Improvement of cutaneous inflammation and panniculitis in dermatomyositis patients by the JAK-inhibitor baricitinib

Current evidence for janus kinase inhibitors in adult and juvenile dermatomyositis and key comparisons

INTRODUCTION

Adult dermatomyositis (DM) and juvenile dermatomyositis (JDM) are rare autoimmune diseases with characteristic skin rashes, weakness, and other systemic features. Upregulated interferon signaling has been consistently described in both adult and juvenile DM which makes janus kinase inhibitors (jakinibs) an attractive therapeutic agent that has a targeted mechanism of action.

AREAS COVERED

Herein is a review of the growing literature of jakinib use in adult and juvenile DM, including reports on specific disease features and safety of jakinibs in this population and a comparison between adult and juvenile DM. We performed a literature review using PubMed including all English-language publications before 1 February 2024 and abstracts from key recent rheumatology conferences.

EXPERT OPINION

Jakinibs are an exciting and promising treatment in both adult and juvenile DM. Current Phase 2 and 3 randomized placebo-controlled trials of jakinibs in both adult and JDM will provide significant insights into the efficacy of this class of medication as a potentially more mechanistically targeted treatment of both skin and muscle disease. In fact, these results will likely inform the treatment paradigm of dermatomyositis in that it may even be considered as first or second line. The next five years in the therapeutic landscape of both juvenile and adult DM is an exciting time for both patients and medical providers.

A rare case of symptomatic creatine kinase elevation in a patient with rheumatoid arthritis treated with baricitinib

The safety profile of baricitinib (BARI), a Janus kinase inhibitor broadly used for the treatment of rheumatoid arthritis (RA), includes asymptomatic laboratory abnormalities, such as an increase in creatine kinase (CK). Data from randomized controlled trials suggest that concomitant myalgia is rare in RA and does not lead to drug discontinuation. We describe the case of a 68-year-old Caucasian female with longstanding, multi-failure RA who started BARI and achieved disease remission. However, she developed a symptomatic CK increase, as well as a parallel increase in total cholesterol, low-density lipoprotein, and triglycerides. Dechallenge-rechallenge demonstrated a plausible relationship between the clinical/laboratory abnormalities and BARI. In fact, when the drug was withdrawn, CK returned to normal and myalgia disappeared, whereas symptoms returned and CK levels increased when BARI was restarted. BARI may be rarely associated with symptomatic CK elevation, and this may pose clinical challenges, particularly for patients with multi-failure RA who achieved good disease control with BARI but required drug discontinuation due to intolerance.

Ruxolitinib for Refractory PL-12 Antisynthetase Syndrome-Associated Angioedema-Like Panniculitis With Clonal T-Cell Receptor Gene Rearrangement

This case report describes a woman in her 30s who presented with a 3-year history of anti–PL-12 antisynthetase syndrome characterized by interstitial lung disease, arthritis, and myositis and was diagnosed with antisynthetase syndrome–associated panniculitis.

[Current update on dermatomyositis]

Dermatomyositis (DM) is a rare autoimmune disease with involvement of skin and muscle that is classified as an idiopathic inflammatory myopathy. In addition to cutaneous lesions as well as weakness and atrophy of muscles, the heart and lungs are the major affected organs. DM occurs in association with malignant tumors in 20% of affected adults. The pathogenesis of the disease is not completely understood. DM is a multifactorial disease influenced by genetic, environmental and immunological factors. The immune response is characterized by activation of innate and adaptive immune mechanisms and a strong activation of the type I interferon pathway. Myositis-specific antibodies are characteristic of DM and allow differential diagnosis. Therapies include corticosteroids, antimalarials, immunoglobulins, biologics such as rituximab or JAK inhibitors. Early diagnosis and treatment are essential for the prognosis.

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.

Leveraging Genomic and Bioinformatic Analysis to Enhance Drug Repositioning for Dermatomyositis

Dermatomyositis (DM) is an autoimmune disease that is classified as a type of idiopathic inflammatory myopathy, which affects human skin and muscles. The most common clinical symptoms of DM are muscle weakness, rash, and scaly skin. There is currently no cure for DM. Genetic factors are known to play a pivotal role in DM progression, but few have utilized this information geared toward drug discovery for the disease. Here, we exploited genomic variation associated with DM and integrated this with genomic and bioinformatic analyses to discover new drug candidates. We first integrated genome-wide association study (GWAS) and phenome-wide association study (PheWAS) catalogs to identify disease-associated genomic variants. Biological risk genes for DM were prioritized using strict functional annotations, further identifying candidate drug targets based on druggable genes from databases. Overall, we analyzed 1239 variants associated with DM and obtained 43 drugs that overlapped with 13 target genes (JAK2, FCGR3B, CD4, CD3D, LCK, CD2, CD3E, FCGR3A, CD3G, IFNAR1, CD247, JAK1, IFNAR2). Six drugs clinically investigated for DM, as well as eight drugs under pre-clinical investigation, are candidate drugs that could be repositioned for DM. Further studies are necessary to validate potential biomarkers for novel DM therapeutics from our findings.

Targeting intracellular pathways in idiopathic inflammatory myopathies: A narrative review

In recent decades, several pieces of evidence have drawn greater attention to the topic of innate immunity, in particular, interferon (IFN) and Interleukin 6 in the pathogenesis of idiopathic inflammatory myopathies (IIM). Both of these molecules transduce their signal through a receptor coupled with Janus kinases (JAK)/signal transducer and activator of transcription proteins (STAT). In this review, we discuss the role of the JAK/STAT pathway in IIM, evaluate a possible therapeutic role for JAK inhibitors in this group of diseases, focusing on those with the strongest IFN signature (dermatomyositis and antisynthetase syndrome).

Update on dermatomyositis

PURPOSE OF REVIEW

This review summarizes and comments on current knowledge in dermatomyositis.

RECENT FINDINGS

The 2018 European Neuromuscular Centre classification of dermatomyositis has been challenging by the discovery of clinicopathological features associated with dermatomyositis-specific antibody (DMSA) that were not incorporated in the original criteria. These features include but may not be limited to the presence of perifascicular necrosis in anti-Mi-2 dermatomyositis; presence of diffuse nonperifascicular sarcoplasmic myxovirus resistance protein A expression in anti-MDA5 dermatomyositis; and dermatomyositis sine dermatitis in anti-NXP-2 dermatomyositis. Variations and subclassifications within the same DMSA subtypes are observed: anti-MDA5 dermatomyositis is clinically subcategorized into good, intermediate, and poor prognostic subgroups; concurrent anti-CCAR1 and anti-TIF1-γ positivity identify anti-TIF1-γ-positive patient with a lower risk for cancer-associated myositis. Owing to distinct IFN1-signaling pathway activation in dermatomyositis, JAK-STAT inhibitor - the pathway-targeted therapy, have been studied with promising results in refractory dermatomyositis and some new-onset dermatomyositis. In addition, the potential serum biomarkers for IFN1 pathway activation are being investigated for their performance in monitoring the disease activity and the efficacy of the treatment.

SUMMARY

DMSA, evidence of prominent IFN1 pathway activation, and risk/severity-associated biomarkers would likely play major roles in future dermatomyositis classification, disease monitoring, and treatment decision.

Advancements in the Treatment of Cutaneous Lupus Erythematosus and Dermatomyositis: A Review of the Literature

Background

Cutaneous lupus erythematosus (CLE) and dermatomyositis (DM) are autoimmune diseases that present with a wide variety of cutaneous manifestations. In both cases, first-line therapy includes topical corticosteroids. Patients may present with more widespread disease requiring systemic treatments, including corticosteroids, traditional immunosuppressants, or antimalarials. Due to their complex nature, both CLE and DM remain difficult to treat and continue to cause significant distress to patients.

Objective

To summarize the most recent literature on the safety and efficacy of novel treatment modalities for CLE and DM.

Methods

A literature search was conducted on PubMed using search terms “(dermatomyositis) AND (treatment)” and “(cutaneous lupus) AND (treatment)”. Additional search terms included specific names of biologic agents, phosphodiesterase inhibitors (apremilast), and JAK inhibitors.

Results

JAK inhibitors, PDE-4 inhibitors, and biologics have shown promise in reducing cutaneous symptoms of both CLE and DM, including reduction in SLE Disease Activity Index 2000 (SLEDAI-2K), Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI), British Isles Lupus Assessment Group (BILAG), Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI), and Disease Activity Score (DAS).

Conclusion

While there have been recent advancements in the treatment for CLE and DM, further research and clinical trials are required to better elucidate which therapy is best for individual patients.

JAK1/2 Inhibitor Baricitinib Improves Skin Fibrosis and Digital Ulcers in Systemic Sclerosis

Background

Systemic sclerosis (SSc) is a rare disabling connective tissue disease with few available treatment options. Diffuse cutaneous systemic sclerosis (dcSSc) is associated with high mortality. A previous experiment has shown that JAK2 inhibitor can significantly improve skin fibrosis in bleomycin (BLM)-induced murine model, including reducing dermal thickening and collagen accumulation. We aimed to describe the efficacy of oral JAK1/2 inhibitor baricitinib in SSc patients, especially focusing on skin fibrosis and microvascular manifestations.

Methods

We described the different effects of oral selective JAK1, JAK2, or JAK3 inhibitor treatment in a BLM-induced skin fibrosis mouse model. Furthermore, 10 adult patients with dcSSc were treated with baricitinib. We assessed the changes in modified rodman skin score (mRSS) and digital ulcer net burden at week 12 and 24 from baseline. We also compared the absolute changes in scores on the Scleroderma Health Assessment Questionnaire (SHAQ) and a total score on the St. George's Respiratory Questionnaire (SGRQ) over a 24-week period.

Results

In the experimental mouse model of skin fibrosis, a JAK1 and JAK2 inhibitor ameliorated skin fibrosis, and a JAK2 inhibitor had the most obvious effect. Treatment with the JAK2 inhibitor also blunted the capillary rarefaction. We demonstrated that skin fibrosis and digital ulcers were significantly relieved in 10 SSc patients treated with baricitinib. The mRSS significantly improved at week 12 from baseline, with a mean change in mRSS of -8.3 [95% confidence interval (CI), -12.03 to -4.574; p = 0.0007] and improved greater at week 24 to -11.67 (95% CI, -16.84 to -6.496; p = 0.0008). Among the four patients with digital ulcers (DU), three were completely healed at week 24, the number of ulcers in another patient was significantly reduced, and there was no patient with new ulcers. Only one adverse event (AE) of herpes zoster was observed.

Conclusions

Our results indicate that selective JAK1 and JAK2 inhibitor alleviates skin fibrosis, and oral JAK1/2 inhibitor baricitinib is a potentially effective treatment for dcSSc patients with skin fibrosis and DU. Baricitinib was well-tolerated by most patients in this study. Additional large clinical trials are needed to confirm our pilot findings.

Chinese Clinical Trial Registry Number

ChiCTR2000030995.