Aprepitant improves refractory pruritus in primary cutaneous T-cell lymphomas: experience of the Spanish Working Group on Cutaneous Lymphomas

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.

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 changing therapeutic landscape, burden of disease, and unmet needs in patients with cutaneous T-cell lymphoma

Cutaneous T-cell lymphomas (CTCLs) have a chronic, relapsing course, and the most common subtypes are mycosis fungoides and Sézary syndrome. The disease causes visible skin alterations and can also cause alopecia, pruritus and pain, all of which can impact patients' health-related quality of life (HRQoL). The goal of treatment is to reduce symptoms and prevent disease progression. However, treatment recommendations are often based on low levels of evidence due to the lack of well-designed randomised clinical trials and treatment guidelines, and approved drugs vary considerably across different countries and regions. Currently, available treatments rarely lead to durable remissions and eventually become less effective, meaning patients often require multiple therapy changes. Skin-directed therapies (SDTs) are first-line treatments for early-stage CTCL, whereas systemic therapies may be needed for early-stage disease that does not respond to SDT or for advanced-stage disease. However, patients can experience significant side-effects with these treatments or may be unable to tolerate them. Hence, there is an unmet need for effective therapies with good safety profiles for the treatment of early- and late-stage CTCL. Here, we review current treatment guidelines, investigational and approved treatments, the impact of CTCL on patients' HRQoL, and the treatment of pruritus.

Neurokinin-1 Receptor Antagonists as Anticancer Drugs

Background::

Human tumor cells lines and tumor samples overexpress the neurokinin-1 receptor (NK-1R). Substance P (SP), after binding to NK-1Rs, induces tumor cell proliferation, an antiapoptotic effect and promotes angiogenesis and the migration of cancer cells for invasion and metastasis.

Methods: :

In contrast, NK-1R antagonists block the previous pathophysiological actions mediated by SP. These antagonists promote the death of tumor cells by apoptosis. Peptide and non-peptide NK-1R antagonists have been reported.

Results: :

Peptide NK-1R antagonists show chemical modifications of the SP molecule (L-amino acids being replaced by D-amino acids), whereas non-peptide NK-1R antagonists include numerous compounds with different chemical compositions while showing similar stereochemical features (affinity for the NK- 1R). Currently, there are more than 300 NK-1R antagonists.

Conclusion::

In combination therapy with classic cytostatics, NK-1R antagonists have additive or synergic effects and minimize the side-effects of cytostatics. The effect of NK-1R antagonists as broad-spectrum anticancer drugs is reviewed and the use of these antagonists for the treatment of cancer is suggested.

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.

Emerging Treatments and Novel Pathways in Pruritus

Itch treatment is a major challenge in the dermatologist’s practice. We encounter patients suffering from pruritus on a regular basis, and often lack diverse treatment options to adequately respond to the patients’ needs. In the last 20 years, novel pathways have been investigated that were beyond the scope of histamine. Although most did not result in a molecule available on the Canadian market, it is interesting and important as health care providers to stay up to date with new neuronal pathways involved in itch transmission and potential new therapeutic options. In this review, we will discuss pathways targeted in new topical treatments such as antagonist of proteinase-activated receptor-2, the endocannabinoid system, neurotrophins and tropomyosin-related kinase A receptor, the transient receptor potential-vanilloid or transient receptor potential-melastatine ion channels. New systemic therapies are now focusing on antagonizing the neurokinin receptor, modulating the opioidergic system, or targeting itch cytokines such as interleukin-31.