The role of Janus kinase inhibitors in the treatment of alopecia areata: A systematic review

Small molecule agents against alopecia: Potential targets and related pathways

Alopecia has emerged as a global concern, extending beyond the middle-aged and elderly population and increasingly affecting younger individuals. Despite its growing prevalence, the treatment options and effective drugs for alopecia remain limited due to the incomplete understanding of its underlying mechanisms. Therefore, it is urgent to explore the pathogenesis of alopecia and discover novel and safer therapeutic agents. This review provided an overview of the prevailing clinical disorders of alopecia, and the key pathways and targets involved in hair growth process. Additionally, it discusses FDA-approved drugs and clinical candidates for the treatment of alopecia, and explores small molecule compounds with anti-alopecia potential in the drug discovery phase. These endeavors are expected to provide researchers with valuable scientific insights and practical information for anti-alopecia drug discovery.

Exploring Janus kinase inhibitors for alopecia areata: a comprehensive review

INTRODUCTION

Alopecia areata poses a significant challenge due to its chronic autoimmune nature, leading to psychosocial impacts. Recent strides in understanding the disease have spotlighted Janus kinase (JAK) inhibitors as potential therapies. This comprehensive review aims to assess Baricitinib's efficacy and safety in treating scalp, eyebrow, and eyelash alopecia areata, and compare the effectiveness of Ritlecitinib and Brepocitinib.

EVIDENCE ACQUISITION

Conducting a thorough electronic literature search, we focused on clinical studies of JAK inhibitors for moderate to severe alopecia areata from 2015 onward. Key databases, including MEDLINE, PubMed, Cochrane Library, EMBASE, Google Scholar, and Medscape, were utilized. Primary outcomes included changes in the Severity of Alopecia Tool (SALT) score, with safety data evaluating adverse events and serious adverse events. The risk of bias was assessed using the Cochrane Risk of Bias Tool.

EVIDENCE SYNTHESIS

Among the twelve studies identified, Baricitinib demonstrated superior efficacy over placebo at 24 weeks, with both 2mg and 4mg dosages significantly reducing SALT scores. Comparative efficacy at 24 weeks for Baricitinib, Brepocitinib, and Ritlecitinib showed similar effectiveness compared to placebo, with a marginal superiority observed for Baricitinib 4mg. All JAK inhibitors were well-tolerated, with reported adverse events primarily being mild and manageable.

CONCLUSIONS

Collectively, the reviewed studies affirm JAK inhibitors, particularly Baricitinib, as promising treatments for moderate to severe alopecia areata. These inhibitors exhibit superior efficacy, as indicated by notable reductions in SALT scores, and are well-tolerated, with predominantly mild and manageable adverse events.

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.

SOCS1 and SOCS3 as key checkpoint molecules in the immune responses associated to skin inflammation and malignant transformation

SOCS are a family of negative inhibitors of the molecular cascades induced by cytokines, growth factors and hormones. At molecular level, SOCS proteins inhibit the kinase activity of specific sets of receptor-associated Janus Activated Kinases (JAKs), thereby suppressing the propagation of intracellular signals. Of the eight known members, SOCS1 and SOCS3 inhibit activity of JAKs mainly induced by cytokines and can play key roles in regulation of inflammatory and immune responses. SOCS1 and SOCS3 are the most well-characterized SOCS members in skin inflammatory diseases, where their inhibitory activity on cytokine activated JAKs and consequent anti-inflammatory action has been widely investigated in epidermal keratinocytes. Structurally, SOCS1 and SOCS3 share the presence of a N-terminal domain containing a kinase inhibitory region (KIR) motif able to act as a pseudo-substrate for JAK and to inhibit its activity. During the last decades, the design and employment of SOCS1 and SOCS3-derived peptides mimicking KIR domains in experimental models of dermatoses definitively established a strong anti-inflammatory and ameliorative impact of JAK inhibition on skin inflammatory responses. Herein, we discuss the importance of the findings collected in the past on SOCS1 and SOCS3 function in the inflammatory responses associated to skin immune-mediated diseases and malignancies, for the development of the JAK inhibitor drugs. Among them, different JAK inhibitors have been introduced in the clinical practice for treatment of atopic dermatitis and psoriasis, and others are being investigated for skin diseases like alopecia areata and vitiligo.

Comparative efficacy of oral Janus kinase inhibitors and biologics in adult alopecia areata: A systematic review and Bayesian network meta-analysis

Alopecia areata (AA) is an autoimmune disorder that affects the hair follicles, resulting in patchy recurrent hair loss. A large body of evidence has demonstrated the favourable clinical response of the Janus kinase (JAK) inhibitors and biologics, but a lack of comprehensive comparison among these therapies exists in the current literature. This study aimed to compare their efficacy. A systematic review and meta-analysis were performed including randomized trials that report the outcomes of the Severity of Alopecia Tool (SALT)50 and/or the mean change in SALT. These articles were pooled and a network meta-analysis (NAM) was conducted. Based on the surface under the cumulative ranking curve estimates obtained for the mean change in SALT score, baricitinib_4 mg (0.7949656) had the best probability of being the most effective therapy, followed by ritlecitinib_200_50 mg (0.7391906) and ivarmacitinib_4 mg (0.7292594). In contrast, dupilumab, secukinumab, tralokinumab and apremilast were less likely to be effective. Targeting the JAK signalling pathway holds great potential for restoring hair regrowth, albeit the contribution of JAK1, JAK2, JAK3 and TYK2 inhibition to the therapeutic effect on AA is apparently different. Baricitinib_4 mg and ritlecitinib 200_50 mg demonstrated notable efficacy, and both molecules displayed a dose-dependent effect, which is not observed with ivarmacitinib. Further investigations into the specific mechanisms of action of these JAK inhibitors are warranted to elucidate the reasons behind these differences.

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.

Case Report: A Case of Myeloproliferative Neoplasm Complicated by Alopecia Areata

Myeloproliferative neoplasms (MPNs) are caused by genetic abnormalities in the stem cells and manifest with various systemic symptoms. Here, we describe a case of MPN complicated by alopecia areata. A 51-year-old woman visited our hematology department for further evaluation of a slight platelet elevation. Her recent medical history included 3 years of concurrent severe alopecia, mild fatigue, and hot flashes but no fever and weight loss. Physical examination revealed unilateral hair loss on the entire body but no hepatosplenomegaly. Laboratory analysis revealed a normal hemoglobin level, normal white blood cell count, and platelet count of 377,000/μL. Genetic testing confirmed the presence of the JAK2 V617F mutation. Bone marrow examination revealed no morphologic dysplasia in any stem cell lineage and no fibrotic change. Skin biopsy revealed lymphocyte infiltration around the hair follicles. We diagnosed MPN, unclassifiable, which was believed to be the cause of alopecia. About 6 months after treatment with ruxolitinib began, the patient's hair growth dramatically improved. The differential diagnosis of MPNs should include hematological diseases when affected patients have alopecia areata.

Systematic review - alopecia areata and tofacitinib in paediatric patients

INTRODUCTION

Alopecia Areata is a nonscarring hair loss disorder and is the most common hair loss cause in children. It is a chronic autoimmune disorder with a severe psychological impact in patients' lives. JAK inhibitors, in particular Tofacitinib, have been having promising results on Alopecia Areata Treatment. In this study we aimed to do a Systematic Review on the role of Tofacitinib (either orally or topically), considering efficacy and safety, in treating children with Alopecia Areata.

MATERIALS AND METHODS

PubMed, Cochrane and Web of Science databases were searched (up to 1st of September of 2021) looking for Tofacitinib (all text/all fields) and MeSH/Keyword term Alopecia Areata.

RESULTS AND CONCLUSIONS

We included 14 studies and 64 cases in the Systematic Review. From these, 12 were considering systemic administration (47 patients) and two were considering topical administration (17 patients). Responsiveness was as high as 81.3%. The responsiveness was similar among different genders (78.6% in males and 80.0% in females) and either whether administration was topic (70.6% responsiveness) or systemic (85.1% responsiveness). Adverse effects were rare and, when present, were mild. Studies shows promising results in what considers the efficacy and safety of Tofacitinib in the treatment of Alopecia Areata. As the available evidence to date is of low quality, further randomised studies are required to confirm these findings.

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.).

The current state of knowledge of the immune ecosystem in alopecia areata

Alopecia areata (AA) is an autoimmune disease that affects approximately 2% of the general population. Patients with AA most commonly present with one or more patches of hair loss on the scalp in defined circular areas. A fraction of patients progress to more severe forms of the disease, in some cases with involvement of all body surfaces. The healthy anagen stage hair follicle is considered an immune privileged site, described as an environment that suppresses inflammatory immune responses. However, in AA, this immune privileged state collapses and marks the hair follicle as a target for the immune system, resulting in peri- and intrafollicular infiltration by lymphocytes. The complexity of the inflammatory ecosystem of the immune response to the hair follicle, and the relationships between the cellular and soluble participants, in AA remains incompletely understood. Many studies have demonstrated the presence of various immune cells around diseased hair follicles; however, often little is known about their respective contributions to AA pathogenesis. Furthering our understanding of the mechanisms of disease in AA is essential for the novel identification of targeted therapeutics that are efficacious and have few unintended effects.

[Alopecia areata with good response to tofacitinib]

We present a case of a 46-year-old woman suffering from active inflammatory alopecia areata universalis. After frustrating use of topical and systemic glucocorticoids, cream PUVA (psoralen and ultraviolet A) therapy and dithranol in increasing dosage, the patient was treated with 2 × 5 mg per day tofacitinib per os. After about 4-6 months, hair growth commenced, which led to full regrowth of scalp hair over the 18 months of therapy, which was well tolerated. The case shows impressively that the off-label application of tofacitinib is a therapeutic option for alopecia areata.

The status and outcomes of registered clinical trials for Janus kinase inhibitors in alopecia areata: are unpublished trials being overlooked?

Recent meta-analyses of Janus kinase (JAK) inhibitors in alopecia areata (AA) have excluded trial registries and may thus be subject to publication bias. This study assessed the potential for evidence selection bias and provides an overview of JAK inhibitor trials in AA. A broad search strategy of ClinicalTrials.gov was performed for AA. We also recorded whether results were published on PubMed. There were 26 trials identified, of which 9 were ongoing (mostly oral JAK inhibitors: 8 studies; 89%). Of completed/terminated trials, 4/17 (24%) had terminated prematurely, citing 'inefficacy/futility' or 'sponsor decision'. These were all topical JAK inhibitor trials (4/8, 50% termination rate), with a 0% termination rate (0/9) for oral JAK inhibitor trials. We conclude that topical JAK inhibitors may be less efficacious than has been apparent in the literature to date, with 50% of trials having terminated due to inefficacy/futility or sponsor decision and only one topical JAK inhibitor trial ongoing.

Experience with oral tofacitinib in severe alopecia areata with different clinical responses

BACKGROUND

Alopecia areata (AA) and generalized form, universalis (AU) are common causes of noncicatricial alopecia, targeting anagen hair follicles. A dominant interferon-gamma transcriptional signaling and cytotoxic T lymphocytes were accused as the main drivers of disease pathogenesis. Tofacitinib is a Janus kinase inhibitor that has been proven to interfere with the positive feedback loop between the follicular cell and the cytotoxic T lymphocytes in AA. There is an increasing number of studies reporting success with tofacitinib in AA.

AIMS

We aimed to assess oral tofacitinib's safety and efficacy in 13 recalcitrant AA and AU patients.

METHODS

This is a retrospective pilot study performed between 2017 and 2020. The demographic features and the treatment responses were evaluated with Severity of Alopecia Tool score changes.

RESULTS

Thirteen recalcitrant alopecia areata patients (3 AA, 10 AU), aged between 17 and 49, were included in the study. The treatment duration was 3-15 months. All three AA patients responded well; however, the therapy was unsuccessful in five of ten AU patients. Relapse was observed in one of the AA and three of the AU responders. Acneiform lesions and elevation of transaminases were the major side effects.

CONCLUSION

Tofacitinib seems to be more promising and thriving in the treatment of AA than AU. Starting the therapy earlier can bring more successful results. Unfortunately, even in the cases that fully respond to treatment, relapse can be observed after discontinuation of the treatment. It is essential to inform patients about this situation in reducing the frustrations that may occur later.

Cumulative Life Course Impairment of Alopecia Areata

Alopecia areata (AA), an unpredictable, nonscarring hair loss, is commonly perceived as a cosmetic, rather than medical, concern. However, substantial evidence exists describing the negative impact on quality of life, as the disease affects patients personally, socially, financially, and physically. Over time, the cumulative disability may perpetuate poor confidence, social disconnection, negative coping strategies, and failure to achieve a full life potential. Here, we describe the cumulative life course impairment (CLCI) of AA by examining the complex interaction of (1) stigmatization, (2) physical and psychiatric comorbidities, and (3) coping strategies. The model aggregates existing cross-sectional data, which have previously captured disease burden only as snapshots in time. Thus, by examining cumulative effects, the CLCI model serves as a proxy for longitudinal data to better describe life course epidemiology of the disease.

Consensus on the treatment of alopecia areata - Brazilian Society of Dermatology

BACKGROUND

Alopecia areata is a highly frequent disease with an impact on quality of life and several treatment options with little clinical confirmatory evidence.

OBJECTIVE

To disseminate the recommendations of Brazilian dermatologists with expertise in the treatment of alopecia areata.

METHODS

Eight specialists with expertise in alopecia areata from different university centers were appointed by the Brazilian Society of Dermatology to reach a consensus on its treatment. Based on the adapted DELPHI methodology, the relevant elements were considered; then, an analysis of recent literature was carried out and the consensus was written down. Consensus on the management of alopecia areata was defined with the approval of at least 70% of the panel.

RESULTS/CONCLUSIONS

Intralesional injectable corticotherapy was considered the first option for localized disease in adults. In extensive cases with signs of activity, systemic corticosteroid therapy should be considered and can be used together with immunosuppressants (corticosteroid-sparing agents). The use of an immunosensitizer (diphencyprone) is an option for stable long-term cases. Evaluation of side effects is as important as the rate of hair regrowth.

Hair Growth Effect of Emulsion Extracted Brevilin A, a JAK3 Inhibitor, from Centipeda minima

Janus kinase 3 (JAK3) inhibitors have been used effectively in the treatment of several cases of alopecia universalis and its variants. Our study aims to evaluate whether the emulsion extract of brevilin A from Centipeda minima (CMX) stimulates hair regrowth in a clinical trial, as a JAK3 inhibitor, combined with network pharmacology-based analysis. CMX showed potent inhibition of JAK3 in a concentration-dependent manner. Significant differences in total hair count, terminal hair count, and anagen hair count from the baseline to 24 weeks were observed between the placebo and CMX subjects. The gene set enrichment analysis showed that the targets of CMX are mainly associated with the JAK-STAT signaling pathway, cytokine–cytokine receptor interactions, and the MAPK signaling pathway. This study suggests that the medicinal herbal extract CMX is useful in the treatment of mild to moderate vertex balding that contribute to the visible improvements in hair growth observed in treated patients.

Scoping Review on the Use of Drugs Targeting JAK/STAT Pathway in Atopic Dermatitis, Vitiligo, and Alopecia Areata

INTRODUCTION

The JAK/STAT signaling pathway is involved in the immune-mediated inflammatory skin diseases atopic dermatitis (AD), vitiligo, and alopecia areata (AA), and represents a potential target when developing treatments. So far, no drugs targeting this pathway have been approved for the treatment of dermatological diseases. We reviewed the use of drugs blocking the JAK/STAT pathway in the aforementioned diseases.

METHODS

An a priori protocol was published. We used Joanna Briggs Institute Reviewer's Manual methodology to conduct the review and PRISMA Extension for Scoping Review (PRISMA-ScR) to report results. MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science databases were searched in a three-step approach on April 2019 by two researchers.

RESULTS

Ninety-six mainly multicenter observational studies were included (66, 10, and 20 studies on AA, vitiligo, and AD, respectively). Tofacitinib and ruxolitinib were mainly used for the three diseases, and also upadacitinib, abrocitinib, baricitinib, cerdulatinib, delgocitinib, gusacitinib for AD, and baricitinib, PF-06700841, and PF-06651600 for AA. All patients with AD improved, whereas patients with vitiligo and patients with AA showed varied responses, including unresponsive cases. The safety profiles were similar for all drugs and diseases, mainly comprising mild or no adverse events.

CONCLUSIONS

Evidence on the efficacy and safety of drugs targeting the JAK/STAT pathway for the treatment of patients with AD, vitiligo, or AA is increasing but is still of low quality.