JAK inhibitors in dermatology: the road travelled and path ahead, a narrative review

Upadacitinib for the management of bullous pemphigoid coexisting with psoriasis vulgaris: a case report and literature review

Both bullous pemphigoid (BP) and psoriasis are common immune-related dermatological conditions in clinical practice, but the co-occurrence of these two diseases is rare. Currently, there is no consensus on the long-term safe and effective treatment for patients with both BP and psoriasis. JAK inhibitors are emerging as targeted therapeutic drugs that act by inhibiting Janus kinase activity, regulating the JAK/STAT pathway, blocking the transduction pathway of key proinflammatory cytokines, and influencing T-cell differentiation. These cytokines upstream of the JAK/STAT pathway play a pivotal role in the pathogenesis of numerous inflammatory and autoimmune disorders. Upadacitinib, a second-generation JAK inhibitor with high selectivity, demonstrates promising potential.This case report aims to provide a description of the successful treatment of bullous pemphigoid (BP) and psoriasis vulgaris by using upadacitinib, highlighting significant clinical outcomes. Additionally, we aim to analyze the underlying mechanism of upadacitinib in treating these two comorbidities by reviewing relevant literature from both domestic and international sources. Based on our clinical observations, upadacitinib appears to be a promising and well-tolerated therapeutic option for patients with concurrent BP and psoriasis, offering valuable insights for developing appropriate treatment strategies in clinical practice.

Th1 and Th2 cytokine expression in hyperkeratotic chronic hand eczema and the role of Tofacitinib a oral JAK inhibitor

Tissue cytokines in chronic hand eczema (CHE) can predict targeted therapy with novel drugs including JAK inhibitors. Our primary objective was to assess the tissue expression of cytokines of Th1 and Th2 cell lines in CHE patients and to study the efficacy of oral tofacitinib. We recruited patients presenting with recalcitrant CHE. Lesional and non-lesional tissue samples were assessed for Th1(IFN-γ, TNF-α) and Th2 related cytokines (IL-4, IL-13, IL-2,) using real time PCR. Tofacitinib 5 mg twice daily was initiated with 4 weekly assessment and we also noted relapses post therapy.Of 21 refractory hyperkeratotic CHE patients, cytokine analysis was performed in 11 patients which showed upregulation of IL-4 [n = 5/11, 1.87-fold increase], TNF-α (n = 5/11, 5.13-fold) and IFN-γ (n = 6/11, 1.98-fold) as compared to uninvolved skin. All patients (100%) had used topical corticosteroids (TCS) and 4/21 (19%) had failed methotrexate and 2/21 (9.5%) had failed acitretin. Tofacitinib 5 mg twice daily was given in 15/21 patients. The mean time to achieve hand eczema severity index 90 (HECSI 90) was 4 weeks (mean duration of treatment:5.8 months, n = 12). Side effects were observed in 4/12 (33.3%) patients and relapse was noted in 3/12 (25%) patients after a mean duration of 7 months after discontinuation of tofacitinib. Tofacitinib (pan-JAK inhibitor) showed an excellent response in refractory CHE patients with predominant tissue Th1/Th2 cells related cytokine expression.

Case report: Effectiveness of low-dose methotrexate monotherapy in post-essential thrombocythemia myelofibrosis

JAK/STAT pathway signalling is associated with both chronic inflammatory conditions such as psoriasis and haematological malignancies such as the myeloproliferative neoplasms (MPNs). Here we describe a 73yo female patient with a history of chronic plaque psoriasis, post-essential thrombocythemia myelofibrosis (MF) and a quality of life substantially impacted by both conditions. We report that 15 mg oral Methotrexate (MTX) weekly as a monotherapy is well tolerated, provides a substantial clinical improvement for both conditions and significantly improves quality of life. We suggest that the recently identified mechanism of action of MTX as a JAK inhibitor is likely to explain this efficacy and suggest that repurposing MTX for MPNs may represent a clinical- and cost-effective therapeutic option.

Abrocitinib Improved Dupilumab-Resistant Severe Atopic Dermatitis with Comorbid Mild Alopecia Areata in a 12-Year-Old Boy: A Case Report with 1-Year Follow-Up

Atopic dermatitis (AD) may sometimes be comorbid with alopecia areata (AA). However, traditional treatments for AA show limited efficacy. New treatment options, such as dupilumab and Janus kinase inhibitors, have proven efficacy in addressing both AD and AA. This article highlights the challenging case of a 12-year-old boy experiencing severe refractory AD and comorbid AA treated with oral abrocitinib after dupilumab failure with 1-year follow-up. After 3 months of treatment, his skin manifestations improved and the hair completely regenerated. No adverse reactions were observed during the 1-year follow-up period. This case provides evidence of the efficacy and safety of using abrocitinib to treat pediatric patients with both AD and AA.

JAK Inhibitors in Cutaneous T-Cell Lymphoma: Friend or Foe? A Systematic Review of the Published Literature

Cutaneous T-cell lymphomas (CTCLs) are a group of lymphoid neoplasms with high relapse rates and no curative treatment other than allogeneic stem cell transplantation (allo-SCT). CTCL is significantly influenced by disruption of JAK/STAT signaling. Therefore, Janus kinase (JAK) inhibitors may be promising for CTCL treatment. This study is a systematic review aiming to investigate the role of JAK inhibitors in the treatment of CTCL, including their efficacy and safety. Out of 438 initially searched articles, we present 13 eligible ones. The overall response rate (ORR) in the treatment with JAK inhibitors in clinical trials was 11-35%, although different subtypes of CTCL showed different ORRs. Mycosis fungoides showed an ORR of 14-45%, while subcutaneous-panniculitis-like T-cell lymphoma (SPTCL) displayed an ORR ranging from 75% to 100%. Five cases were reported having a relapse/incident of CTCL after using JAK inhibitors; of these, three cases were de novo CTCLs in patients under treatment with a JAK inhibitor due to refractory arthritis, and two cases were relapsed disease after graft-versus-host disease treatment following allo-SCT. In conclusion, using JAK inhibitors for CTCL treatment seems promising with acceptable side effects, especially in patients with SPTCL. Some biomarkers, like pS6, showed an association with better responses. Caution should be taken when treating patients with an underlying autoimmune disease and prior immunosuppression.

Pyrrolo[2,3-D]Pyrimidines as EGFR and VEGFR Kinase Inhibitors: A Comprehensive SAR Review

Tyrosine kinases are implicated in a wide array of cellular physiological processes, including cell signaling. The discovery of the BCR-ABL tyrosine kinase inhibitor imatinib and its FDA approval in 2001 paved the way for the development of small molecule chemical entities of diverse structural backgrounds as tyrosine kinase inhibitors for the treatment of various ailments. Two of the most prominent tyrosine kinases as drug targets are the epidermal growth factor receptor (EGFR) and the vascular endothelial growth factor receptor (VEGFR), as evidenced by the clinical success of their many inhibitors in the drug market. Among several other physiological roles, EGFR regulates epithelial tissue development and homeostasis, while VEGFR regulates tumor-induced angiogenesis. The pyrrolo[2,3-d]pyrimidine nucleus represents a deaza-isostere of adenine, the nitrogenous base of ATP. The recent introduction of many pyrrolo[2,3-d]pyrimidines to the drug market as tyrosine kinase inhibitors makes them a hot topic in the medicinal chemistry research area at the present time. This review article comprehensively sheds light on the structure-activity relationship (SAR) of pyrrolo[2,3-d]pyrimidines as EGFR and VEGFR tyrosine kinase inhibitors, aiming to provide help medicinal chemists in the design of future pyrrolopyrimidine kinase inhibitors.

The pathogenetic role of Th17 immune response in atopic dermatitis

PURPOSE OF REVIEW

As we continue to unravel the pathophysiology and immune mechanisms underlying atopic dermatitis (AD), the emergence of targeted treatments has provided new options for management. Although there are available therapies targeting various immune pathways in AD, the precise pathogenic role of interleukin (IL)-17 in AD pathogenesis remains unclear. The objective of this review is to examine the existing data pertaining to the role of IL-17 in AD and shed light on the potential of targeting this pathway as a therapeutic approach in AD treatment.

RECENT FINDINGS

IL-17 has a dual role of pro-inflammatory and immune protective function, making it an important player in several autoimmune and inflammatory conditions. The extent of IL-17 axis involvement in AD pathogenesis is still debatable. Emerging data show that Th17-related cytokines/chemokines are elevated in skin and sera samples of AD patients, with some articles reporting correlations with disease severity. Particularly increased Th17 signature in specific AD patient subsets, such as Asian-origin or pediatric patients, suggests that certain patients' disease presentations are more predominantly influenced by Th17, and, thus, they may benefit more from Th17 therapeutic targeting approaches. Lack of clinical efficacy with anti-Th17 biologics in AD patients, underscores the need to better elucidate the role of Th17 in AD pathogenesis, along with its utility in therapy.

SUMMARY

The well established role of IL-17 in autoimmune disorders hints for its possible participation in AD disease pathogenesis. Subsequent investigations are needed to assess whether the targeting of specific IL-17 isoforms, homodimers, or heterodimers in specific subpopulations of AD can modify treatment outcomes.

JAK inhibitors in vitiligo: what they hit and what they miss - an immunopathogenesis based exposition of existing evidence

INTRODUCTION

Vitiligo is an autoimmune disorder which presents as depigmented macules due to selective loss of melanocytes. Heightened expression of Janus Kinase Signal transducers and activators of transcription (JAK STAT) pathway, which mediate cytokines action, suggest that targeting this signaling pathway may be an effective option.

AREAS COVERED

A PubMed search was carried out with the broad key words 'JAK,' 'vitiligo' from 2016 to 2023. We also analyzed papers where tissue-based JAK expression was studied, with or without concomitant treatment with JAK inhibitors. We address the role of JAK inhibitors in vitiligo and their effect on repigmentation of lesions.

EXPERT OPINION

While JAK inhibitors help in cessation of disease progression, they have no in vivo action on melanocyte proliferation and hence cannot result in re-pigmentation as a monotherapy. There is a need for tissue-based JAK and cytokine-based studies with post-treatment expression data to validate the role of this class of drugs in vitiligo. There is as yet no data to suggest that selective JAK inhibitors are superior to pan JAK inhibitors for vitiligo. JAK inhibitors are useful in active disease and effectively modulate the cytokine mediated autoimmune dammage and makes them singularly superior to oral glucocorticosteroids.