Which is the Ideal JAK Inhibitor for Alopecia Areata - Baricitinib, Tofacitinib, Ritlecitinib or Ifidancitinib - Revisiting the Immunomechanisms of the JAK Pathway

Unraveling Ritlecitinib: an in-depth analysis of JAK3 inhibitor for the treatment of alopecia areata

INTRODUCTION

Alopecia Areata (AA), characterized by non-scarring hair loss due to the dysregulation of the JAK/STAT pathway, has long lacked effective treatment. In 2023, Ritlecitinib, a novel Janus kinase (JAK) 3 and tyrosine kinase family inhibitor, received its first approval from the US FDA to treat AA, followed by approvals in Japan, Europe, China, and the UK. This development aims to address the challenges faced by millions of individuals affected by this condition globally.

AREAS COVERED

This review offers an overview of Ritlecitinib's pharmacological properties, biological targets, and development strategies. It examines its mechanism of action, pharmacokinetics, pharmacodynamics, and clinical trial insights. Additionally, it covers the drug's chemical synthesis, contraindications, drug interactions, and potential adverse effects, with special attention to its use in adolescents, pregnant women, and the elderly.

EXPERT OPINION

Ritlecitinib represents a significant advancement in treating AA, offering a targeted approach with promising efficacy and a favorable safety profile. While long-term safety data and real-world effectiveness studies are needed, its oral administration and efficacy in both adults and adolescents position it as a potentially transformative therapy. Ongoing research should focus on optimizing treatment strategies, identifying predictive biomarkers, and assessing cost-effectiveness to fully realize Ritlecitinib's potential in improving outcomes.

Role of Cytokines and Chemokines in Vitiligo and Their Therapeutic Implications

Vitiligo is a persistent autoimmune disease characterized by progressive depigmentation of the skin caused by the selective destruction of melanocytes. Although its etiopathogenesis remains unclear, multiple factors are involved in the development of this disease, from genetic and metabolic factors to cellular oxidative stress, melanocyte adhesion defects, and innate and adaptive immunity. This review presents a comprehensive summary of the existing knowledge on the role of different cellular mechanisms, including cytokines and chemokines interactions, in the pathogenesis of vitiligo. Although there is no definitive cure for vitiligo, notable progress has been made, and several treatments have shown favorable results. A thorough understanding of the basis of the disease uncovers promising drug targets for future research, providing clinical researchers with valuable insights for developing improved treatment options.

Nano-based formulations of thymoquinone are new approaches for psoriasis treatment: a literature review

Psoriasis, a persistent immune-mediated inflammatory skin condition, affects approximately 2-3% of the global population. Current treatments for psoriasis are fraught with limitations, including adverse effects, high costs, and diminishing efficacy over time. Thymoquinone (TQ), derived from Nigella sativa seeds, exhibits promising anti-inflammatory, antioxidant, and immunomodulatory properties that could prove beneficial in managing psoriasis. However, TQ's hydrophobic nature and poor bioavailability have hindered its usefulness as a therapeutic agent. Recent research has strategically addressed these challenges by developing nano-thymoquinone (nano-TQ) formulations to enhance delivery and efficacy in treating psoriasis. Preclinical studies employing mouse models have demonstrated that nano-TQ effectively mitigates inflammation, erythema, scaling, epidermal thickness, and cytokine levels in psoriatic lesions. Various nano-TQ formulations, including nanoemulsions, lipid vesicles, nanostructured lipid carriers, and ethosomes, have been explored to improve solubility, facilitate skin penetration, ensure sustained release, and achieve site-specific targeting. Although clinical trials are currently scarce, the outcomes from in vitro and animal models are promising. The potential co-delivery of nano-TQ with other anti-psoriatic agents also presents avenues for further investigation.

Computational insights into rational design and virtual screening of pyrazolopyrimidine derivatives targeting Janus kinase 3 (JAK3)

The Janus kinase 3 (JAK3) family, particularly JAK3, is pivotal in initiating autoimmune diseases such as rheumatoid arthritis. Recent advancements have focused on developing antirheumatic drugs targeting JAK3, leading to the discovery of novel pyrazolopyrimidine-based compounds as potential inhibitors. This research employed covalent docking, ADMET (Absorption, Distribution, Metabolism, Excretion, Toxicity) analysis, molecular dynamics modeling, and MM/GBSA (Molecular Mechanics Generalized Born Surface Area) binding free energy techniques to screen 41 in silico-designed pyrazolopyrimidine derivatives. Initially, 3D structures of the JAK3 enzyme were generated using SWISS-MODEL, followed by virtual screening and covalent docking via AutoDock4 (AD4). The selection process involved the AMES test, binding affinity assessment, and ADMET analysis, narrowing down the candidates to 27 compounds that passed the toxicity test. Further covalent docking identified compounds 21 and 41 as the most promising due to their high affinity and favourable ADMET profiles. Subsequent development led to the creation of nine potent molecules, with derivatives 43 and 46 showing exceptional affinity upon evaluation through molecular dynamics simulation and MM/GBSA calculations over 300 nanoseconds, comparable to tofacitinib, an approved RA drug. However, compounds L21 and L46 demonstrated stable performance, suggesting their effectiveness in treating rheumatoid arthritis and other autoimmune conditions associated with JAK3 inhibition.

Interleukin-15 is a hair follicle immune privilege guardian

The autoimmunity-promoting cytokine, Interleukin-15 (IL-15), is often claimed to be a key pathogenic cytokine in alopecia areata (AA). Yet, rhIL-15 promotes human hair follicle (HF) growth ex vivo. We have asked whether the expression of IL-15 and its receptor (IL-15R) isoforms is altered in human AA and how IL-15 impacts on human HF immune privilege (HF-IP) in the presence/absence of interferon-γ (IFNγ), the well-documented key AA-pathogenic cytokine, as well as on hair regrowth after experimental AA induction in vivo. Quantitative immunohistomorphometry showed the number of perifollicular IL-15+ T cells in AA skin biopsies to be significantly increased compared to healthy control skin, while IL-15, IL-15Rα, and IL-15Rγ protein expression within the hair bulb were significantly down-regulated in AA HFs. In organ-cultured human scalp HFs, rhIL-15 significantly reduced hair bulb expression of MICA, the key "danger" signal in AA pathogenesis, and increased production of the HF-IP guardian, α-MSH. Crucially, ex vivo, rhIL-15 prevented IFNγ-induced HF-IP collapse, restored a collapsed HF-IP by IL-15Rα-dependent signaling (as documented by IL-15Rα-silencing), and protected AA-preventive immunoinhibitory iNKT10 cells from IFNγ-induced apoptosis. rhIL-15 even promoted hair regrowth after experimental AA induction in human scalp skin xenotransplants on SCID/beige mice in vivo. Our data introduce IL-15 as a novel, functionally important HF-IP guardian whose signaling is constitutively defective in scalp HFs of AA patients. Our data suggest that selective stimulation of intrafollicular IL-15Rα signaling could become a novel therapeutic approach in AA management, while blocking it pharmacologically may hinder both HF-IP restoration and hair re-growth and may thus make HFs more vulnerable to AA relapse.

Revealing innovative JAK1 and JAK3 inhibitors: a comprehensive study utilizing QSAR, 3D-Pharmacophore screening, molecular docking, molecular dynamics, and MM/GBSA analyses

The heterocycle compounds, with their diverse functionalities, are particularly effective in inhibiting Janus kinases (JAKs). Therefore, it is crucial to identify the correlation between their complex structures and biological activities for the development of new drugs for the treatment of rheumatoid arthritis (RA) and cancer. In this study, a diverse set of 28 heterocyclic compounds selective for JAK1 and JAK3 was employed to construct quantitative structure-activity relationship (QSAR) models using multiple linear regression (MLR). Artificial neural network (ANN) models were employed in the development of QSAR models. The robustness and stability of the models were assessed through internal and external methodologies, including the domain of applicability (DoA). The molecular descriptors incorporated into the model exhibited a satisfactory correlation with the receptor-ligand complex structures of JAKs observed in X-ray crystallography, making the model interpretable and predictive. Furthermore, pharmacophore models ADRRR and ADHRR were designed for each JAK1 and JAK3, proving effective in discriminating between active compounds and decoys. Both models demonstrated good performance in identifying new compounds, with an ROC of 0.83 for the ADRRR model and an ROC of 0.75 for the ADHRR model. Using a pharmacophore model, the most promising compounds were selected based on their strong affinity compared to the most active compounds in the studied series each JAK1 and JAK3. Notably, the pharmacokinetic, physicochemical properties, and biological activities of the selected compounds (As compounds ZINC79189223 and ZINC66252348) were found to be consistent with their therapeutic effects in RA, owing to their non-toxic, cholinergic nature, absence of P-glycoprotein, high gastrointestinal absorption, and ability to penetrate the blood-brain barrier. Furthermore, ADMET properties were assessed, and molecular dynamics and MM/GBSA analysis revealed stability in these molecules.

A Real-World Study of Steroid-Free Monotherapy with Tofacitinib in Severe and Therapy-Recalcitrant Alopecia Areata, Alopecia Totalis, and Alopecia Universalis Cases: A Retrospective Analysis

Background

Alopecia areata (AA) presents with noncicatricial alopecia and has multifactorial etiology. Janus Kinase inhibitors (JAKibs) with potential efficacy and favorable side-effect profile are the first class of drugs to receive FDA approval in AA.

Objectives

Our primary objective was to assess the complete response rates to tofacitinib monotherapy in severe and recalcitrant AA, alopecia totalis (AT), and alopecia universalis (AU) patients using the latest percentage change in Severity of alopecia tool (SALT) score. We also aimed to analyze the various systemic agents used by these patients prior to the use of tofacitinib.

Materials and Methods

Institutional records of 17 patients with severe or refractory AA, AT, and AU treated with tofacitinib monotherapy were analyzed, retrospectively. The response to tofacitinib therapy was determined after calculating percentage change in SALT score. End of treatment was defined as the dose which resulted in a significant response (complete/near complete response was ≥75% hair regrowth from baseline as determined by SALT score).

Results

Majority of patients had severe AA (SALT ≥ 50) (n = 9/17, 52.94%), while five patients had AT and three had AU. All patients had received either systemic glucocorticoids (GCS), which included oral mini pulse (OMP) (n = 8), intravenous pulse steroids (n = 4), and daily oral GCS (n = 6) or immunosuppressive agents (ISAs) which included cyclosporine (n = 14) followed by methotrexate (n = 6) and azathioprine (n = 6). Mean SALT score prior to starting tofacitinib was 74.23. Mean dose of tofacitinib used was 13.23 mg (10-15 mg) and mean duration of treatment was 9.23 months. Latest percentage change of SALT score ranged from 70.58% to 100%, with an average of 91.47%. Most patients showed complete/near complete response (13/17, 76.47%).

Conclusion

Tofacitinib was found to be safe and effective in severe/refractory AA, AU, and AT patients recalcitrant to other treatment modalities in our study. Further studies are needed to assess the effect of these targeted drugs on JAK-STAT expression or tissue cytokines involved in the pathogenesis of AA using immunohistochemistry.

Fresh Baked: An Overview of Newly FDA-Approved Drugs for Dermatological Usage

With our better understanding of the pathogenesis of various diseases, more and more drugs and biological products are being tried and tested every day. Roughly, around 40-50 novel drugs get approved by the Food and Drug Administration (FDA) for use in the general population, making it difficult for a physician to keep track of the constant changes in therapy. This article aimed to provide a compilation of all the FDA-approved new drugs for dermatological conditions and new dermatological indications of known drugs in the recent past, especially for dermatology residents and practising dermatologists. A comprehensive analysis, based on the list of new molecular entities approved by the FDA from 2020 to 2023, as well as a thorough English language literature search from 2020 to July 2023 across multiple databases (PubMed, MEDLINE, Springer Nature, Google Scholar and Cochrane) for various keywords (alone and in combination) such as "FDA approved" OR "recent advances in therapy" OR "recent drugs" OR "novel treatment" OR "dermatology," was performed. All data extracted were incorporated into the present compilation. A total of 33 drugs, including newly approved and newly approved indications of previously known drugs, were found. Relevant information about them has been discussed in a tabulated manner. This article provides an at a glance summarised profile of the newly FDA-approved drugs, as available in the existing literature. However, with the astonishing rate of new drugs hitting the market, more and more clinical trials are required to ensure the rational use of these agents.