An Open-Label Pilot Study to Evaluate the Efficacy of Tofacitinib in Moderate to Severe Patch-Type Alopecia Areata, Totalis, and Universalis

Current Landscape of Chronic Inflammatory Dermatoses: Where We Are and Where We Are Heading

Chronic inflammatory dermatoses represent a heterogeneous group of skin disorders that are often characterized by persistent and relapsing inflammation, with complex underlying pathomechanisms [...].

Predictors and Management of Inadequate Response to JAK Inhibitors in Alopecia Areata

Alopecia areata is a common autoimmune disorder characterized by non-scarring hair loss on the scalp or other hair-bearing surface. In recent years, Janus kinase (JAK) inhibitors have shown promise in the treatment of alopecia areata by disrupting the signaling pathways involved in immune-mediated hair follicle damage. However, some patients with alopecia areata exhibit insufficient responses to JAK inhibitors. This review aims to explore the predictive factors for poor responses to JAK inhibitors in patients with alopecia areata and to discuss alternative treatment strategies in such cases. Patients with a longer duration of the current episode and higher baseline severity are at an increased risk of inadequate JAK inhibitor responses. Oral administration rather than topical application, and extended treatment durations, correlate with a favorable response. Notably, the poor response to JAK inhibitors in alopecia areata may be related to the amount and functional depletion of regulatory T cells resulting from an augmented T helper-2-type immune response. For patients with poor responses to JAK inhibitors, treatment adjustments may include increasing the dosage, extending the treatment duration, combination therapies, or switching to alternative JAK inhibitors. For patients with atopic comorbidities or psychological problems, it is important to select corresponding treatment options to optimize patient outcomes. Further research is needed to establish more reliable predictors and improve overall patient care.

Comparison of efficacy and safety of tofacitinib and azathioprine in patients with alopecia areata and variants: a double-blind, randomized controlled trial

BACKGROUND

Alopecia areata (AA) is an autoimmune pathology manifested by loss of hair.

OBJECTIVE

To evaluate and compare the efficacy and safety of tofacitinib and azathioprine in patients with AA and variants.

METHODS

In this double-blind randomized controlled trail (RCT) carried out at the Department of Dermatology, Medical Teaching Institute-Lady Reading Hospital (MTI-LRH), Peshawar, Pakistan, patients aged ≥ 12 years diagnosed with AA, alopecia totalis (AT) or alopecia universalis (AU) with minimum 50% scalp hair loss for a period ≥ 06 years were included. Patients were randomly assigned to receive oral tofacitinib 5 mg twice daily (Group I) or oral azathioprine 2 mg/kg body weight once daily (Group II). The primary endpoint was Severity of Alopecia Tool (SALT) score, evaluated at baseline and 06 months follow-up. Safety was consistently assessed during the study.

RESULTS

A total of 104 patients underwent random allocation into either the tofacitinib group (n = 52) or the azathioprine group (n = 52). The mean (SD) age of patients was 20.23 (7.14) years and 22.26 (8.07) years, while the mean (SD) disease duration was 6.59 (4.01) years and 7.98 (4.40) years in in Group I and II, respectively. Overall, 40 (38.5%) patients were adolescents while 70 (67.3%) were male. 52 (50%) had AA, 37 (35.5%) had AT and 15 (14.5%) had AU. Mean baseline SALT score in tofacitinib group was 91.02 ± 10.21 and azathioprine group was 91.02 ± 10.63, which at 06 months follow-up improved to 14.1 ± 24.6 and 63.9 ± 33.9, respectively (difference, 11.5 points; 95% confidence interval, 38.3-61.3, p < 0.0001). Overall, no major adverse effects and no difference among the minor adverse effects in the two groups (04 adverse events for tofacitinib group and 08 for azathioprine group: p = 0.23) was observed.

CONCLUSIONS

Efficacy of tofacitinib was significantly higher than azathioprine, whilst both drugs were well-tolerated in patients with AA and variants.

Real-world effectiveness and safety of tofacitinib for alopecia areata: A retrospective cohort study of 202 patients

BACKGROUND

Alopecia areata (AA) is an autoimmune hair loss disorder characterised by collapse of hair follicle immune privilege and mediated by autoreactive CD8+ T lymphocytes and natural killer cells. Treatment is often unsatisfactory. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is implicated in the pathogenesis of AA and Janus Kinase inhibitor (JAKi) medications are promising emerging treatments for AA.

OBJECTIVES

We evaluated the safety and effectiveness of tofacitinib in a real-world setting over 18 months of treatment.

METHODS

A retrospective cohort study of all patients with scalp AA commenced on tofacitinib between 1 November 2016 and 31 May 2019. The primary endpoint was the percent change in Severity of Alopecia Tool (SALT) score at 18 months.

RESULTS

Two hundred and two patients were included. After 18 months of treatment, 55.9%, 42.6% and 29.2% achieved 50%, 75% and 90% reductions in their SALT scores respectively. Increased duration of AA was a negative predictor of hair regrowth. Males and patients with baseline SALT ≥90 were slower to respond to treatment in the first 12 months. One hundred and twenty-four patients and 168 patients received concomitant systemic corticosteroids or low-dose oral minoxidil during tofacitinib therapy respectively. There were no serious adverse events.

CONCLUSION

Tofacitinib was a safe and effective treatment for patients with moderate-to-severe AA. Further randomised controlled studies are needed to establish the optimal treatment regimen.

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.

Precision Dermatology: A Review of Molecular Biomarkers and Personalized Therapies

The evolution of personalized medicine in dermatology signifies a transformative shift towards individualized treatments, driven by the integration of biomarkers. These molecular indicators serve beyond diagnostics, offering insights into disease staging, prognosis, and therapeutic monitoring. Specific criteria guide biomarker selection, ensuring attributes like specificity, sensitivity, cost feasibility, stability, rapid detection, and reproducibility. This literature review, based on data from PubMed, SCOPUS, and Web of Science, explores biomarkers in Hidradenitis Suppurativa (HS), Psoriasis, Atopic Dermatitis (AD), Alopecia Areata (AA), Vitiligo, and Chronic Spontaneous Urticaria (CSU). In HS, TNF-α, IL-1β, and MMPs serve as biomarkers, influencing targeted therapies like adalimumab and anakinra. Psoriasis involves biomarkers such as TNF-α, IL-23, and HLA genes, shaping treatments like IL23 and IL17 inhibitors. AD biomarkers include ECP, IL-4, IL-13, guiding therapies like dupilumab and tralokinumab. For AA, lipocalin-2, cytokines, and genetic polymorphisms inform JAK inhibitors' use. Vitiligo biomarkers range from cytokines to genetic markers like TYR, TYRP1, guiding treatments like JAK inhibitors. CSU biomarkers encompass IgE, cytokines, and autologous serum tests, influencing therapies like omalizumab and cyclosporine. Comparing conditions, common proinflammatory markers reveal limited specificity. While some biomarkers aid diagnosis and standard treatments, others hold more scientific than clinical value. Precision medicine, driven by biomarkers, has shown success in skin malignancies. Future directions involve AI-powered algorithms, nanotechnology, and multi-omics integration for personalized dermatological care.

Effectiveness of oral tofacitinib treatment on patients with moderate-to-severe alopecia areata in Iran

INTRODUCTION

Alopecia areata is an inflammatory hair loss and a common autoimmune disease. Conducting treatment studies on alopecia areata is difficult due to unpredictable periods and even spontaneous recovery from the disease. In this study, the effectiveness of tofacitinib in treating alopecia areata was investigated.

MATERIALS AND METHODS

The severity of the disease was evaluated using the Alopecia Severity Tool (SALT), and based on the medical history and patient's documents and photos, the score before and after the treatment was obtained. The patients were prescribed tofacitinib tablets at a dose of 5 mg twice a day for at least 6 months and were followed for a minimum of 18 months.

RESULTS

No side effect was observed in 97.9% of the patients. After 6 months, except for three patients who did not need any maintenance dose, others needed an average daily intake of 7 mg of tofacitinib. After 18 months, the hair loss decreased by 6.45 times compared to the beginning and by 0.5 times compared to the end of 6 months (p < 0.05). In addition, it was found that body hair loss decreased 4 times compared to the beginning and 0.6 times compared to the end of 6 months (p < 0.05). The reduction of nail involvement after 18 months and 6 months was 1.2 times and 0.6, respectively, (p < 0.05).

CONCLUSION

Treatment of alopecia areata with tofacitinib is recommended due to its effectiveness in reducing hair loss on the head, body, and nail involvement with few reversible side effects.

Alopecia areata: What's new in the diagnosis and treatment with JAK inhibitors?

Alopecia areata (AA) affects individuals of all ages and is intractable in severe relapsing cases. Dermatologists and other healthcare providers should consider AA in the medical context and prioritize treatment. Several randomized controlled clinical studies on Janus kinase (JAK) inhibitors with different specificities for the treatment of AA are ongoing. These studies have encouraged us to appreciate the importance of a definitive diagnosis and accurate evaluation of AA before and during treatment. Following our previous review article in 2017, here we provide the second part of this two-review series on the recent progress in the multidisciplinary approaches to AA from more than 1800 articles published between July 2016 and December 2022. This review focuses on the evaluation, diagnosis, and treatment of AA. We also provide the latest information on the safety and efficacy of JAK inhibitors for the treatment of AA and describe their mechanisms of action.

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.

Effectiveness and Predictive Factors of Response to Tofacitinib Therapy in 125 Patients with Alopecia Areata: A Single-centre Real-world Retrospective Study

Alopecia areata is an autoimmune disorder that greatly impacts patients' quality of life, and its management remains challenging. Tofacitinib is the first Janus kinase inhibitor to be approved for clinical use and is the most extensively studied. Several studies have demonstrated the clinical effectiveness of oral tofacitinib in treating patients with alopecia areata. However, despite being widely used in clinical practice, no prospective randomized controlled trials have been implemented and its indication criteria have not been thoroughly established. Moreover, little is known about the factors associated with response to therapy under real-world conditions. The aims of this retrospective cohort study of patients with alopecia areata treated with tofacitinib for 3 months were to assess the effectiveness of tofacitinib and to identify predictive factors of response to it. Primary outcome was the change in disease severity, as evaluated by Severity of Alopecia Tool (SALT) grade. A total of 125 patients with alopecia areata were included, the incidence of effectiveness was 83.2%, and 16.0% of patients achieved a result of complete remission. Total duration of alopecia areata and previous hair regrowth were independent predictors of response. Combined therapy was associated with relapse after discontinuation. No severe adverse event was observed. This study suggests that tofacitinib provides an effective treatment option for patients with alopecia areata, and that earlier intervention in the treatment of severe alopecia areata with tofacitinib may lead to better outcomes.

Treatments for Moderate-to-Severe Alopecia Areata: A Systematic Narrative Review

Treatments for alopecia areata (AA) have traditionally been prescribed off-label, and there has been no universal agreement on how to best manage the condition. Baricitinib is the first oral selective Janus kinase (JAK) inhibitor approved for the treatment of adults with severe AA. As a better understanding of the evidence supporting the management of AA in clinical practice is needed, we conducted a systematic literature review and subsequent narrative review to describe available evidence pertaining to the efficacy and tolerability of treatments currently recommended for adults with moderate-to-severe forms of AA. From 2557 identified records, a total of 53 records were retained for data extraction: 9 reported data from 7 randomized controlled trials (RCTs) versus placebo, and 44 reported data from unique RCTs with no placebo arm, non-randomized trials, or observational studies. Across drug classes, data were reported heterogeneously, with little consistency of data collection or clinical endpoints used. The most robust evidence was for the JAK inhibitor class, in particular the JAK1/JAK2 inhibitor baricitinib. Five RCTs (three for baricitinib) demonstrated a consistent benefit of JAK inhibitor therapy over placebo across various clinical outcomes in adult patients with at least 50% scalp hair loss. Overall, hair regrowth varied widely for the other drug classes and was generally low for patients with moderate-to-severe AA. Relapses were commonly observed during treatment and upon discontinuation. Adverse effects were generally consistent with the known safety profile of each intervention. The heterogeneity observed prevented the conduct of a network meta-analysis or an indirect comparison of different treatments. We found that the current management of patients with moderate-to-severe AA often relies on the use of treatments that have not been well evaluated in clinical trials. The most robust evidence identified supported the use of baricitinib, and other oral JAK inhibitors, in patients with severe AA.

Resident cutaneous memory T cells: a clinical review of their role in chronic inflammatory dermatoses and potential as therapeutic targets

Resident memory T cells (T-RMs) remain in epithelial barrier tissues after antigen exposure and the initial effector phase. These T-RMs provide effective antimicrobial and anticancer immunity; however, pathogenic T-RMs have been shown to mediate various chronic inflammatory disorders in a variety of tissue types. In the skin, T-RMs are referred to as resident cutaneous memory T cells (cT-RMs). Understanding the mechanisms leading to the development and establishment of these cT-RMs populations may allow for targeted treatments that provide durable responses in chronic immune-mediated skin diseases, even after cessation. In this review, we summarize the evidence on cT-RMs as drivers of chronic inflammatory dermatoses, including psoriasis, vitiligo, atopic dermatitis, cutaneous lupus erythematosus and alopecia areata, among others. Data from in vitro, animal model and ex vivo human studies are presented, with a focus on the potential for cT-RMs to trigger acute disease flares, as well as recurrent disease, by establishing an immune 'memory' in the skin. Furthermore, the available data on the potential for existing and novel treatments to affect the development or survival of cT-RMs in the skin are synthesized. The data suggest a dynamic and rapidly growing area in the field of dermatology; however, we also discuss areas in need of greater research to allow for optimal treatment selection for long-term disease control.

Drug Survival and Long-term Outcome of Tofacitinib in Patients with Alopecia Areata: A Retrospective Study

Several non-randomized clinical trials and retrospective studies have demonstrated encouraging efficacy and well-tolerated safety of tofacitinib in the treatment of alopecia areata. However, there are scarce data on a large cohort of patients with alopecia areata in long-term real-world practice. This single-centre, retrospective, observational cohort study included 126 patients with alopecia areata treated with tofacitinib between February 2021 and December 2022. The aims of this study are to evaluate drug survival, effectiveness and safety of tofacitinib for treatment of alopecia areata, and to identify potential factors influencing long-term outcomes. Median duration of treatment was 23.00 (interquartile range (IQR) 15.00, 47.25) weeks. Median all-cause survival time of 126 patients treated with tofacitinib was 44 weeks (95% confidence interval (95% CI) 36.3, 51.7), and the all-cause drug retention rate at 12 weeks, 24 weeks and 48 weeks were 90.0%, 66.4% and 42.3%, respectively. The most common reason for discontinuation was complete remission/satisfaction. A total of 80 patients treated with tofacitinib for over 6 months were included in the efficacy analysis, the overall complete response rate at 24 weeks was 33.8% (27/80). No life-threatening serious adverse events occurred. Sex is an independent risk factor in predicting patient outcomes. This real-world study confirmed the high effectiveness and acceptable safety profile of tofacitinib in alopecia areata, with a satisfactory drug survival rate, and provides supporting data for the clinical application of tofacitinib in Chinese patients with alopecia areata.

Janus kinase inhibitors for alopecia areata: A narrative review

The Janus kinase (JAK) and Signal Transducer and Activator of Transcription (STAT) pathway has been identified as a key player in the pathophysiology of alopecia areata and a potential target for therapy. Here, we give a narrative review of what is known about Janus kinase inhibitors in alopecia areata. Several clinical trials as well as smaller studies have demonstrated hair regrowth and remission with oral Janus kinase inhibitors therapy, even in patients who failed conventional treatment. Baricitinib is the only US FDA-approved treatment for alopecia areata but data for other oral Janus kinase inhibitors such as tofacitinib, ruxolitinib and ritlecitinib are also promising. Fewer clinical trials have investigated topical Janus kinase inhibitors for alopecia areata, with many of them terminated early due to unfavourable results. Overall, Janus kinase inhibitors are an efficacious addition to the therapeutic arsenal for treatment-refractory alopecia areata. Further work is needed to examine the effects of long-term usage of Janus kinase inhibitors, the efficacy of topical Janus kinase inhibitors, as well as to identify biomarkers that could predict differential therapeutic responses to the various Janus kinase inhibitors.

Alopecia Areata: Current Treatments and New Directions

Alopecia areata is an autoimmune hair loss disease that is non-scarring and is characterized by chronic inflammation at the hair follicle level. Clinically, patients' presentation varies from patchy, circumscribed scalp involvement to total body and scalp hair loss. Current management is guided by the degree of scalp and body involvement, with topical and intralesional steroid injections as primarily first-line for mild cases and broad immunosuppressants as the mainstay for more severe cases. Until recently, the limited number of blinded, randomized, placebo-controlled clinical trials for this disease had made establishing an evidence-based treatment paradigm challenging. However, growing insights into the pathogenesis of alopecia areata through blood and tissue analysis of human lesions have identified several promising targets for therapy. T-helper (Th) 1/interferon skewing has traditionally been described as the driver of disease; however, recent investigations suggest activation of additional immune mediators, including the Th2 pathway, interleukin (IL)-9, IL-23, and IL-32, as contributors to alopecia areata pathogenesis. The landscape of alopecia areata treatment has the potential to be transformed, as several novel targeted drugs are currently undergoing clinical trials. Given the recent US FDA approval of baricitinib and ritlecitinib, Janus kinase (JAK) inhibitors are a promising drug class for treating severe alopecia areata cases. This article will review the efficacy, safety, and tolerability of current treatments for alopecia areata, and will provide an overview of the emerging therapies that are leading the revolution in the management of this challenging disease.

Diagnosis and Management of Alopecia Areata: A Saudi Expert Consensus Statement (2023)

Alopecia areata (AA) is a complex autoimmune disease manifesting as a chronic inflammatory disease characterized by non-scarring patches of hair loss over the face, scalp, and body. Several treatments have been proposed for AA, but none are curative nor achieve a state of remission. The present consensus statement aims to present the evidence- and experience-based recommendations on the diagnosis and management of AA in Saudi Arabia. The Ministry of Health in Saudi Arabia has opted to initiate a meeting of a multidisciplinary group to discuss and concede on this topic. Eight dermatology experts and clinical pharmacists convened in eight consensus meetings. All content presented in this document was agreed upon by this working group, including diagnosis and severity assessment, prognostic indicators, and therapeutic options for AA. Special consideration was given to special patient populations including pediatric patients and patients with less frequent presentations of AA. Updates of the current recommendations will take place as new evidence evolves in the treatment of AA.

Tofacitinib in the Management of Alopecia Universalis

Alopecia universalis (AU) is a rare form of hair loss characterized by the complete absence of hair on the scalp and body. It is an advanced form of alopecia areata. There is currently no definitive treatment for this condition, and management options are limited. This case report describes the successful treatment of a 37-year-old female patient with AU using oral tofacitinib 5 mg BID, an oral Janus kinase inhibitor. The patient experienced clinically significant hair regrowth on the scalp and eyebrows after 6 months of treatment with tofacitinib, along with the concurrent use of oral mini-pulse betamethasone, topical minoxidil 5%, and clobetasol lotion. This case highlights the potential efficacy of tofacitinib as a promising therapeutic option for AU, without notable safety concerns. Moreover, it is also well tolerated in this patient.

Preparation and evaluation of dissolving tofacitinib microneedles for effective management of rheumatoid arthritis

Dissolving microneedles have become a focal point in transdermal drug delivery. They have the advantages of painless, rapid drug delivery and high drug utilization. The purpose of this study was to evaluate the efficacy of Tofacitinib citrate microneedles in arthritis treatment, assess the dose-effect relationship, and determine the cumulative penetration during percutaneous injection. In this study, block copolymer was utilized to prepare the dissolving microneedles. The microneedles were characterized through skin permeation tests, dissolution tests, treatment effect evaluations, and Western blot experiments. In vivo dissolution experiments revealed that the soluble microneedles completely dissolved within 2.5 min, while in vitro skin permeation experiments demonstrated the highest unit area of skin permeation of the microneedles reached 2118.13 mg/cm2. The inhibition of Tofacitinib microneedle on joint swelling in rats with Rheumatoid arthritis was better than Ketoprofen and close to that of oral Tofacitinib. Western-blot experiment comfirmed the Tofacitinib microneedle's inhibitory effect on the JAK-STAT3 pathway in rats with Rheumatoid arthritis. In conclusion, Tofacitinib microneedles effectively inhibited arthritis in rats, demonstrating potential for Rheumatoid arthritis treatment.

Functional interrogation of lymphocyte subsets in alopecia areata using single-cell RNA sequencing

Alopecia areata (AA) is among the most prevalent autoimmune diseases, but the development of innovative therapeutic strategies has lagged due to an incomplete understanding of the immunological underpinnings of disease. Here, we performed single-cell RNA sequencing (scRNAseq) of skin-infiltrating immune cells from the graft-induced C3H/HeJ mouse model of AA, coupled with antibody-based depletion to interrogate the functional role of specific cell types in AA in vivo. Since AA is predominantly T cell-mediated, we focused on dissecting lymphocyte function in AA. Both our scRNAseq and functional studies established CD8+ T cells as the primary disease-driving cell type in AA. Only the depletion of CD8+ T cells, but not CD4+ T cells, NK, B, or γδ T cells, was sufficient to prevent and reverse AA. Selective depletion of regulatory T cells (Treg) showed that Treg are protective against AA in C3H/HeJ mice, suggesting that failure of Treg-mediated immunosuppression is not a major disease mechanism in AA. Focused analyses of CD8+ T cells revealed five subsets, whose heterogeneity is defined by an "effectorness gradient" of interrelated transcriptional states that culminate in increased effector function and tissue residency. scRNAseq of human AA skin showed that CD8+ T cells in human AA follow a similar trajectory, underscoring that shared mechanisms drive disease in both murine and human AA. Our study represents a comprehensive, systematic interrogation of lymphocyte heterogeneity in AA and uncovers a novel framework for AA-associated CD8+ T cells with implications for the design of future therapeutics.

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

Alopecia areata (AA) is an immune-mediated condition, clinically manifesting as non-cicatricial patches of alopecia. It is often a self-limiting condition; however, regrowth of hair can take a long period of time, resulting in significant psychological comorbidity. With the recent advances in pathomechanisms of AA, the therapeutic approach to the condition has become more specific, and targeted therapy with small molecules is probably the ideal intervention. Many therapies exist for AA, but none of the systemic agents were approved, until recently, when baricitinib (Janus kinase (JAK1 and JAK2 inhibitor) gained FDA approval for the treatment of adult patients with severe AA. JAK inhibitors (JAKibs) target the γc cytokine and interferon-gamma (IFN-γ) signaling pathway, which is critical to the immunopathogenesis of AA and thus can reverse the hair loss in AA. Although JAKibs are emerging as a promising treatment modality for AA, the ideal JAKib is not yet settled, as there is scant data on H-2-H (head-to-head) comparisons of JAK inhibitors in AA. Moreover, the response achieved with JAKibs is not sustained after treatment discontinuation, with many studies showing a high recurrence rate with tofacitinib and ruxolitinib post-treatment. Also, recent studies have hypothesized that JAK2, with its ubiquitous expression, can cause adverse effects, unlike JAK1, which is associated with multiple major cytokine receptor families and JAK3, which is exclusively associated with the γc cytokine receptor. Thus, JAK3ibs may be associated with a better side effect profile and, in conjunction with their specificity, may replace other JAKibs as the treatment of choice for AA. We herein discuss the role of the JAK/STAT (signal transducer and activator of transcription) pathway in AA, the intricacies of various JAKibs in the management of AA, and emphasize the need for studies on tissue JAK and cytokine expression before arriving at the ideal JAKibs for AA.

Functional heterogeneity of human skin-resident memory T cells in health and disease

The human skin is populated by a diverse pool of memory T cells, which can act rapidly in response to pathogens and cancer antigens. Tissue-resident memory T cells (TRM ) have been implicated in range of allergic, autoimmune and inflammatory skin diseases. Clonal expansion of cells with TRM properties is also known to contribute to cutaneous T-cell lymphoma. Here, we review the heterogeneous phenotypes, transcriptional programs, and effector functions of skin TRM . We summarize recent studies on TRM formation, longevity, plasticity, and retrograde migration and contextualize the findings to skin TRM and their role in maintaining skin homeostasis and altered functions in skin disease.

Clinical and Genetic Aspects of Alopecia Areata: A Cutting Edge Review

Alopecia areata (AA) is a chronic, non-scarring, immune-mediated skin disease that affects approximately 0.5-2% of the global population. The etiology of AA is complex and involves genetic and environmental factors, with significant advancements in genetic research occurring in recent years. In addition to well-known genes such as PTPN22, CTLA4, and IL2, which have been widely supported as being associated with AA, an increasing number of specific gene-related loci have been discovered through advances in genetic research. For instance, gene analysis of microRNAs can reveal the critical role of miRNAs in regulating gene expression, aiding in the understanding of cellular and organismal functional regulatory mechanisms. Furthermore, numerous studies have confirmed the existence of correlations between AA and other immune-related diseases. Examples include hyperthyroidism and rheumatoid arthritis. By understanding the interrelationships between AA and other immune diseases, we can further comprehend potential shared genetic foundations or pathogenic mechanisms among different diseases. Genetic research plays a crucial role in unraveling the pathogenesis of AA, as the identification of genetic variations associated with AA can assist in formulating more effective and targeted treatment strategies.

Hair Growth Effect of DN106212 in C57BL/6 Mouse and Its Network Pharmacological Mechanism of Action

Centipeda minima (CMX) has been widely investigated using network pharmacology and clinical studies for its effects on hair growth via the JAK/STAT signaling pathway. Human hair follicle papilla cells exhibit hair regrowth through the expression of Wnt signaling-related proteins. However, the mechanism of action of CMX in animals has not been elucidated fully. This study examined the effect of induced hair loss and its side-effects on the skin, and observed the mechanism of action of an alcoholic extract of CMX (DN106212) on C57BL/6 mice. Our results showed that DN106212 was more effective in promoting hair growth than dimethyl sulfoxide in the negative control and tofacitinib (TF) in the positive control when mice were treated with DN106212 for 16 days. We confirmed that DN106212 promotes the formation of mature hair follicles through hematoxylin and eosin staining. We also found that the expression of vascular endothelial growth factor (Vegfa), insulin-like growth factor 1 (Igf1), and transforming growth factor beta 1 (Tgfb1) is related to hair growth using PCR. DN106212-treated mice had significantly higher expression of Vegfa and Igf1 than TF-treated ones, and inhibiting the expression of Tgfb1 had similar effects as TF treatment. In conclusion, we propose that DN106212 increases the expression of hair growth factors, promotes the development of hair follicles, and promotes hair growth. Although additional experiments are needed, DN106212 may serve as an experimental basis for research on natural hair growth-promoting agents.

The evaluation of JAK inhibitors on effect and safety in alopecia areata: a systematic review and meta-analysis of 2018 patients

Background

JAK inhibitors treat various autoimmune diseases, but an updated systematic review in treating alopecia areata is currently lacking.

Objective

Evaluate the specific efficacy and safety of JAK inhibitors in alopecia areata by systematic review and meta-analysis.

Methods

Eligible studies in PubMed, Embase, Web of Science, and Clinical Trials up to May 30, 2022, were searched. We enrolled in randomized controlled trials and observational studies of applying JAK inhibitors in alopecia areata.

Results

6 randomized controlled trials with 1455 patients exhibited SALT₅₀ (odd ratio [OR], 5.08; 95% confidence interval [CI], 3.49-7.38), SALT₉₀ (OR, 7.40; 95% CI, 4.34-12.67) and change in SALT score (weighted mean difference [WSD], 5.55; 95% CI, 2.60-8.50) compared to the placebo. The proportion of 26 observational studies with 563 patients of SALT₅ was 0.71(95% CI, 0.65-0.78), SALT₅₀ was 0.54(95% CI 0.46-0.63), SALT₉₀ was 0.33(95% CI, 0.24-0.42), and SALT score (WSD, -2.18; 95% CI, -3.12 to -1.23) compared with baseline. Any adverse effects occurred in 921 of 1508 patients; a total of 30 patients discontinued the trial owing to adverse reactions.

Limitations

Few randomized controlled trials met the inclusion criteria and insufficiency of eligible data.

Conclusion

JAK inhibitors are effective in alopecia areata, although associated with an increased risk.

Baricitinib for the Treatment of Alopecia Areata

Alopecia areata (AA) is a relapsing, chronic, immune-mediated disease characterized by nonscarring, inflammatory hair loss that can affect any hair-bearing site. AA clinical presentation is heterogeneous. Its pathogenesis involves immune and genetic factors and several pro-inflammatory cytokines involved in AA pathogenesis, including interleukin-15 and interferon-γ, as well as Th2 cytokines, such as IL-4/IL-13, that signal through Janus kinase (JAK) pathway. AA treatment aims to stop its progression and reverse hair loss, and JAK inhibition has been shown to stop hair loss and reverse alopecia and has exhibited promising results in treating AA in clinical trials. Baricitinib, an oral, reversible, selective JAK1/JAK2 inhibitor, was shown to be superior to placebo on hair growth after 36 weeks of treatment in adults with severe AA in a phase 2 trial and recently in two phase 3 trials (BRAVE-AA1 and BRAVE-AA2). In both studies, the most common adverse events were upper respiratory tract infections, urinary tract infection, acne, headache, and elevated creatine kinase levels. On the basis of these trial results, baricitinib was recently approved by the European Medicines Agency (EMA) and US Food and Drug Administration (FDA) for the treatment of adults with severe AA. Nevertheless, longer trials are needed to determine the long-term efficacy and safety of baricitinib in AA. Current trials are ongoing and are planned to remain randomized and blinded for up to 200 weeks.

Safety of Janus Kinase inhibitors in Patients with Alopecia Areata: A Systematic Review

BACKGROUND AND OBJECTIVES

Janus kinase (JAK) inhibitors are emerging as a therapeutic option for alopecia areata. The risk of potential adverse events is currently debated. In particular, several safety data for JAK inhibitors are extrapolated from a single study in elderly patients with rheumatoid arthritis treated with tofacitinib or adalimumab/etanercept as a comparator. The population of patients with alopecia areata is clinically and immunologically different from persons with rheumatoid arthritis and tumor necrosis factor (TNF) inhibitors are not effective in these patients. The objective of this systematic review was to analyze available data on the safety of various JAK inhibitors in patients with alopecia areata.

METHODS

The systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A literature review was performed by searching PubMed, Scopus and EBSCO databases with the last search on March 13, 2023.

RESULTS

In total, 36 studies were included. The frequency and odds ratio (OR) for most common adverse events versus placebo were: for baricitinib hypercholesterolemia (18.2% vs 10.5%, OR = 1.9) and headache (6.1% vs 5.1%, OR = 1.2), for brepocitinib elevated creatinine level (27.7% vs 4.3%, OR = 8.6) and acne (10.6% vs 4.3%, OR = 2.7), for ritlecitinib acne (10.4% vs 4.3%, OR = 2.6) and headache (12.5% vs 10.6%, OR = 1.2) and for deuruxolitinib headache (21.4% vs 9.1%, OR = 2.7) and acne (13.6% vs 4.5%, OR = 3.3). The respective numbers for upper respiratory infections were: baricitinib (7.3% vs 7.0%, OR = 1.0) and brepocitinib (23.4% vs 10.6%, OR = 2.6); for nasopharyngitis: ritlecitinib (12.5% vs 12.8%, OR = 1.0) and deuruxolitinib (14.6% vs 2.3%, OR = 7.3).

CONCLUSIONS

The most common side effects of JAK inhibitors in patients with alopecia areata were headache and acne. The OR for upper respiratory tract infections varied from over 7-fold increased to comparable to placebo. The risk of serious adverse events was not increased.

Recent Advances in Understanding of the Etiopathogenesis, Diagnosis, and Management of Hair Loss Diseases

Hair-loss diseases comprise heterogenous conditions with respective pathophysiology and clinicopathological characteristics. Major breakthroughs in hair follicle biology and immunology have led to the elucidation of etiopathogenesis of non-scarring alopecia (e.g., alopecia areata, AA) and cicatricial alopecia (e.g., lichen planopilaris, LPP). High-throughput genetic analyses revealed molecular mechanism underlying the disease susceptibility of hair loss conditions, such as androgenetic alopecia (AGA) and female pattern hair loss (FPHL). Hair loss attracted public interest during the COVID-19 pandemic. The knowledge of hair loss diseases is robustly expanding and thus requires timely updates. In this review, the diagnostic and measurement methodologies applied to hair loss diseases are updated. Of note, novel criteria and classification/scoring systems published in the last decade are reviewed, highlighting their advantages over conventional ones. Emerging diagnostic techniques are itemized with clinical pearls enabling efficient utilization. Recent advances in understanding the etiopathogenesis and management for representative hair diseases, namely AGA, FPHL, AA, and major primary cicatricial alopecia, including LPP, are comprehensively summarized, focusing on causative factors, genetic predisposition, new disease entity, and novel therapeutic options. Lastly, the association between COVID-19 and hair loss is discussed to delineate telogen effluvium as the predominating pathomechanism accounting for this sequela.

Recent advances in the genetics of alopecia areata

Alopecia areata (AA) is a common autoimmune-mediated hair loss disorder in humans with an estimated lifetime risk of approximately 2 %. Episodes of hair loss usually begin with isolated hairless patches that may progress to complete hair loss over the entire body. A familial occurrence of AA is well established, with recurrence risks of about 6-8 % in first-degree relatives. AA is a multifactorial disorder involving both environmental and genetic risk factors. Previous research has identified 14 susceptibility loci, most of which implicate genes involved in the immune response. The following review presents a summary of the latest findings from genome-wide association, sequencing and gene expression studies of AA, as well as their contribution to the recent therapeutic developments.

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

INTRODUCTION

Numerous cutaneous dermatoses mediated by cytokines depend on the JAK STAT pathway for intracellular signaling. JAK inhibitors form a useful therapeutic approach in treating these conditions. The literature on effectiveness of JAK inhibitors in treatment of alopecia areata, vitiligo, atopic dermatitis, psoriasis and several other inflammatory and autoimmune diseases is growing, although very few conditions have sufficiently well performed studies to their credit and barring a few indications, their use in rest remains empirical as yet.

AREAS COVERED

A search of the PubMed database was made using the keywords Janus kinase inhibitors OR JAK inhibitors AND dermatology with the time duration limited to the last 5 years. Here, we review the JAK STAT pathway and the various conditions in which JAK inhibitors are currently used in dermatology and other conditions their use is being explored in.

EXPERT OPINION

The pathology of a large number of dermatological disorders is mediated via inflammatory cytokines which signal via the JAK STAT pathway. JAKinibs have shown great promise in treating cutaneous disorders refractory to conventional therapy. Their current clinical use in dermatology is based on robust evidence (for some), and anecdotal evidence for most other dermatoses.

A phase 2a randomized vehicle-controlled multi-center study of the safety and efficacy of delgocitinib in subjects with moderate-to-severe alopecia areata

Alopecia areata/AA is an autoimmune cause of nonscarring hair loss. The pathogenesis of AA involves many immune axes, including Th1/Th2 pathways. Delgocitinib is a pan-Janus kinase/JAK inhibitor that broadly blocks pro-inflammatory cytokines and has been effective in other inflammatory skin conditions. Recent human studies/reports have shown that use of some systemic JAK inhibitors led to hair regrowth, suggesting this medication class as a potential therapy for AA. However, topical treatment is desirable due to potential systemic side effects. To assess the efficacy and safety of topical delgocitinib in AA, we conducted a double-blind, randomized, vehicle-controlled clinical trial in 31 moderate-to-severe AA patients that were randomized 2:1 to receive delgocitinib ointment 30 mg/g (n = 20) or ointment vehicle (n = 11) for 12 weeks. The primary endpoint was change in severity of Alopecia Tool/SALT score from baseline to week 12. The secondary endpoint included safety profile by reported adverse events. Twenty-three subjects completed the trial, with eight discontinuing mostly due to voluntary withdrawal. Ten patients receiving delgocitinib ointment and three patients receiving vehicle showed SALT score improvements after 12 weeks, but the mean percent SALT improvement at week 12 compared to baseline between the two arms was not significant (p = 0.92). Our study suggests that delgocitinib ointment is not effective in moderate-to-severe AA, likely due to its inability to penetrate sufficiently deeply into the dermis of the scalp, but larger studies are necessary to assess whether a different formulation of topical JAK inhibitors may be suitable to treat mild or more localized forms of AA.

Janus Kinase Inhibitors in the Treatment of Alopecia Areata

Alopecia areata is a disease of autoimmune origin which causes non scarring hair loss. The extent of alopecia varies from a small patch to complete scalp and body hair loss, which can have huge psychosocial impact for those affected. Treatment modalities which have been used so far included nonspecific immunosuppressive medications, such as corticosteroids, cyclosporine, and methotrexate, or topical immunomodulators, such as diphencyprone, dithranol, and squaric acid dibutylester. The recognition of the importance of Janus kinase pathway in alopecia areata pathogenesis enabled more specific approaches in treatment. Positive outcomes of Janus kinase inhibitors in several trials granted approval for baricitinib which became the first on-label treatment for alopecia areata. The aim of this review is to summarize the role, efficacy and safety of several Janus kinase inhibitors in alopecia areata.

Effectiveness and safety of baricitinib in patients with alopecia areata: a systematic review and Meta-analysis of randomized controlled trials

BACKGROUND

Since there is now no medication available that has been approved by the US Food and Drug Administration, alopecia areata (AA) is an autoimmune condition that has a detrimental impact on individuals. Recent clinical trials using baricitinib demonstrated that it may be effective in treating AA. This meta-analysis was done to evaluate the effectiveness and safety of baricitinib in comparison to placebo.

METHODS

Author looked through Scopus, Web of Science, Cochrane Library, PubMed, for all published, randomized, clinical trials.

RESULTS

This meta-analysis included 1282 participants from two citations (reporting three stand-alone studies). In term of SALT score, baricitinib significantly outperformed placebo; MD = -34.07, 95% CI [-37.90, -30.23], p < .00001. Additionally, the proportion of patients in the baricitinib group that attained SALT ≤ 20 was significantly higher than in the placebo group; RR = 6.41, 95% CI [4.57, 8.98], p < .00001. The results of the safety analysis revealed no significant differences between the baricitinib and placebo groups for any of the outcomes with the exception of acne, which was significantly higher in the placebo group when compared to the baricitinib group (RR= 4.79, 95% CI [2.38, 9.66], p .0001).

CONCLUSION

When compared to placebo, baricitinib is an effective and well-tolerated medication for the treatment of AA.

Comparative Efficacy and Safety of Janus Kinase Inhibitors Used in Alopecia Areata: A Systematic Review and Meta-analysis

The aim of this study was to compare the efficacy and safety of treatment with Janus kinase inhibitors for alopecia areata, measured by change in Severity of Alopecia Tool (SALT) score. A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines was performed using Medline, EMBASE and Cochrane library. All studies investigating the efficacy of treatments for alopecia areata were included. Primary outcomes were the proportion of patients with alopecia areata achieving 30%, 50%, 75%, 90% and 100% improvement in SALT score after treatment with a Janus kinase inhibitor. A meta-analysis was performed including all randomized controlled trials investigating Janus kinase inhibitors. A total of 37 studies matched the inclusion criteria and were included. Meta-analysis was performed based on 5 randomized studies. Regarding patients with alopecia areata defined as ≥ 50% scalp hair loss, baricitinib 4 mg once daily demonstrated the highest efficacy. However, among patients with alopecia areata defined as a SALT score ≥ 50, oral deuruxolitinib 12 mg twice daily demonstrated the highest efficacy. Deuruxolitinib and baricitinib appear to be promising drugs for the treatment of alopecia areata. However, the response depends on the dosage of the drug. More randomized trials, with identical inclusion criteria and dose and duration of treatment, are required to confirm these findings.

Alopecia Areata: Case report and review of pathophysiology and treatment with Jak inhibitors

Alopecia Areata (AA) is a T-cell mediated autoimmune attack on hair follicles resulting in rapidly developing areas of hair loss involving the scalp and beard that can progress to total scalp hair loss (alopecia totalis) and loss of eyebrows, eyelashes, and total body hair (alopecia universalis). Affected patients have high rates of psychological disorders and decreased quality of life. There are no FDA approved treatments, and the available treatments have a high failure rate. JAK inhibitors are remarkably effective in many autoimmune diseases including Alopecia Areata. Presented is a case report of successful treatment with tofacitinib, and a literature review of the pathophysiology of alopecia areata, the mechanism of action of JAK inhibitors, and the JAK inhibitors in phase 2 and 3 trials.

Real-world experience and long-term evaluation of tofacitinib in refractory alopecia areata: A prospective, open-label, single-center study in Asian Arab population

Tofacitinib is a pan-janus kinase inhibitor (JAK) which has been tested off-label in alopecia areata (AA) with promising results. However, evidence of tofacitinib in real-life setting is still poor. We evaluated long-term efficacy and safety of tofacitinib for refractory AA. This is a prospective, open-label, observational, single-center cohort study conducted between January 2018 and December 2020. Primary end-point was the percent change in Severity of Alopecia Tool (SALT) at the basal visit and at the most recent follow-up visit. Three categories of treatment response were analyzed. Data on 47 participants of Arab-Asian heritage were analyzed. A complete and partial regrowth was observed in 18 patients (41.86%) and 11 patients (25.58%), respectively. In 12 patients (27.9%), no response was obtained. Most of the non-responders belonged to the alopecia universalis group (66.67%). No statistical differences were observed in rates of regrowth between pediatric and adult individuals (p = 0.52), nor between women and men. Significant differences in the average duration of tofacitinib treatment were obtained among the three categories of regrowth (p < 0.003), notably duration of AA did not impact the clinical regrowth (p = 0.62). To the best of our knowledge, this is the first prospective, observational, long-term study using tofacitinib in refractory AA. Rates of regrowth and side effects are analogous to previous works. Length of tofacinitib therapy should last for 12 months before considering any discontinuation or change, since early cessation can lead to treatment failures or incomplete regrowth. Maintenance therapy after complete regrowth has demonstrated to be safe and effective to prevent recurrences of hair loss.

Emerging drugs for the treatment of alopecia areata

INTRODUCTION

Alopecia Areata (AA) is the second most common non-scarring hair loss disorder, with a prevalence of 1 in 1000 and a lifetime incidence of 2% worldwide. Data from a recent American study shows that from 68,121 patients with the diagnosis of AA, 37,995 (55.8%) were prescribed treatment for AA within a year of diagnosis, however there are still no therapies able to induce permanent remission, or treatments that guarantee hair regrowth/remissions in 100% of cases, especially in longstanding/severe AA. Recently, oral baricitinib has been approved for AA, being the first drug approved for this specific indication.

AREAS COVERED

The current review will provide a summary of current pharmacological approaches and novel therapeutics in development.

EXPERT OPINION

New and very effective drugs have become available for the treatment of severe AA, and many others are expected soon. However, even new, effective treatments are not effective in all patients and recurrence rates after treatment interruption are high. AA is a systemic disease with important impact on quality of life and should not be considered just as an aesthetic problem. Treatment of the disease should take in account and possibly also address treatment of comorbidities.

Induction of T cell exhaustion by JAK1/3 inhibition in the treatment of alopecia areata

Alopecia areata (AA) is an autoimmune disease caused by T cell-mediated destruction of the hair follicle (HF). Therefore, approaches that effectively disrupt pathogenic T cell responses are predicted to have therapeutic benefit for AA treatment. T cells rely on the duality of T cell receptor (TCR) and gamma chain (γc) cytokine signaling for their development, activation, and peripheral homeostasis. Ifidancitinib is a potent and selective next-generation JAK1/3 inhibitor predicted to disrupt γc cytokine signaling. We found that Ifidancitinib robustly induced hair regrowth in AA-affected C3H/HeJ mice when fed with Ifidancitinib in chow diets. Skin taken from Ifidancitinib-treated mice showed significantly decreased AA-associated inflammation. CD44⁺CD62L^- CD8⁺ T effector/memory cells, which are associated with the pathogenesis of AA, were significantly decreased in the peripheral lymphoid organs in Ifidancitinib-treated mice. We observed high expression of co-inhibitory receptors PD-1 on effector/memory CD8⁺ T cells, together with decreased IFN-γ production in Ifidancitinib-treated mice. Furthermore, we found that γc cytokines regulated T cell exhaustion. Taken together, our data indicate that selective induction of T cell exhaustion using a JAK inhibitor may offer a mechanistic explanation for the success of this treatment strategy in the reversal of autoimmune diseases such as AA.

An overview of JAK/STAT pathways and JAK inhibition in alopecia areata

Alopecia Areata (AA) is a common autoimmune disease characterized by non-scarring hair loss ranging from patches on the scalp to complete hair loss involving the entire body. Disease onset is hypothesized to follow the collapse of immune privilege of the hair follicle, which results in an increase in self-peptide/MHC expression along the follicular epithelium. Hair loss is associated with infiltration of the hair follicle with putatively self-reactive T cells. This process is thought to skew the hair follicle microenvironment away from a typically homeostatic immune state towards one of active inflammation. This imbalance is mediated in part by the dominating presence of specific cytokines. While interferon-γ (IFNγ) has been identified as the key player in AA pathogenesis, many other cytokines have also been shown to play pivotal roles. Mechanistic studies in animal models have highlighted the contribution of common gamma chain (γ_c) cytokines such as IL-2, IL-7, and IL-15 in augmenting disease. IFNγ and γ_c cytokines signal through pathways involving receptor activation of Janus kinases (JAKs) and signal transducers and activators of transcription (STATs). Based on these findings, JAK/STAT pathways have been targeted for the purposes of therapeutic intervention in the clinical setting. Case reports and series have described use of small molecule JAK inhibitors leading to hair regrowth among AA patients. Furthermore, emerging clinical trial results show great promise and position JAK inhibitors as a treatment strategy for patients with severe or recalcitrant disease. Demonstrated efficacy from large-scale clinical trials of the JAK inhibitor baricitinib led to the first-in-disease FDA-approved treatment for AA in June of 2022. This review aims to highlight the JAK/STAT signaling pathways of various cytokines involved in AA and how targeting those pathways may impact disease outcomes in both laboratory and clinical settings.

The efficacy and safety of JAK inhibitors for alopecia areata: A systematic review and meta-analysis of prospective studies

Background: Due to the lack of comprehensive evidence based on prospective studies, the efficacy and safety of Janus Kinase (JAK) inhibitors (including tofacitinib, ruxolitinib, baricitinib, ritlecitinib and brepocitinib) for alopecia areata (AA) are yet to be proved.

Methods: The systematic review and meta-analysis was performed pursuant to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guideline and registered on PROSPERO (CRD42022303007).

Results: Fourteen prospective studies (5 RCTs and 9 non-RCTs), enrolling a total of 1845 patients with AA, were included for quantitative analysis. In RCTs, oral JAK inhibitors resulted in higher good response rate compared with control (RR: 6.86, 95% CI: 2.91–16.16); topical JAK inhibitors did not show any difference compared with control (RR: 1.00, 95% CI: 0.31–3.18). In non-RCTs, the pooled rate of good response to oral, topical and sublingual JAK inhibitors were 63% (95% CI: 44%–80%), 28% (95% CI: 1%–72%) and 11% (95% CI: 1%–29%), respectively. The pooled recurrence rate in patients treated with JAK inhibitors was 54% (95% CI: 39%–69%), mainly due to the withdrawal of JAK inhibitors. In RCTs, no difference was found in the risk of experiencing most kind of adverse events; in non-RCTs, the reported adverse events with high incidence rate were mostly mild and manageable.

Conclusion: JAK inhibitors are efficacious and generally well-tolerated in treating AA with oral administration, whereas topical or sublingual administration lacks efficacy. Subgroup analyses indicate that baricitinib, ritlecitinib and brepocitinib seem to have equal efficacy for AA in RCTs; ruxolitinib (vs. tofacitinib) and AA (vs. AT/AU) are associated with better efficacy outcomes in non-RCT. Due to the high recurrence rate after withdrawal of JAK inhibitors, continuous treatment should be considered to maintain efficacy.

Systematic Review Registration: PROSPERO: CRD 42022303007

Primary cicatricial alopecias are characterized by dysregulation of shared gene expression pathways

The primary forms of cicatricial (scarring) alopecia (PCA) are a group of inflammatory, irreversible hair loss disorders characterized by immune cell infiltrates targeting hair follicles (HFs). Lichen planopilaris (LPP), frontal fibrosing alopecia (FFA), and centrifugal cicatricial alopecia (CCCA) are among the main subtypes of PCAs. The pathogenesis of the different types of PCAs are poorly understood, and current treatment regimens yield inconsistent and unsatisfactory results. We performed high-throughput RNA-sequencing on scalp biopsies of a large cohort PCA patients to develop gene expression-based signatures, trained into machine-learning-based predictive models and pathways associated with dysregulated gene expression. We performed morphological and cytokine analysis to define the immune cell populations found in PCA subtypes. We identified a common PCA gene signature that was shared between LPP, FFA, and CCCA, which revealed a significant over-representation of mast cell (MC) genes, as well as downregulation of cholesterogenic pathways and upregulation of fibrosis and immune signaling genes. Immunohistological analyses revealed an increased presence of MCs in PCAs lesions. Our gene expression analyses revealed common pathways associated with PCAs, with a strong association with MCs. The indistinguishable differences in gene expression profiles and immune cell signatures between LPP, FFA, and CCCA suggest that similar treatment regimens may be effective in treating these irreversible forms of hair loss.

Translational impact of omics studies in alopecia areata: recent advances and future perspectives

INTRODUCTION

Alopecia areata (AA) is a non-scarring, hair loss disorder and a common autoimmune-mediated disease with an estimated lifetime risk of about 2%. To date, the treatment of AA is mainly based on suppression or stimulation of the immune response. Genomics and transcriptomics studies generated important insights into the underlying pathophysiology, enabled discovery of molecular disease signatures, which were used in some of the recent clinical trials to monitor drug response and substantiated the consideration of new therapeutic modalities for the treatment of AA such as abatacept, dupilumab, ustekinumab and Janus Kinase (JAK) inhibitors.

AREAS COVERED

In this review, genomics and transcriptomics studies in AA are discussed in detail with particular emphasis on their past and prospective translational impacts. Microbiome studies are also briefly introduced.

EXPERT OPINION

The generation of large datasets using the new high-throughput technologies has revolutionized medical research and AA has also benefited from the wave of omics studies. However, the limitations associated with JAK inhibitors and clinical heterogeneity in AA patients underscore the necessity for continuing omics research in AA for discovery of novel therapeutic modalities and development of clinical tools for precision medicine.

Refractory alopecia universalis associated with dermatomyositis successfully treated with tofacitinib

Dermatomyositis (DM) and alopecia areata are two diseases characterised by aberrant interferon signalling. While patchy alopecia of the scalp is a known feature of DM, alopecia universalis, which involves hair loss over the entire body, has rarely been reported in conjunction with DM. Herein, we report the case of a 30-year-old female with DM who developed refractory cutaneous disease and alopecia universalis that were successfully treated with tofacitinib. This could suggest that concomitant severe alopecia and refractory cutaneous DM may reflect a strong baseline interferon gene signature that may predict responsiveness to janus kinase inhibitors.

Unmet Medical Needs in Chronic, Non-communicable Inflammatory Skin Diseases

An estimated 20-25% of the population is affected by chronic, non-communicable inflammatory skin diseases. Chronic skin inflammation has many causes. Among the most frequent chronic inflammatory skin diseases are atopic dermatitis, psoriasis, urticaria, lichen planus, and hidradenitis suppurativa, driven by a complex interplay of genetics and environmental factors. Autoimmunity is another important cause of chronic skin inflammation. The autoimmune response may be mainly T cell driven, such as in alopecia areata or vitiligo, or B cell driven in chronic spontaneous urticaria, pemphigus and pemphigoid diseases. Rare causes of chronic skin inflammation are autoinflammatory diseases, or rheumatic diseases, such as cutaneous lupus erythematosus or dermatomyositis. Whilst we have seen a significant improvement in diagnosis and treatment, several challenges remain. Especially for rarer causes of chronic skin inflammation, early diagnosis is often missed because of low awareness and lack of diagnostics. Systemic immunosuppression is the treatment of choice for almost all of these diseases. Adverse events due to immunosuppression, insufficient therapeutic responses and relapses remain a challenge. For atopic dermatitis and psoriasis, a broad spectrum of innovative treatments has been developed. However, treatment responses cannot be predicted so far. Hence, development of (bio)markers allowing selection of specific medications for individual patients is needed. Given the encouraging developments during the past years, we envision that many of these challenges in the diagnosis and treatment of chronic inflammatory skin diseases will be thoroughly addressed in the future.

Two Phase 3 Trials of Baricitinib for Alopecia Areata

BACKGROUND

Alopecia areata is an autoimmune condition characterized by rapid hair loss in the scalp, eyebrows, and eyelashes, for which treatments are limited. Baricitinib, an oral, selective, reversible inhibitor of Janus kinases 1 and 2, may interrupt cytokine signaling implicated in the pathogenesis of alopecia areata.

METHODS

We conducted two randomized, placebo-controlled, phase 3 trials (BRAVE-AA1 and BRAVE-AA2) involving adults with severe alopecia areata with a Severity of Alopecia Tool (SALT) score of 50 or higher (range, 0 [no scalp hair loss] to 100 [complete scalp hair loss]). Patients were randomly assigned in a 3:2:2 ratio to receive once-daily baricitinib at a dose of 4 mg, baricitinib at a dose of 2 mg, or placebo. The primary outcome was a SALT score of 20 or less at week 36.

RESULTS

We enrolled 654 patients in the BRAVE-AA1 trial and 546 in the BRAVE-AA2 trial. The estimated percentage of patients with a SALT score of 20 or less at week 36 was 38.8% with 4-mg baricitinib, 22.8% with 2-mg baricitinib, and 6.2% with placebo in BRAVE-AA1 and 35.9%, 19.4%, and 3.3%, respectively, in BRAVE-AA2. In BRAVE-AA1, the difference between 4-mg baricitinib and placebo was 32.6 percentage points (95% confidence interval [CI], 25.6 to 39.5), and the difference between 2-mg baricitinib and placebo was 16.6 percentage points (95% CI, 9.5 to 23.8) (P<0.001 for each dose vs. placebo). In BRAVE-AA2, the corresponding values were 32.6 percentage points (95% CI, 25.6 to 39.6) and 16.1 percentage points (95% CI, 9.1 to 23.2) (P<0.001 for each dose vs. placebo). Secondary outcomes for baricitinib at a dose of 4 mg but not at a dose of 2 mg generally favored baricitinib over placebo. Acne, elevated levels of creatine kinase, and increased levels of low- and high-density lipoprotein cholesterol were more common with baricitinib than with placebo.

CONCLUSIONS

In two phase 3 trials involving patients with severe alopecia areata, oral baricitinib was superior to placebo with respect to hair regrowth at 36 weeks. Longer trials are required to assess the efficacy and safety of baricitinib for alopecia areata. (Funded by Eli Lilly under license from Incyte; BRAVE-AA1 and BRAVE-AA2 ClinicalTrials.gov numbers, NCT03570749 and NCT03899259.).

[Janus kinase inhibitors for the treatment of alopecia areata]

Alopecia areata is a common condition that leads to nonscarring hair loss. It can be severe and lead to complete hair loss of the scalp or the whole body. In more severe cases, the disease can be very recalcitrant to treatment and result in a significant impairment of the quality of life of the patients. In recent years, there is increasing evidence on the potential of janus kinase (JAK) inhibitors to treat alopecia areata. In the beginning, this was based on case reports, but later, this potential was further established by large case series and in vitro and in vivo data. It is on this basis that JAK inhibitors are being tested specifically for the treatment of alopecia areata in phase 3, randomized, placebo-controlled trials, raising hopes that there will soon be a JAK inhibitor approved by the US Food and Drug Administration (FDA) for the treatment of alopecia areata. Here we provide a review of the information available on the use of JAK inhibitors to treat alopecia areata, and the potential benefits and risks of this class of medications.

Evaluating the Therapeutic Potential of Ritlecitinib for the Treatment of Alopecia Areata

Alopecia areata (AA) is an autoimmune condition that causes patchy hair loss, affecting up to 147 million people globally. Currently, there are no treatments approved by US Food and Drug Administration (FDA) specific for AA, and there are few effective therapeutic options for widespread and persistent illness. There is an ongoing need for a treatment that demonstrates a good clinical response with a benefit-risk ratio that is suitable for long-term use, especially for patients with chronic, extensive disease. Several clinical trials and case studies that have assessed Janus kinase inhibitors have had encouraging results. Ritlecitinib, a selective JAK3/TEC kinase inhibitor has been demonstrated to inhibit the action of signaling molecules and immune cells that are responsible for hair loss in people with alopecia areata. Furthermore, several clinical trials are investigating the utility of ritlecitinib in patients with vitiligo, rheumatoid arthritis, Crohn’s disease, and ulcerative colitis. Advantages of using ritlecitinib when compared with other non-selective JAK inhibitors include avoiding JAK1/JAK2 inhibition’s clinical repercussions, which include pharmacodynamic effects such as increased cholesterol and liver enzymes, and those related to JAK2 inhibition (thrombocytopenia, anemia). Treatment with Ritlecitinib 50 mg and 30 mg daily for 24 weeks has been shown to induce hair regrowth with a significant proportion of patients reaching SALT 20 (≤20% scalp hair loss) after six months of therapy compared to placebo. Additional research is needed for long-term effects.

Phase 2a randomized clinical trial of dupilumab (anti-IL-4Rα) for alopecia areata patients

BACKGROUND

Treatments for alopecia areata (AA) patients with extensive scalp hair loss are limited, and recent evidence supports a role for type 2 T-cell (Th2)-immune response in AA. Dupilumab, a monoclonal antibody inhibiting Th2 signaling, approved for type 2 diseases including atopic dermatitis, was evaluated in AA patients.

METHODS

Alopecia areata patients with and without concomitant atopic dermatitis were randomized 2:1 to receive weekly subcutaneous dupilumab (300 mg) or placebo for 24 weeks, followed by another 24-week dupilumab open-label phase. The primary outcome was change from baseline in the Severity of Alopecia Tool (SALT) score at week 24; secondary outcomes included a range of measures of hair regrowth.

RESULTS

Forty and 20 patients were assigned to the dupilumab and placebo arms, respectively. At week 24, disease worsening was documented in the placebo arm, with a least-squares mean change in the SALT score of -6.5 (95% confidence-interval [CI], -10.4 to -2.6), versus a change of 2.2 (95% CI, -0.6 to 4.94) in the dupilumab arm (p < .05). After 48 weeks of dupilumab treatment, 32.5%, 22.5% and 15% of patients achieved SALT₃₀ /SALT₅₀ /SALT₇₅ improvement, respectively, while in patients with baseline IgE ≥ 200 IU/ml response rates increased to 53.8%, 46.2%, and 38.5%, respectively. Moreover, baseline IgE predicts treatment response with 83% accuracy. No new safety signals were detected.

CONCLUSIONS

This hypothesis-driven trial is the first to indicate the possible pathogenic role of the Th2 axis and Th2 targeting in AA patients. Patient selection based on baseline serum IgE levels may improve treatment results (Clinicaltrials.gov number, NCT03359356).