607 Anti-pruritic properties of remetinostat (SHAPE), a topical histone deacetylase inhibitor (HDACi); data from a randomized phase 2 study in patients with stage IA- IIA mycosis fungoides

Emerging drugs for the treatment of cutaneous T-cell lymphoma

INTRODUCTION

Cutaneous T cell lymphoma (CTCL) is a rare and incurable group of non-Hodgkin lymphomas that manifests as patches, plaques, tumors, and/or erythroderma in the skin. Standard skin-directed therapies for CTCL are effective in patients with indolent early-stage disease but more advanced/refractory stage patients require systemic therapies. However, none of the treatments are considered curative and most patients suffer from relapses. Biologic therapies and immunotherapy provide novel treatment options for patients with advanced or refractory disease.

AREAS COVERED

This review provides a discussion of recently approved biological and novel therapeutics that are actively developed for the management of the heterogenous group of CTCL.

EXPERT OPINION

Mogamulizumab and brentuximab vedotin have reached the market and are approved for the treatment of CTCL, providing valuable options. Additionally, therapies utilizing immune checkpoint inhibitors, miRNA inhibitors, and peptide inhibitors show promising results in clinical trials. Durvalumab, pembrolizumab, TTI-621, BNZ-1, and MRG-106 are several of the emerging treatments still in trials. Further combinatorial studies are needed as none of the treatments have demonstrated long term remissions.

Current status of histone deacetylase inhibitors in cutaneous T-cell lymphoma

Cutaneous T cell lymphoma (CTCL) is a non-Hodgkin's lymphoma with a heterogenous presentation and highly variable disease course. The most common subtypes of CTCL are mycosis fungoides (MF) and Sézary Syndrome (SS). Treatment varies based on the stage of the disease with skin directed therapies typically utilized for early stage disease, and systemic therapies employed for more advanced disease. There are few highly effective treatments available, and systemic therapies have limited response rates. Histone deacetylase inhibitors have emerged as mainstream treatments for MF/SS over the past several years. Here, we discuss the mechanism of action of histone deacetylase inhibitors in relation to the pathogenesis of MF/SS, evaluate the clinical trials that led to Food and Drug Administration approval of two of the histone deacetylase inhibitors for MF/SS and describe the results for those still under investigation. Additionally, we discuss the potential for combination therapies in order to optimize outcomes of treatment with histone deacetylase inhibitors.

Skin Cutibacterium acnes Mediates Fermentation to Suppress the Calcium Phosphate-Induced Itching: A Butyric Acid Derivative with Potential for Uremic Pruritus

Pruritus and inflammation associated with accumulation of calcium phosphate (CaP) under the skin are common problems among dialysis patients with chronic kidney disease (CKD). The role of skin commensal microbiota in the CaP-induced uremic pruritus remains uncharacterized. Skin Cutibacterium acnes (C. acnes) can solubilize CaP by the production of short-chain fatty acids (SCFAs), such as butyric acid, through glucose fermentation. Like butyric acid, the N-[2-(2-Butyrylamino-ethoxy)-ethyl]-butyramide (BA-NH-NH-BA), a butyric acid derivative, remarkably induced acetylation of histone H3 lysine 9 (AcH3K9) in keratinocytes. Topical application of fermenting C. acnes, butyric acid or BA-NH-NH-BA onto mouse skin effectively ameliorated CaP-induced skin itching, interleukin (IL)-6 up-regulation in keratinocytes, and extracellular signal-regulated kinase (ERK) 1/2 activation in dorsal root ganglia (DRG). Activation of ERK 1/2 by CaP was markedly reduced in IL-6 knockout mice. Genus Cutibacterium was detected in relatively low abundance in itchy skin of patients with CKD. Our results identify a role for the skin fermenting C. acnes in ameliorating CaP-induced activation of IL-6/p-ERK signaling and resulting skin inflammation. Furthermore, we provide evidence for the potential therapeutic efficacy of BA-NH-NH-BA as a postbiotic for the treatment of uremic pruritus.

Research Techniques Made Simple: An Introduction to Drug Discovery for Dermatology

This article aims to provide an overview of drug discovery with a focus on application within dermatology. The term "drug" can be used to describe a wide variety of agents, including small molecules, cell therapies, and antibodies, which may be dosed intravenously, orally, topically, or by other routes of administration. We summarize the economics and risks involved in drug discovery. Understanding the needs of patients and clinicians through use of a target product profile before initiating drug discovery can reduce time and effort spent developing a poor or unneeded drug. For small molecule drug discovery, a chemical starting point is then required. We present four options for finding a chemical starting point for drug discovery projects: screening libraries of compounds or modifying, reformulating, or repositioning a known drug. Examples of each technique's use in dermatology are provided. We also describe the subsequent steps involved in discovery of a new drug. To help interested readers, we provide information on how to engage with academic drug discovery centers or industrial partners.