Aprepitant for the Treatment of Pruritus in Sézary Syndrome: A Randomized Crossover Clinical Trial

What's New in Cutaneous T-Cell Lymphoma-Associated Pruritus

Cutaneous T-cell lymphomas are a heterogenous group of lymphomas that cause various skin manifestations. Severe pruritus occurs frequently in cutaneous T-cell lymphoma and negatively impacts patients' quality of life. The pathophysiology of cutaneous T-cell lymphoma-associated itch is complex and involves various immune cells, inflammatory cytokines, and neuroimmune interactions. Treating cutaneous T-cell lymphoma pruritus can be challenging, and there have been few randomized controlled studies evaluating the use of antipruritic treatments in these patients. Systemic therapies targeting the disease have also been shown to have some antipruritic effects. Furthermore, although biologic therapy has revolutionized the treatment of other pruritic skin conditions, the use of biologics in cutaneous T-cell lymphoma remains controversial.

An update on mechanisms of pruritus and their potential treatment in primary cutaneous T-cell lymphoma

Primary cutaneous T-cell lymphomas (CTCL), which include mycosis fungoides (MF) and Sézary syndrome (SS), are a group of lymphoproliferative disorders characterized by clonal accumulation of neoplastic T-lymphocytes in the skin. Severe pruritus, one of the most common and distressing symptoms in primary CTCL, can significantly impair emotional well-being, physical functioning, and interpersonal relationships, thus greatly reducing quality of life. Unfortunately, effectively managing pruritus remains challenging in CTCL patients as the underlying mechanisms are, as of yet, not fully understood. Previous studies investigating the mechanisms of itch in CTCL have identified several mediators and their corresponding antagonists used for treatment. However, a comprehensive overview of the mediators and receptors contributing to pruritus in primary CTCL is lacking in the current literature. Here, we summarize and review the mediators and receptors that may contribute to pruritus in primary CTCL to explore the mechanisms of CTCL pruritus and identify effective therapeutic targets using the PubMed and Web of Science databases. Studies were included if they described itch mediators and receptors in MF and SS. Overall, the available data suggest that proteases (mainly tryptase), and neuropeptides (particularly Substance P) may be of greatest interest. At the receptor level, cytokine receptors, MRGPRs, and TRP channels are most likely important. Future drug development efforts should concentrate on targeting these mediators and receptors for the treatment of CTCL pruritus.

EORTC consensus recommendations for the treatment of mycosis fungoides/Sézary syndrome - Update 2023

On behalf of the EORTC Cutaneous Lymphoma Tumours Group (EORTC-CLTG) and following up on earlier versions published in 2006 and 2017 this document provides an updated standard for the treatment of mycosis fungoides and Sézary syndrome (MF/SS). It considers recent relevant publications and treatment options introduced into clinical practice after 2017. Consensus was established among the authors through a series of consecutive consultations in writing and a round of discussion. Treatment options are assigned to each disease stage and, whenever possible and clinically useful, separated into first- and second line options annotated with levels of evidence. Major changes to the previous version include the incorporation of chlormethine, brentuximab vedotin, and mogamulizumab, recommendations on the use of pegylated interferon α (after withdrawal of recombinant unpegylated interferons), and the addition of paragraphs on supportive therapy and on the care of older patients. Still, skin-directed therapies are the most appropriate option for early-stage MF and most patients have a normal life expectancy but may suffer morbidity and impaired quality of life. In advanced disease treatment options have expanded recently. Most patients receive multiple consecutive therapies with treatments often having a relatively short duration of response. For those patients prognosis is still poor and only for a highly selected subset long term remission can be achieved with allogeneic stem cell transplantation. Understanding of the disease, its epidemiology and clinical course, and its most appropriate management are gradually advancing, and there is well-founded hope that this will lead to further improvements in the care of patients with MF/SS.

Chronic pruritus: from pathophysiology to drug design

Pruritus, the most common symptom in dermatology, is an innate response capable of protecting skin against irritants. Nonetheless, when it lasts more than six weeks it is assumed to be a chronic pathology having a negative impact on people's lives. Chronic pruritus (CP) can occur in common and rare skin diseases, having a high prevalence in global population. The existing therapies are unable to counteract CP or are associated with adverse effects, so the development of effective treatments is a pressing issue. The pathophysiological mechanisms underlying CP are not yet completely dissected but, based on current knowledge, involve a wide range of receptors, namely neurokinin 1 receptor (NK1R), Janus kinase (JAK), and transient receptor potential (TRP) ion channels, especially transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1). This review will address the relevance of these molecular targets for the treatment of CP and molecules capable of modulating these receptors that have already been studied clinically or have the potential to possibly alleviate this pathology. According to scientific and clinical literature, there is an increase in the expression of these molecular targets in the lesioned skin of patients experiencing CP when compared with non-lesioned skin, highlighting their importance for the development of potential efficacious drugs through the design of antagonists/inhibitors.

Comparison of aprepitant versus desloratadine for EGFR-TKI-induced pruritus: A randomized phase 2 clinical trial

BACKGROUND

Pruritus is one of the most common and challenging side effects of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) and has impaired patients' quality of life and treatment compliance. Our study evaluated the efficacy and safety of aprepitant in managing EGFR-TKIs-related pruritus.

METHODS

This randomized, double-blind, placebo-controlled study was conducted between December 2016 and August 2020 in China. Patients were eligible if they were 18 years or older and had histologically confirmed locally advanced or metastatic non-small cell lung cancer (NSCLC) with first onset of moderate to severe pruritus during EGFR-TKI treatment.

RESULTS

A total of 130 eligible patients were randomly assigned to aprepitant (n = 65) or desloratadine (n = 65) groups. The median (interquartile range [Q1, Q3]) age was 63 (54, 70) years, and 79 (60.8%) were women. Mean visual analog scale scores at baseline were 6.35 (95% confidence interval [CI], 5.89-6.82) in the aprepitant group and 5.94 (95% CI, 5.56-6.32) in the desloratadine group. After 1 week of treatment, 33 (53.2%) patients responded to aprepitant, which was significantly higher than that of 14 (23.7%) patients responded to desloratadine (p = .001). Moreover, patients in the aprepitant group had a significantly shorter response time than patients in the desloratadine group (mean [days], 13.39 [95% CI, 11.08-15.70] vs. 16.67 [95% CI, 14.19-19.13], p = .04). The most frequent drug-related adverse events in aprepitant group and desloratadine were constipation and dry mouth, and all adverse events were grade 1-2.

CONCLUSIONS

To the authors' knowledge, this is the first study to prospectively present that aprepitant elicited a better and faster response and mild toxicity for managing EGFR-TKI induced pruritus than desloratadine.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02646020.

Neurokinin 1 Receptor Antagonists for Pruritus

Pruritus, commonly known as itch, is a very common symptom in numerous dermatological disorders and systemic diseases. It can manifest as acute, or when lasting longer than 6 weeks, it is considered chronic and can lead to significant distress and reduced quality-of-life of those suffering. Current therapeutics are limited and are lacking in efficacy, and the development of more effective treatments is needed. The neurokinin 1 receptor (NK1R) antagonists are a novel class of drugs that possess several properties such as antidepressant, anxiolytic and antiemetic activities. Recently, several studies have described the antipruritic activity of NK1R antagonists for treating chronic pruritus. In this review we outline the pathogenesis of chronic pruritus, the mechanism by which the neuropeptide substance P (SP) and its receptor NK1R may be targeted to inhibit pruritic activity, and the efficacy and tolerability of NK1R antagonists, which have been, or are currently being investigated for treating conditions where chronic pruritus is a major symptom. Increasing evidence from ongoing and completed studies demonstrates the importance of SP and NK1R signalling in mediating pruritic activity. Several NK1R antagonists have shown significant antipruritic activity and thus targeting the SP-NK1R pathway may provide a therapeutic option for treating chronic pruritus of certain origin/s in the foreseeable future.

Benefits and harms of NK1 R antagonists in pruritus: A systematic review and meta-analysis

Accumulating evidence has showed the possibility of using NK1R antagonists for the treatment of chronic pruritus. However, the benefit and risk profile of NK1R antagonists-serlopitant and aprepitant for the treatment of pruritus remains unclear. To assess the efficacy and safety of NK1R antagonists-serlopitant and aprepitant in patients with pruritus based on analysis of clinical trials. The current systematic review and meta-analysis was performed according to PRISMA guidelines. A total of 10 randomized clinical trials including 631 patients were enrolled. Four randomized controlled trials investigated the comparative treatment effect of serlopitant on pruritus. Our results showed that serlopitant had reasonable anti-pruritic effectiveness in patients, with mild toxicities. The overall proportion of 4-point improvement of NRS and VAS in serlopitant-treatment group were both significantly higher relative to placebo group (OR 2.345, 95%CI 1.557 to 3.531, P < .001; OR 3.308, 95% CI 1.949 to 5.616, P < .001). Serlopitant treatment was also found to be associated with a significant reduction in NRS score as compared with placebo (SMD -0.381, 95%CI -0.599 to -0.164, P = .001). Six clinical trials reported the treatment effect of aprepitant on pruritus. The meta-analysis result of fixed-effect model showed that there was no significant difference between aprepitant and controlled treatment in terms of improved pruritus VAS score (SMD -0.088, 95%CI -0.384 to 0.207, P = .558). There is promising high-quality evidence regarding the efficacy of serlopitant on pruritus. More large-sample randomized controlled trials with appropriate treatment regimen are urgently needed to further evaluate the effectiveness of aprepitant in pruritus.

The Neurokinin-1 Receptor Antagonist Aprepitant: An Intelligent Bullet against Cancer?

Neurokinin-1 receptor (NK-1R) antagonists exert antitumor action, are safe and do not cause serious side-effects. These antagonists (via the NK-1R) exert multiple actions against cancer: antiproliferative and anti-Warburg effects and apoptotic, anti-angiogenic and antimetastatic effects. These multiple effects have been shown for a broad spectrum of cancers. The drug aprepitant (an NK-1R antagonist) is currently used in clinical practice as an antiemetic. In in vivo and in vitro studies, aprepitant also showed the aforementioned multiple antitumor actions against many types of cancer. A successful combination therapy (aprepitant and radiotherapy) has recently been reported in a patient suffering from lung carcinoma: the tumor mass disappeared and side-effects were not observed. Aprepitant could be considered as an intelligent bullet against cancer. The administration of aprepitant in cancer patients to prevent recurrence and metastasis after surgical procedures, thrombosis and thromboembolism is discussed, as is the possible link, through the substance P (SP)/NK-1R system, between cancer and depression. Our main aim is to review the multiple antitumor actions exerted by aprepitant, and the use of this drug is suggested in cancer patients. Altogether, the data support the reprofiling of aprepitant for a new therapeutic use as an antitumor agent.

Emerging drugs for the treatment of chronic pruritic diseases

INTRODUCTION

Chronic pruritus is non-histaminergic and mediated through a complex interplay of peripheral and central immune and neural pathways. Significant developments in the understanding of chronic pruritus have emerged and paved the way for new, emerging therapies.

AREAS COVERED

This review details the emerging drug landscape for chronic pruritus treatment, focusing on monoclonal antibody agents that target key cytokines and their receptors as well as small molecule agents that inhibit mediators of the immune and neural pathways. The article provides background regarding the currently available therapies and the rationale for the development of new agents based on the current market and recent scientific developments.

EXPERT OPINION

Identification of new targets along neuroimmune itch pathways has allowed for the development of targeted drugs which can be utilized for effective therapy. As we enter a new era of chronic itch treatments, we face exciting prospects and challenges.

Phase 2 trial of a neurokinin-1 receptor antagonist for the treatment of chronic itch in patients with epidermolysis bullosa: A randomized clinical trial

BACKGROUND

Chronic pruritus causes major morbidity in epidermolysis bullosa (EB). The substance P-neurokinin 1 receptor (SP-NK1) pathway is a promising target for treating EB-related pruritus.

OBJECTIVE

To evaluate the safety and efficacy of the oral NK1 receptor antagonist serlopitant in treating moderate-severe pruritus in EB.

METHODS

The study randomized 14 patients to serlopitant or placebo for 8 weeks, followed by a 4-week washout and optional open-label extension. The primary end point was change in itch as measured by the Numeric Rating Scale. Secondary end points were change in itch during dressing changes and wound size.

RESULTS

We observed greater itch reduction with serlopitant, equivalent to a 0.64-point comparative reduction on the 11-point Numeric Rating Scale by week 8, although this failed to meet statistical significance (P = .11). More serlopitant patients achieved ≥3-point reduction compared with placebo (43% vs 14%, P = .35). In post hoc analysis excluding 1 patient with a concurrent seborrheic dermatitis flare, serlopitant achieved significantly greater median itch reduction from baseline by week 4 (-2 points vs 0, P = .01). We observed no statistically significant differences in secondary end points. Serlopitant was well-tolerated.

LIMITATIONS

Small sample size due to disease rarity.

CONCLUSION

The potential itch reduction with serlopitant observed in this trial will be pursued by a larger powered trial (NCT03836001).

NK-1 Receptor Antagonists and Pruritus: Review of Current Literature

The discovery of the first neurokinin 1 (NK-1) receptor antagonist was a turning point in the prevention of chemotherapy-induced nausea and vomiting. The NK-1 antagonists are a novel class of drugs that possess antidepressant, anxiolytic, and antiemetic properties. Recently, clinicians have also described an anti-itch activity of NK-1 antagonists. We present herein results from currently available data on use of NK-1R antagonists in dermatology. For this purpose, a systemic electronic literature search of the PubMed and CINAHL databases, Cochrane Library, and clinicaltrials.gov website was performed. Based on currently available data, it can be concluded that NK-1 inhibitors show significant antipruritic potential for treatment of chronic pruritus in different dermatological conditions, but further studies are needed to establish the best indications and dosage of these drugs.

Substance P and neurokinin 1 receptor are new targets for the treatment of chronic pruritus

BACKGROUND

Chronic pruritus is a distressing symptom associated with various dermatological conditions and systemic diseases. Current treatment options are often inadequate, resulting in impaired quality of life for many patients. An understanding of the underlying mechanisms of itch across pruritic conditions is important for development of effective, targeted treatments for chronic pruritus.

OBJECTIVES

To provide an overview of the pathogenesis of chronic pruritus, focusing on the role of substance P (SP) and neurokinin 1 receptor (NK₁ R) in itch signalling, and to describe data supporting NK₁ R antagonism as a potential strategy for the treatment of chronic pruritus.

METHODS

A PubMed search was conducted to determine what data were available that investigated the role of SP and NK₁ R in itch signalling.

RESULTS

SP is a neuropeptide that is a mediator of itch signalling. One of the target receptors for SP is NK₁ R, which is expressed in the central nervous system and on multiple cell types involved in the initiation and transmission of itch. Studies demonstrating that SP and NK₁ R are overexpressed across multiple chronic itch-inducing conditions and that NK₁ R antagonism disrupts itch signalling and reduces itch provide a rationale for targeting this pathway as a potential treatment of chronic pruritus across multiple diseases.

CONCLUSIONS

A large and growing body of evidence, including recent phase II clinical studies of NK₁ R antagonists, demonstrate that SP and NK₁ R play an important role in itch signalling. Additional studies are ongoing to further evaluate the use of NK₁ R antagonists for the treatment of chronic pruritus. What's already known about this topic? Chronic pruritus has a significant impact on quality of life. Current treatment options for chronic pruritus are inadequate. Substance P (SP) and neurokinin 1 receptor (NK₁ R) have been shown to play a role in itch signalling, and may be a rational target for addressing chronic pruritus. NK₁ R antagonists are being evaluated as potential treatment for chronic pruritus. What does this study add? This review provides a compilation of the most up-to-date data elucidating the role of SP and NK₁ R in itch signalling, which supports targeting this pathway as a potential treatment of chronic pruritus. NK₁ R antagonism disrupts itch signalling and reduces itch. A summary of the latest data on NK₁ R antagonists in the treatment of pruritus is provided.