therapy to antibiotics. Taken together, we found that crisaborole reduced itch during psoriasis-like dermatitis and decreased S. aureus skin colonization upon AD-like skin inflammation, which act as additional mechanisms by which crisaborole dampens the immunopathogenesis in mouse models of inflammatory skin diseases. Further examination is warranted to translate these preclinical findings to human disease.

Clinical and Humanistic Burden of Atopic Dermatitis in Europe: Analyses of the National Health and Wellness Survey

Introduction

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease that negatively impacts overall health, quality of life (QoL), and work productivity. Prior studies on AD burden by severity have focused on moderate-to-severe disease. Here, we describe the clinical and humanistic burden of AD in Europe across all severity levels, including milder disease.

Methods

Data were analyzed from the 2017 National Health and Wellness Survey from adult respondents with AD in the EU-5 (France, Germany, Italy, Spain, and the UK). AD disease severity was defined based on self-reported assessments as “mild,” “moderate,” or “severe” and by Dermatology Life Quality Index (DLQI) severity bands. Self-reported outcomes for AD respondents by severity were assessed using propensity score matching. These outcomes included a wide range of selected medical/psychological comorbidities, overall QoL and functional status (EuroQol 5-Dimensions 5-Level and Short Form-36 version 2 questionnaires), and work productivity and activity impairment (Work Productivity and Activity Impairment questionnaire).

Results

In total, 4208 respondents with AD (mild AD, 2862; moderate AD, 1177; severe AD, 169) and 4208 respondents without AD were included in this analysis. Results showed greater burden across severity levels compared with matched non-AD controls. A higher proportion of respondents with mild-to-moderate AD, defined by DLQI severity bands, reported atopic comorbidities (P < 0.05) and a wide range of cardiac, vascular, and metabolic comorbidities, including hypertension, high cholesterol, angina, and peripheral vascular disease (P < 0.005), compared with non-AD controls. Relative to potential impacts of various medical and psychological burdens, respondents with mild-to-moderate AD reported higher activity impairment than controls (P < 0.0001).

Conclusion

Clinical and humanistic burden was observed in European respondents with AD compared with matched non-AD controls across severity levels, with burden evident even in milder disease, highlighting the importance of improving disease management in early stages of AD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-022-00700-6.

Chronic itch: emerging treatments following new research concepts

Until recently, itch pathophysiology was poorly understood and treatments were poorly effective in relieving itch. Current progress in our knowledge of the itch processing, the numerous mediators and receptors involved has led to a large variety of possible therapeutic pathways. Currently, inhibitors of IL-31, IL-4/13, NK₁ receptors, opioids and cannabinoids, JAK, PDE4 or TRP are the main compounds involved in clinical trials. However, many new targets, such as Mas-related GPCRs and unexpected new pathways need to be also explored.

Current Clinical Options for the Management of Itch in Atopic Dermatitis

Pruritus is the most burdensome and prevalent symptom in patients suffering from atopic dermatitis. Treating atopic itch has historically been a challenge due to multiple underlying mechanisms within its pathogenesis and an incomplete understanding of them. In recent years, our understanding of these mechanisms have increased tremendously and subsequently, new treatments have reached the market that target the pathophysiology of atopic itch from different angles. In addition, there are several promising new treatments currently in development and trials. In the current article, we discuss these currently available treatment options, their available evidence and efficacy, and highlight some of the more recent advancements in the field.

Relationship Among Treatment, Pruritus, Investigator's Static Global Assessment, and Quality of Life in Patients with Atopic Dermatitis

Introduction

The Investigator’s Static Global Assessment (ISGA) is a 5-point rating scale that is recommended by the US Food and Drug Administration for assessing the severity of atopic dermatitis (AD), and ISGA success is a widely used endpoint in AD clinical studies. In this study, we seek to interpret the relationship of ISGA with treatment, pruritus, and quality of life (QoL) by conducting post hoc analyses of pooled data from two phase 3 crisaborole studies.

Methods

Patients aged ≥ 2 years with baseline ISGA of 2 (mild) or 3 (moderate) were randomly assigned 2:1 to receive crisaborole or vehicle for 28 days. Disease severity, pruritus severity, and QoL were assessed with the ISGA, Severity of Pruritus Scale (SPS), and Dermatology Life Quality Index (DLQI; patients aged ≥ 16 years), or Children’s Dermatology Life Quality Index (CDLQI; patients aged 2–15 years), respectively. The effect of treatment on ISGA and the relationship between ISGA and QoL were analyzed using a longitudinal repeated-measures model. The interrelationship between treatment, disease severity, pruritus, and QoL was analyzed with a mediation model.

Results

Overall, 1522 patients (crisaborole, n = 1016; vehicle, n = 506) were included. Estimated longitudinal profiles indicated changes in ISGA by day 8 were large for crisaborole (effect size [ES]: − 0.68) and small for vehicle (ES: − 0.34). There was a direct relationship between ISGA and DLQI and CDLQI severity bands in the longitudinal repeated-measures model. For both QoL mediation models, treatment effects on QoL were mediated indirectly by reduction in pruritus (DLQI, 42.4%; CDLQI, 58.1%) and disease severity (DLQI, 12.2%; CDLQI, 33.1%).

Conclusions

These post hoc analyses suggest that ISGA success is a clinically meaningful endpoint associated with reduction in the severity of pruritus and improvement in QoL.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13555-021-00506-y.