Rebound effect associated with JAK inhibitor use in the treatment of 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.

Long-Term Safety Profile and Off-Label Use of JAK Inhibitors in Dermatological Disorders

JAK inhibitors target specific inflammatory cytokines involved in various inflammatory diseases. Four molecules have been approved for dermatological use: upadacitinib, baricitinib, abrocitinib and topical ruxolitinib. Off-label prescriptions for other dermatological conditions have been reported. We conducted a narrative review of the literature to assess the long-term safety profile of currently approved JAK inhibitors in dermatology, and their off-label use in skin disorders. We performed literature searches with PubMed and Google Scholar from January 2000 to January 2023, using the keywords "Janus kinase inhibitors", "JAK inhibitors","off-label", "dermatology", "safety", "adverse events", "ruxolitinib", "upadacitinib","abrocitinib" and "baricitinib". Our search yielded a total of 37 dermatological disorders with studies supporting the use of these JAK inhibitors. Preliminary studies indicate that JAK inhibitors generally have a favorable safety profile and can be considered as an option in many dermatological disorders.

Long-Term Safety Profile and Off-Label Use of JAK Inhibitors in Dermatological Disorders

JAK inhibitors target specific inflammatory cytokines involved in various inflammatory diseases. Four molecules have been approved for dermatological use: upadacitinib, baricitinib, abrocitinib and topical ruxolitinib. Off-label prescriptions for other dermatological conditions have been reported. We conducted a narrative review of the literature to assess the long-term safety profile of currently approved JAK inhibitors in dermatology, and their off-label use in skin disorders. We performed literature searches with Pubmed and Google Scholar from January 2000 to January 2023, using the keywords "Janus kinase inhibitors", "JAK inhibitors", "off-label", "dermatology", "safety", "adverse events", "ruxolitinib", "upadacitinib", "abrocitinib" and "baricitinib". Our search yielded a total of 37 dermatological disorders with studies supporting the use of these JAK inhibitors. Preliminary studies indicate that JAK inhibitors generally have a favorable safety profile and can be considered as an option in many dermatological disorders.

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.

Effectiveness of Oral Tofacitinib Dose Tapering in a Case of Alopecia Areata Universalis

Introduction

Alopecia areata (AA) is a form of nonscarring alopecia and one of the most common autoimmune disorders. Persistent or severe variants lead to potential disfigurement and are associated with a significant negative impact on the patient's quality of life.

Case Presentation

A 51-year-old female patient presenting with refractory alopecia universalis was successfully treated with oral tofacitinib. Recurrence was not observed following 17 months of therapy.

Discussion/Conclusion

None of the currently employed therapies for AA are reliably effective nor are they approved for the disease. In this setting, Janus kinase inhibitors emerge as a promising novel treatment, as increasing evidence supports their effectiveness in AA.

Evaluation of the alopecia areata patients on tofacitinib treatment during the COVID-19 pandemic

Tofacitinib is a Janus Kinase 3 inhibitor that is used in the treatment of alopecia areata. We recommended our alopecia areata patients to discontinue their tofacitinib treatment during the COVID‐19 pandemic for an average of 80 days. We aimed to evaluate the drug use and the SARS‐CoV‐2 infection status of alopecia areata patients; and the relationships of recurrence to age, gender, treatment duration, and tofacitinib discontinuation. One‐hundred and ninety‐one (61.4%) patients were off the drug and 120 (38.6%) were on therapy during the pandemic. The relationship between drug discontinuation due to the COVID‐19 pandemic and recurrence was statistically significant (P < .001). Statistically significant relationships of age (P = .013) and treatment duration (P < .001) to recurrence were also found. The change in the SALT score differed between the patients on therapy and off therapy during the pandemic (P < .001). A significant negative correlation was found between the change in the SALT score and treatment duration: the spearman correlation test P = .018. We concluded that the patients may continue to the tofacitinib therapy during the rest of the COVID‐19 pandemic if the benefit outweighed the risk.

Off-label studies on ruxolitinib in dermatology: a review

Ruxolitinib is a Janus kinase (JAK) inhibitor that is FDA-approved for the treatment of myelofibrosis, polycythemia vera, and acute graft-versus-host disease. Its use in treating various dermatologic diseases has been a topic of growing interest due to its favorable safety profile and targeted inhibition of several cytokines that perpetuate inflammatory skin conditions. The PubMed/MEDLINE and ClinicalTrials.gov databases were searched for literature on off-label uses of ruxolitinib in dermatology and ongoing trials studying its safety and efficacy. There is randomized controlled trial (RCT) evidence for the successful use of ruxolitinib in treating alopecia, atopic dermatitis, and psoriasis, with ongoing RCTs for its use in vitiligo. Smaller studies have confirmed the success of ruxolitinib in treating conditions such as dermatomyositis and hypereosinophilic syndrome, among others. No serious adverse effects were reported with the use of ruxolitinib in dermatology, but further research is needed to determine its efficacy, delivery route, and optimal dosing for treating dermatologic conditions.

Emerging Topical and Systemic JAK Inhibitors in Dermatology

Accumulating data on cellular and molecular pathways help to develop novel therapeutic strategies in skin inflammation and autoimmunity. Examples are psoriasis and atopic dermatitis, two clinically and immunologically well-defined disorders. Here, the elucidation of key pathogenic factors such as IL-17A/IL-23 on the one hand and IL-4/IL-13 on the other hand profoundly changed our therapeutic practice. The knowledge on intracellular pathways and governing factors is shifting our attention to new druggable molecules. Multiple cytokine receptors signal through Janus kinases (JAKs) and associated signal transducer and activators of transcription (STATs). Inhibition of JAKs can simultaneously block the function of multiple cytokines. Therefore, JAK inhibitors (JAKi) are emerging as a new class of drugs, which in dermatology can either be used systemically as oral drugs or locally in topical formulations. Inhibition of JAKs has been shown to be effective in various skin disorders. The first oral JAKi have been recently approved for the treatment of rheumatoid arthritis and psoriatic arthritis. Currently, multiple inhibitors of the JAK/STAT pathway are being investigated for skin diseases like alopecia areata, atopic dermatitis, dermatomyositis, graft-versus-host-disease, hidradenitis suppurativa, lichen planus, lupus erythematosus, psoriasis, and vitiligo. Here, we aim to discuss the immunological basis and current stage of development of JAKi in dermatology.

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.