Dual Inhibition of TYK2 and JAK1 for the Treatment of Autoimmune Diseases: Discovery of (( S)-2,2-Difluorocyclopropyl)((1 R,5 S)-3-(2-((1-methyl-1 H-pyrazol-4-yl)amino)pyrimidin-4-yl)-3,8-diazabicyclo[3.2.1]octan-8-yl)methanone (PF-06700841)

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.

Comparative efficacy and safety of JAK inhibitors in the treatment of moderate-to-severe alopecia areata: a systematic review and network meta-analysis

We performed a Bayesian network meta-analysis to indirectly compare the relative efficacy and safety of the latest JAK inhibitors for moderate-to-severe alopecia areata (AA). 13 trials totaling 3,613 patients were included. Two low-dose groups of oral formulations (ritlecitinib 10mg and ivarmacitinib 2mg) and two topical formulations (delgocitinib ointment and ruxolitinib cream) appeared to be relatively ineffective against moderate-to-severe AA. Ranking analysis suggested that brepocitinib 30mg has the best relative effect in reducing the SALT score (sucra = 0.9831), and demonstrated comparable efficacy to deuruxolitinib 12mg (sucra = 0.9245), followed by deuruxolitinib 8mg (sucra = 0.7736). Regarding the SALT50 response, brepocitinib 30mg ranked highest (sucra = 0.9567), followed by ritlecitinib 50mg (sucra = 0.8689) and deuruxolitinib 12mg (sucra = 0.7690). For achieving the SALT75 response, deuruxolitinib 12mg had the highest probability (sucra = 0.9761), followed by deuruxolitinib 8mg (sucra = 0.8678) and brepocitinib 30mg (sucra = 0.8448). Deuruxolitinib 12mg might be the most effective therapy for patients with severe AA (sucra = 0.9395), followed by ritlecitinib 50mg (sucra = 0.8753) and deuruxolitinib 8mg (sucra = 0.8070). Deuruxolitinib 12mg/8mg demonstrated notable efficacy for moderate-to-severe AA, and is expected to be a new treatment option for AA. It was worth noting that deuruxolitinib exhibit a greater likelihood of causing adverse events in comparison to other JAK inhibitors. Ritlecitinib 50mg seemed to exhibit fewer adverse effects in the high-dose groups of oral JAK inhibitors and might be an optimal choice to balance safety and efficacy. The majority of JAK inhibitors exhibited acceptable short-term safety profiles. To enhance the applicability and accuracy of our research, further head-to-head trials with longer follow-up periods are needed. Systematic Review Registration: identifier [CRD42022368012].

Comprehensive overview of novel chemical drugs for ulcerative colitis: focusing on phase 3 and beyond

INTRODUCTION

Despite the growing number of highly efficacious biologics and chemical drugs for ulcerative colitis (UC), steroid-free disease control is still difficult to achieve in subgroups of patients due to refractoriness, adverse events, primary or secondary failure. New treatments are therefore still required in order to optimize clinical management of patients with UC.

AREAS COVERED

The efficacy and safety of both currently available and newly developed small molecules have been summarized. The PubMed database and clinicaltrials.gov were considered in order to search for phase 2b and 3 trials on new chemical drugs for UC. The study drugs reviewed included Janus kinases (JAK) and sphingosine-1-phosphate receptor (S1Pr) inhibitors, α4 integrin antagonist, and micro-RNA-124 upregulators.

EXPERT OPINION

Rapidity of onset, low immunogenicity, and safety are the main characteristics of small molecules currently available or under evaluation for treatment patients with UC. Among the currently available chemical drugs, the selective JAK and the S1Pr inhibitors are characterized by a good safety profile combined with the ability to induce clinical remission in UC. A relatively low frequency of endoscopic improvement and healing currently appears associated with their use, being higher in UC patients treated with S1Pr inhibitor Etrasimod. Overall, additional new safe and effective drugs are still required in order to optimize disease control in a larger majority of UC patients.

Community analysis of large-scale molecular dynamics simulations elucidated dynamics-driven allostery in tyrosine kinase 2

TYK2 is a nonreceptor tyrosine kinase, member of the Janus kinases (JAK), with a central role in several diseases, including cancer. The JAKs' catalytic domains (KD) are highly conserved, yet the isolated TYK2-KD exhibits unique specificities. In a previous work, using molecular dynamics (MD) simulations of a catalytically impaired TYK2-KD variant (P1104A) we found that this amino acid change of its JAK-characteristic insert (αFG), acts at the dynamics level. Given that structural dynamics is key to the allosteric activation of protein kinases, in this study we applied a long-scale MD simulation and investigated an active TYK2-KD form in the presence of adenosine 5'-triphosphate and one magnesium ion that represents a dynamic and crucial step of the catalytic cycle, in other protein kinases. Community analysis of the MD trajectory shed light, for the first time, on the dynamic profile and dynamics-driven allosteric communications within the TYK2-KD during activation and revealed that αFG and amino acids P1104, P1105, and I1112 in particular, hold a pivotal role and act synergistically with a dynamically coupled communication network of amino acids serving intra-KD signaling for allosteric regulation of TYK2 activity. Corroborating our findings, most of the identified amino acids are associated with cancer-related missense/splice-site mutations of the Tyk2 gene. We propose that the conformational dynamics at this step of the catalytic cycle, coordinated by αFG, underlie TYK2-unique substrate recognition and account for its distinct specificity. In total, this work adds to knowledge towards an in-depth understanding of TYK2 activation and may be valuable towards a rational design of allosteric TYK2-specific inhibitors.

Structure-guided design of potent JAK1-selective inhibitors based on 4-amino-7H-pyrrolo[2,3-d]pyrimidine with anti-inflammatory efficacy

In a continuous effort to develop Janus kinase 1 (JAK1)-selective inhibitors, a novel series of 4-amino-7H-pyrrolo[2,3-d]pyrimidine derivatives bearing the piperidinyl fragment were designed and synthesized according to a combination strategy. Through enzymatic assessments, the superior compound 12a with an IC50 value of 12.6 nM against JAK1 was identified and a 10.7-fold selectivity index over JAK2 was achieved. It was indicated that 12a displayed considerable effect in inhibiting the pro-inflammatory NO generated from lipopolysaccharide (LPS)-induced RAW264.7 macrophages, while on normal RAW264.7 cells, 12a exerted a weak cytotoxicity effect (IC50 = 143.3 μM). Furthermore, H&E stain assay demonstrated the conspicuous capacity of 12a to suppress CCl4-induced hepatic fibrosis levels in a dose-dependent manner in vivo. The binding model of 12a ideally reflects the excellent activity of JAK1 over the homologous kinase JAK2. Overall, 12a, a JAK1-selective inhibitor, exhibited potential for liver fibrosis and inflammatory diseases.

Small-molecule agents for treating skin diseases

Skin diseases are a class of common and frequently occurring diseases that significantly impact daily lives. Currently, the limited effective therapeutic drugs are far from meeting the clinical needs; most drugs typically only provide symptomatic relief rather than a cure. Developing small-molecule drugs with improved efficacy holds paramount importance for treating skin diseases. This review aimed to systematically introduce the pathogenesis of common skin diseases in daily life, list related drugs applied in the clinic, and summarize the clinical research status of candidate drugs and the latest research progress of candidate compounds in the drug discovery stage. Also, it statistically analyzed the number of publications and global attention trends for the involved skin diseases. This review might provide practical information for researchers engaged in dermatological drugs and further increase research attention to this disease area.

Design, synthesis and evaluation of C-5 substituted pyrrolopyridine derivatives as potent Janus Kinase 1 inhibitors with excellent selectivity

The development of highly selective Janus Kinase 1 (JAK1) inhibitors is crucial for improving efficacy and minimizing adverse effects in the clinical treatment of autoimmune diseases. In a prior study, we designed a series of C-5 4-pyrazol substituted pyrrolopyridine derivatives that demonstrated significant potency against JAK1, with a 10 ∼ 20-fold selectivity over Janus Kinase 2 (JAK2). Building on this foundation, we adopted orthogonal strategy by modifying the C-5 position with 3-pyrazol/4-pyrazol/3-pyrrol groups and tail with substituted benzyl groups on the pyrrolopyridine head to enhance both potency and selectivity. In this endeavor, we have identified several compounds that exhibit excellent potency and selectivity for JAK1. Notably, compounds 12b and 12e, which combined 4-pyrazol group at C-5 site and meta-substituted benzyl tails, displayed IC50 value with 2.4/2.2 nM and high 352-/253-fold selectivity for JAK1 over JAK2 in enzyme assays. Additionally, both compounds showed good JAK1-selective in Ba/F3-TEL-JAK1/2 cell-based assays. These findings mark a substantial improvement, as these compounds are 10-fold more potent and over 10-fold more selective than the best compound identified in our previous study. The noteworthy potency and selectivity properties of compounds 12b and 12e suggest their potential utility in furthering the development of drugs for autoimmune diseases.

Employing zero-inflated beta distribution in an exposure-response analysis of TYK2/JAK1 inhibitor brepocitinib in patients with plaque psoriasis

Brepocitinib is an oral selective dual TYK2/JAK1 inhibitor and based on its cytokine inhibition profile is expected to provide therapeutic benefit in the treatment of plaque psoriasis. Efficacy data from a completed Phase 2a study in patients with moderate-to-severe plaque psoriasis were utilized to develop a population exposure-response model that can be employed to inform dose selection decisions for further clinical development. A modeling approach that employs the zero-inflated beta distribution was used to account for the bounded nature and distributional characteristics of the Psoriasis Area and Severity Index (PASI) score data. The developed exposure-response model provided an adequate description of the observed PASI scores across all the treatment arms tested and across both the induction and maintenance dosing periods of the study. In addition, the developed model exhibited a good predictive capacity with regard to the derived responder metrics (e.g., 75%/90%/100% improvement in PASI score [PASI75/90/100]). Clinical trial simulations indicated that the induction/maintenance dosing paradigm explored in this study does not offer any advantages from an efficacy perspective and that doses of 10, 30, and 60 mg once-daily may be suitable candidates for clinical evaluation in subsequent Phase 2b studies.

Brepocitinib, Zimlovisertib, and Ropsacitinib in Hidradenitis Suppurativa

Kinase Inhibitors for Hidradenitis SuppurativaThree kinase inhibitor immunomodulators (daily oral brepocitinib, zimlovisertib, and ropsacitinib) were evaluated in this randomized, placebo-controlled trial of 194 patients with hidradenitis suppurativa. At 16 weeks, only brepocitinib, a JAK1/TYK2 inhibitor, achieved a higher clinical response than placebo (52% vs. 33%). The other two agents were no better than placebo.

Janus Kinase Inhibitor Brepocitinib Rescues Myelin Phagocytosis Under Inflammatory Conditions: In Vitro Evidence from Microglia and Macrophage Cell Lines

Central nervous system (CNS) injuries induce cell death and consequently the release of myelin and other cellular debris. Microglia as well as hematogenous macrophages actively collaborate to phagocyte them and undergo their degradation. However, myelin accumulation persists in the lesion site long after the injury with detrimental effects on axonal regeneration. This might be due to the presence of inhibitors of phagocytosis in the injury site. As we recently published that some proinflammatory stimuli, like interferon-γ (IFNγ) and lipopolysaccharide (LPS), inhibit myelin phagocytosis in macrophages, we have now studied the signaling pathways involved. A phagocytosis assay in Raw264.7 macrophages and N13 microglia cell lines with labeled myelin was developed with the pHrodo reagent that emits fluorescence in acidic cellular compartments (e.g.lysosomes). Pharmacological inhibition of Janus kinases (Jak) with Brepocitinib restored myelin phagocytosis and rescued the expression of genes related to phagocytosis, like triggering receptor expressed on myeloid cells 2 (TREM2), induced by IFNγ or LPS. In addition, while pharmacological inhibition of the signal transducer and activator of transcription 3 (STAT3) rescued myelin phagocytosis and the expression of phagocytosis related genes in the presence of LPS, it did not have any effect on IFNγ-treated cells. Our results show that Jak pathways participate in the inhibition of myelin phagocytosis by IFNγ and LPS. They also indicate that the resolution of inflammation is important for the clearance of cellular debris by macrophages and subsequent regenerative processes.

Therapeutic potential of a synthetic dual JAK1/TYK2 inhibitor in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic and incurable disease with an increasing incidence rate and low mortality rate. Selectively inhibiting JAK1 and TYK2 has been proposed as a strategy to enhance the efficacy of such inhibitors while minimizing the potential side effects on other JAK isoforms. Our previous studies identified small molecule 18 as a JAK1/TYK2 inhibitor with high selectivity and a new structure. Specifically, the IC50 of 18 at the kinase level reached 39 nM and 21 nM for JAK1 and TYK2, respectively, with 10-fold selectivity over both JAK2 and JAK3. In in vitro studies, 18 dose-dependently inhibited cytokine-induced STAT phosphorylation downstream of the JAK1 and TYK2 signaling pathway. In pharmacokinetic experiments, 18 demonstrated an oral bioavailability of 59.82%, making it a promising candidate for further in vivo studies. Using two mouse models of acute ulcerative colitis (UC) induced by the administration of dextran sulfate sodium (DSS) or oxazolone (OXA), 18 dose-dependently showed a better therapeutic effect than the positive control drug tofacitinib. Additionally, after long-term administration for 32 days, 18 displayed low toxicity to mice and a high safety profile. Taken together, these findings suggest that 18 is a JAK1/TYK2 dual inhibitor with therapeutic effects superior to those of tofacitinib in the treatment of IBD. Moreover, 18 is also a suitable clinical candidate for further investigation in diseases with strong involvement from interferon and/or IL-12/IL-23 in their pathogenesis. This study confirmed the therapeutic effect and long-term safety of inhibiting JAK1 and TYK2 to treat IBD.

Synthesis and clinical application of small-molecule inhibitors of Janus kinase

Janus kinase (JAK) plays a crucial role in intracellular signaling pathways, particularly in cytokine-mediated signal transduction, making them attractive therapeutic targets for a wide range of diseases, including autoimmune disorders, myeloproliferative neoplasms, and inflammatory conditions. The review provides a comprehensive overview of the development and therapeutic potential of small-molecule inhibitors targeting JAK family of proteins in various clinical trials. It also discusses the mechanisms of action, specificity, and selectivity of these inhibitors, shedding light on the challenges associated with achieving target selectivity while minimizing off-target effects. Moreover, the review offers insights into the clinical applications of JAK inhibitors, summarizing the ongoing clinical trials and the Food and Drug Administration (FDA)-approved JAK inhibitors currently available for various diseases. Overall, this review provides a thorough examination of the synthesis and clinical use of typical small-molecule JAK inhibitors in different clinical stages and offers a bright future for the development of novel small-molecule JAK inhibitors.

Recent advances in uveitis therapy: focus on selected phase 2 and 3 clinical trials

INTRODUCTION

Uveitis is a heterogeneous group of ocular conditions characterized by inflammation of the uveal tract. It is a leading cause of blindness in developed countries and exerts significant psychological, social, and economic impact on both patients and the larger society. While there are numerous pharmacotherapy options, posterior segment noninfectious uveitis remains a significant challenge to treat due to its severity, chronicity, and high recurrence rates.

AREAS COVERED

The index review highlights the unmet needs of uveitis pharmacotherapy and its research and the shortcomings of existing ocular and systemic therapeutic options for noninfectious uveitis. The more promising novel ocular drug delivery methods and therapeutic targets/drugs are discussed, and evidence from the clinical trials is evaluated.

EXPERT OPINION

There has been incredible growth in the number of treatment options available to uveitis patients today, especially with the new generation of biologic drugs. Available evidence suggests that these newer options may be superior to conventional immunosuppressive therapies in terms of efficacy and side effect profiles. Further high-quality research and additional clinical trials will be needed to clarify their roles in the stepladder treatment approach of noninfectious uveitis.

A gastrointestinal locally activating Janus kinase inhibitor to treat ulcerative colitis

In this study, we integrated machine learning (ML), structure-tissue selectivity-activity-relationship (STAR), and wet lab synthesis/testing to design a gastrointestinal (GI) locally activating JAK inhibitor for ulcerative colitis treatment. The JAK inhibitor achieves site-specific efficacy through high local GI tissue selectivity while minimizing the requirement for JAK isoform specificity to reduce systemic toxicity. We used the ML model (CoGT) to classify whether the designed compounds were inhibitors or noninhibitors. Then we used the regression ML model (MTATFP) to predict their IC50 against related JAK isoforms of predicted JAK inhibitors. The ML model predicted MMT3-72, which was retained in the GI tract, to be a weak JAK1 inhibitor, while MMT3-72-M2, which accumulated in only GI tissues, was predicted to be an inhibitor of JAK1/2 and TYK2. ML docking methods were applied to simulate their docking poses in JAK isoforms. Application of these ML models enabled us to limit our synthetic efforts to MMT3-72 and MMT3-72-M2 for subsequent wet lab testing. The kinase assay confirmed MMT3-72 weakly inhibited JAK1, and MMT3-72-M2 inhibited JAK1/2 and TYK2. We found that MMT3-72 accumulated in the GI lumen, but not in GI tissue or plasma, but released MMT3-72-M2 accumulated in colon tissue with minimal exposure in the plasma. MMT3-72 achieved superior efficacy and reduced p-STAT3 in DSS-induced colitis. Overall, the integration of ML, the structure-tissue selectivity-activity-relationship system, and wet lab synthesis/testing could minimize the effort in the optimization of a JAK inhibitor to treat colitis. This site-specific inhibitor reduces systemic toxicity by minimizing the need for JAK isoform specificity.

Kinase Signaling in Colitis-Associated Colon Cancer and Inflammatory Bowel Disease

Colorectal cancer is a known complication of chronic inflammation of the colon ("colitis-associated colon cancer"). Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract. Patients with IBD are at increased risk of colon cancer compared to the general population. Kinase signaling pathways play critical roles in both the inflammation and regulating cellular processes such as proliferation and survival that contribute to cancer development. Here we review the interplay of kinase signaling pathways (mitogen-activated protein kinases, cyclin-dependent kinases, autophagy-activated kinases, JAK-STAT, and other kinases) and their effects on colitis-associated colon cancer. We also discuss the role of JAK-STAT signaling in the pathogenesis of IBD and the therapeutic landscape of JAK inhibitors for the treatment of IBD.

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.

SOCS-JAK-STAT inhibitors and SOCS mimetics as treatment options for autoimmune uveitis, psoriasis, lupus, and autoimmune encephalitis

Autoimmune diseases arise from atypical immune responses that attack self-tissue epitopes, and their development is intricately connected to the disruption of the JAK-STAT signaling pathway, where SOCS proteins play crucial roles. Conditions such as autoimmune uveitis, psoriasis, lupus, and autoimmune encephalitis exhibit immune system dysfunctions associated with JAK-STAT signaling dysregulation. Emerging therapeutic strategies utilize JAK-STAT inhibitors and SOCS mimetics to modulate immune responses and alleviate autoimmune manifestations. Although more research and clinical studies are required to assess their effectiveness, safety profiles, and potential for personalized therapeutic approaches in autoimmune conditions, JAK-STAT inhibitors and SOCS mimetics show promise as potential treatment options. This review explores the action, effectiveness, safety profiles, and future prospects of JAK inhibitors and SOCS mimetics as therapeutic agents for psoriasis, autoimmune uveitis, systemic lupus erythematosus, and autoimmune encephalitis. The findings underscore the importance of investigating these targeted therapies to advance treatment options for individuals suffering from autoimmune diseases.

Targeting the Tyrosine Kinase 2 (TYK2) Pseudokinase Domain: Discovery of the Selective TYK2 Inhibitor ABBV-712

Tyrosine kinase 2 (TYK2) is a nonreceptor tyrosine kinase that belongs to the JAK family also comprising JAK1, JAK2, and JAK3. TYK2 is an attractive target for various autoimmune diseases as it regulates signal transduction downstream of IL-23 and IL-12 receptors. Selective TYK2 inhibition offers a differentiated clinical profile compared to currently approved JAK inhibitors. However, selectivity for TYK2 versus other JAK family members has been difficult to achieve with small molecules that inhibit the catalytically active kinase domain. Successful targeting of the TYK2 pseudokinase domain as a strategy to achieve isoform selectivity was recently exemplified with deucravacitinib. Described herein is the optimization of selective TYK2 inhibitors targeting the pseudokinase domain, resulting in the discovery of the clinical candidate ABBV-712 (21).

A phase 1 study to investigate the absorption, distribution, metabolism and excretion of brepocitinib in healthy males using a 14 C-microdose approach

AIMS

Brepocitinib is a tyrosine kinase 2/Janus kinase 1 inhibitor being investigated for the treatment of several autoimmune diseases. This study assessed the absorption, distribution, metabolism and excretion of oral brepocitinib, and the absolute oral bioavailability (F) and fraction absorbed (Fa ) using a 14 C microtracer approach.

METHODS

This was a phase 1 open-label, nonrandomized, fixed sequence, two-period, single-dose study of brepocitinib in healthy male participants. Participants received a single oral 60 mg dose of 14 C brepocitinib (~300 nCi) in Period A, then an unlabelled oral 60 mg dose followed by an intravenous (IV) 30 μg dose of 14 C labelled brepocitinib (~300 nCi) in Period B. Mass balance, pharmacokinetic parameters and safety were assessed.

RESULTS

Six participants were enrolled. Brepocitinib was absorbed rapidly following oral administration. In Period A, total recovery of the oral dose was 96.7% ± 6.3% (88.0% ± 8.0% in urine, 8.7% ± 2.1% in faeces). In Period B, a small fraction (6.0% of the oral dose) was recovered unchanged in urine. F and Fa were 74.6% (90% confidence interval 67.3%, 82.8%) and 106.9%, respectively. Brepocitinib demonstrated an acceptable safety profile and was well tolerated following oral or oral then IV administrations. No deaths, serious adverse events or discontinuations were reported.

CONCLUSION

Intestinal absorption of brepocitinib was essentially complete after oral administration, with F ~75%. Drug-related material recovery was high, with the majority excreted in urine. The major route of elimination of brepocitinib was renal excretion as metabolites, whereas urinary elimination of unchanged brepocitinib was minor. NCT: NCT03770039.

In Vitro and In Silico Investigation of BCI Anticancer Properties and Its Potential for Chemotherapy-Combined Treatments

BACKGROUND

DUSP6 phosphatase serves as a negative regulator of MAPK kinases involved in numerous cellular processes. BCI has been identified as a potential allosteric inhibitor with anticancer activity. Our study was designed to test the anticancer properties of BCI in colon cancer cells, to characterize the effect of this compound on chemotherapeutics such as irinotecan and oxaliplatin activity, and to identify potential molecular targets for this inhibitor.

METHODS

BCI cytotoxicity, proapoptotic activity, and cell cycle distribution were investigated in vitro on three colon cancer cell lines (DLD1, HT-29, and Caco-2). In silico investigation was prepared to assess BCI drug-likeness and identify potential molecular targets.

RESULTS

The exposure of colorectal cancer cells with BCI resulted in antitumor effects associated with cell cycle arrest and induction of apoptosis. BCI exhibited strong cytotoxicity on DLD1, HT-29, and Caco-2 cells. BCI showed no significant interaction with irinotecan, but strongly attenuated the anticancer activity of oxaliplatin when administered together. Analysis of synergy potential further confirmed the antagonistic interaction between these two compounds. In silico investigation indicated CDK5 as a potential new target of BCI.

CONCLUSIONS

Our studies point to the anticancer potential of BCI but note the need for a precise mechanism of action.

Therapeutic Effects of Upadacitinib on Experimental Autoimmune Uveitis: Insights From Single-Cell Analysis

Purpose

This study aimed to elucidate the impact of upadacitinib, a Janus kinase 1 (JAK1)-specific inhibitor, on experimental autoimmune uveitis (EAU) and explore its underlying mechanisms.

Methods

We utilized single-cell RNA sequencing (scRNA-seq) and single-cell assay for transposase-accessible chromatin sequencing (scATAC-seq) to investigate the JAK/signal transducer and activator of transcription (STAT) pathway in peripheral blood mononuclear cells (PBMCs) of 12 patients with Vogt-Koyanagi-Harada (VKH) disease and cervical draining lymph node (CDLN) cells of EAU. After treating EAU with upadacitinib, we analyzed immune cell gene expression and cell-cell communication by integrating scRNA data. Additionally, we applied flow cytometry and western blot to analyze the CDLN cells.

Results

The JAK/STAT pathway was found to be upregulated in patients with VKH disease and EAU. Upadacitinib effectively alleviated EAU symptoms, reduced JAK1 protein expression, and suppressed pathogenic CD4 T cell (CD4TC) proliferation and pathogenicity while promoting Treg proliferation. The inhibition of pathogenic CD4TCs by upadacitinib was observed in both flow cytometry and scRNA data. Additionally, upadacitinib was found to rescue the interferon-stimulated gene 15 (ISG15)+ CD4TCs and CD8 T and B cell ratios and reduce expression of inflammatory-related genes. Upadacitinib demonstrated the ability to inhibit abnormally activated cell-cell communication, particularly the CXCR4-mediated migration pathway, which has been implicated in EAU pathogenesis. CXCR4 inhibitors showed promising therapeutic effects in EAU.

Conclusions

Our findings indicate that the JAK1-mediated signaling pathway is significantly upregulated in uveitis, and upadacitinib exhibits therapeutic efficacy against EAU. Furthermore, targeting the CXCR4-mediated migration pathway could be a promising therapeutic strategy.

Oral Ritlecitinib and Brepocitinib for Moderate-to-Severe Ulcerative Colitis: Results From a Randomized, Phase 2b Study

BACKGROUND & AIMS

The efficacy and safety of ritlecitinib (oral JAK3/TEC family kinase inhibitor) and brepocitinib (oral TYK2/JAK1 inhibitor) as induction therapy were assessed in patients with active, moderate-to-severe ulcerative colitis.

METHODS

This phase 2b, parallel-arm, double-blind umbrella study randomized patients with moderate-to-severe ulcerative colitis to receive 8-week induction therapy with ritlecitinib (20, 70, 200 mg), brepocitinib (10, 30, 60 mg), or placebo once daily. The primary endpoint was total Mayo Score (TMS) at week 8.

RESULTS

Of 319 randomized patients, 317 received ritlecitinib (n = 150), brepocitinib (n = 142), or placebo (n = 25). The placebo-adjusted mean TMSs (90% confidence interval) at week 8 were -2.0 (-3.2 to -0.9), -3.9 (-5.0 to -2.7), and -4.6 (-5.8 to -3.5) for ritlecitinib 20, 70, and 200 mg, respectively (P = .003, P < .001, P < .001), and -1.8 (-2.9 to -0.7), -2.3 (-3.4 to -1.1), and -3.2 (-4.3 to -2.1) for brepocitinib 10, 30, and 60 mg, respectively (P = .009, P = .001, P < .001). Estimates (90% confidence interval) for placebo-adjusted proportions of patients with modified clinical remission at week 8 were 13.7% (0.5%-24.2%), 32.7% (20.2%-45.3%), and 36.0% (23.6%-48.6%) for ritlecitinib 20, 70, and 200 mg, respectively, and 14.6% (1.9%-25.7%), 25.5% (11.0%-38.1%), and 25.5% (11.0%-38.1%) for brepocitinib 10, 30, and 60 mg, respectively. Adverse events were mostly mild, and there were no serious cases of herpes zoster infection. Infections were observed with brepocitinib (16.9% [12.5%-23.7%]), ritlecitinib (8.7% [5.2%-13.4%]), and placebo (4.0% [0.2%-17.6%]). One death due to myocardial infarction (ritlecitinib) and 1 thromboembolic event (brepocitinib) occurred; both were considered unrelated to study drug.

CONCLUSIONS

Ritlecitinib and brepocitinib induction therapies were more effective than placebo for the treatment of moderate-to-severe active ulcerative colitis, with an acceptable short-term safety profile.

CLINICALTRIALS

gov number: NCT02958865.

Discovery of a Potent and Selective Tyrosine Kinase 2 Inhibitor: TAK-279

TYK2 is a key mediator of IL12, IL23, and type I interferon signaling, and these cytokines have been implicated in the pathogenesis of multiple inflammatory and autoimmune diseases such as psoriasis, rheumatoid arthritis, lupus, and inflammatory bowel diseases. Supported by compelling data from human genome-wide association studies and clinical results, TYK2 inhibition through small molecules is an attractive therapeutic strategy to treat these diseases. Herein, we report the discovery of a series of highly selective pseudokinase (Janus homology 2, JH2) domain inhibitors of TYK2 enzymatic activity. A computationally enabled design strategy, including the use of FEP+, was instrumental in identifying a pyrazolo-pyrimidine core. We highlight the utility of computational physics-based predictions used to optimize this series of molecules to identify the development candidate 30, a potent, exquisitely selective cellular TYK2 inhibitor that is currently in Phase 2 clinical trials for the treatment of psoriasis and psoriatic arthritis.

Recent progress on tyrosine kinase 2 JH2 inhibitors

Tyrosine kinase 2 (TYK2) is a member of the Janus kinase (JAK) family, which can regulate the signaling of multiple pro-inflammatory cytokines, including IL12, IL23 and type I interferon (IFNα/β), and its inhibitors can treat autoimmune diseases caused by the abnormal expression of IL12 and IL23. Interest in TYK2 JH2 inhibitors has increased as a result of safety concerns with JAK inhibitors. This overview introduces TYK2 JH2 inhibitors that are already on the market, including Deucravactinib (BMS-986165), as well as those currently in clinical trials, such as BMS-986202, NDI-034858, and ESK-001.

Eyes on Topical Ocular Disposition: The Considered Design of a Lead Janus Kinase (JAK) Inhibitor That Utilizes a Unique Azetidin-3-Amino Bridging Scaffold to Attenuate Off-Target Kinase Activity, While Driving Potency and Aqueous Solubility

An unmet medical need remains for patients suffering from dry eye disease (DED). A fast-acting, better-tolerated noncorticosteroid anti-inflammatory eye drop could improve patient outcomes and quality of life. Herein, we describe a small-molecule drug discovery effort to identify novel, potent, and water-soluble JAK inhibitors as immunomodulating agents for topical ocular disposition. A focused library of known 3-(4-(2-(arylamino)pyrimidin-4-yl)-1H-pyrazol-1-yl)propanenitriles was evaluated as a molecular starting point. Structure-activity relationships (SARs) revealed a ligand-efficient (LE) JAK inhibitor series, amenable to aqueous solubility. Subsequent in vitro analysis indicated the potential for off-target toxicity. A KINOMEscan selectivity profile of 5 substantiated the likelihood of widespread series affinity across the human kinome. An sp²-to-sp³ drug design strategy was undertaken to attenuate off-target kinase activity while driving JAK-STAT potency and aqueous solubility. Tactics to reduce aromatic character, increase fraction sp³ (Fsp³), and bolster molecular complexity led to the azetidin-3-amino bridging scaffold in 31.

An Analysis of Successful Hit-to-Clinical Candidate Pairs

An analysis of 156 published clinical candidates from the Journal of Medicinal Chemistry between 2018 and 2021 was conducted to identify lead generation strategies most frequently employed leading to drug candidates. As in a previous publication, the most frequent lead generation strategies resulting in clinical candidates were from known compounds (59%) followed by random screening approaches (21%). The remainder of the approaches included directed screening, fragment screening, DNA-encoded library screening (DEL), and virtual screening. An analysis of similarity was also conducted based on Tanimoto-MCS and revealed most clinical candidates were distant from their original hits; however, most shared a key pharmacophore that translated from hit-to-clinical candidate. An examination of frequency of oxygen, nitrogen, fluorine, chlorine, and sulfur incorporation in clinical candidates was also conducted. The three most similar and least similar hit-to-clinical pairs from random screening were examined to provide perspective on changes that occur that lead to successful clinical candidates.

Discovery of C-5 Pyrazole-Substituted Pyrrolopyridine Derivatives as Potent and Selective Inhibitors for Janus Kinase 1

Developing selective inhibitors for Janus kinase 1 (JAK1) is a significant focus for improving the efficacy and alleviating the adverse effects in treating immune-inflammatory diseases. Herein, we report the discovery of a series of C-5 pyrazole-modified pyrrolopyrimidine derivatives as JAK1-selective inhibitors. The potential hydrogen bond between the pyrazole group and E966 in JAK1 is the key point that enhances JAK1 selectivity. These compounds exhibit 10- to 20-fold JAK1 selectivity over JAK2 in enzyme assays. Compound 12b also exhibits excellent JAK1 selectivity in Ba/F3-TEL-JAK cellular assays. Metabolism studies and the results of the hair growth model in mice indicate that compound 12b may be a viable lead compound for the development of highly JAK1-selective inhibitors for immune and inflammatory diseases.

Identification of abemaciclib derivatives targeting cyclin-dependent kinase 4 and 6 using molecular dynamics, binding free energy calculation, synthesis, and pharmacological evaluation

CDK4/6 plays a crucial role in various cancers and is an effective anticancer drug target. However, the gap between clinical requirements and approved CDK4/6 drugs is unresolved. Thus, there is an urgent need to develop selective and oral CDK4/6 inhibitors, particularly for monotherapy. Here, we studied the interaction between abemaciclib and human CDK6 using molecular dynamics simulations, binding free energy calculations, and energy decomposition. V101 and H100 formed stable hydrogen bonds with the amine-pyrimidine group, and K43 interacted with the imidazole ring via an unstable hydrogen bond. Meanwhile, I19, V27, A41, and L152 interacted with abemaciclib through π-alkyl interactions. Based on the binding model, abemaciclib was divided into four regions. With one region modification, 43 compounds were designed and evaluated using molecular docking. From each region, three favorable groups were selected and combined with each other to obtain 81 compounds. Among them, C2231-A, which was obtained by removing the methylene group from C2231, showed better inhibition than C2231. Kinase profiling revealed that C2231-A showed inhibitory activity similar to that of abemaciclib; additionally, C2231-A inhibited the growth of MDA-MB-231 cells to a greater extent than did abemaciclib. Based on molecular dynamics simulation, C2231-A was identified as a promising candidate compound with considerable inhibitory effects on human breast cancer cell lines.

Chronic pruritus: from pathophysiology to drug design

Pruritus, the most common symptom in dermatology, is an innate response capable of protecting skin against irritants. Nonetheless, when it lasts more than six weeks it is assumed to be a chronic pathology having a negative impact on people's lives. Chronic pruritus (CP) can occur in common and rare skin diseases, having a high prevalence in global population. The existing therapies are unable to counteract CP or are associated with adverse effects, so the development of effective treatments is a pressing issue. The pathophysiological mechanisms underlying CP are not yet completely dissected but, based on current knowledge, involve a wide range of receptors, namely neurokinin 1 receptor (NK1R), Janus kinase (JAK), and transient receptor potential (TRP) ion channels, especially transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1). This review will address the relevance of these molecular targets for the treatment of CP and molecules capable of modulating these receptors that have already been studied clinically or have the potential to possibly alleviate this pathology. According to scientific and clinical literature, there is an increase in the expression of these molecular targets in the lesioned skin of patients experiencing CP when compared with non-lesioned skin, highlighting their importance for the development of potential efficacious drugs through the design of antagonists/inhibitors.

Hederagenin ameliorates renal fibrosis in chronic kidney disease through blocking ISG15 regulated JAK/STAT signaling

Interstitial fibrosis is the key pathological characteristics of chronic kidney diseases (CKD). In this study, we reported that hederagenin (HDG) can effectively improve the renal interstitial fibrosis and its mechanism. We constructed CKD animal models of ischemia reperfusion injury (IRI) and unilateral ureteral obstruction (UUO) respectively to observe the improvement effect of HDG on CKD. The results showed that HDG can effectively improve the pathological structure of kidney and the renal fibrosis in CKD mice. Meanwhile, HDG can also significantly reduce the expression of α-SMA and FN induced by TGF-β in Transformed C3H Mouse Kidney-1 (TCMK1) cells. Mechanistically, we performed transcriptome sequencing on UUO kidneys treated with HDG. By real time PCR screening of the sequencing results, we determined that ISG15 plays an important role in the intervention of HDG in CKD. Subsequently, we knocked-down ISG15 in TCMK1 and found that ISG15 knock-down significantly inhibited TGF-β-induced fibrotic protein expression and JAK/STAT activation. Finally, we performed electrotransfection and used liposomes to transfect ISG15 overexpression plasmids to up-regulate ISG15 in kidney and cells, respectively. We found that ISG15 can aggravate renal tubular cell fibrosis and abolish the protection of HDG on CKD. These results indicated that HDG significantly improves renal fibrosis in CKD by inhibiting ISG15 and its downstream JAK/STAT signaling pathway, which provides a new drug and research target for the subsequent treatment of CKD.

Selective JAK1 inhibitors for the treatment of inflammatory bowel disease

Janus kinase (JAK) inhibitors, also known as jakinibs, are third-generation oral small molecules that have expanded the therapeutic options for the management of chronic inflammatory diseases, including inflammatory bowel disease (IBD). Tofacitinib, a pan-JAK inhibitor, has spearheaded the new JAK class for IBD treatment. Unfortunately, serious adverse effects, including cardiovascular complications such as pulmonary embolism and venous thromboembolism or even death from any cause, have been reported for tofacitinib. However, it is anticipated that next-generation selective JAK inhibitors may limit the development of serious adverse events, leading to a safer treatment course with these novel targeted therapies. Nevertheless, although this drug class was recently introduced, following the launch of second-generation biologics in the late 1990s, it is breaking new ground and has been shown to efficiently modulate complex cytokine-driven inflammation in both preclinical models and human studies. Herein, we review the clinical opportunities for targeting JAK1 signaling in the pathophysiology of IBD, the biology and chemistry underpinning these target-selective compounds, and their mechanisms of actions. We also discuss the potential for these inhibitors in efforts to balance their benefits and harms.

Tyk2 Targeting in Immune-Mediated Inflammatory Diseases

The Janus kinase (Jak)/signal transducer and activating protein (STAT) pathways mediate the intracellular signaling of cytokines in a wide spectrum of cellular processes. They participate in physiologic and inflammatory cascades and have become a major focus of research, yielding novel therapies for immune-mediated inflammatory diseases (IMID). Genetic linkage has related dysfunction of Tyrosine kinase 2 (Tyk2)-the first member of the Jak family that was described-to protection from psoriasis. Furthermore, Tyk2 dysfunction has been related to IMID prevention, without increasing the risk of serious infections; thus, Tyk2 inhibition has been established as a promising therapeutic target, with multiple Tyk2 inhibitors under development. Most of them are orthosteric inhibitors, impeding adenosine triphosphate (ATP) binding to the JH1 catalytic domain-which is highly conserved across tyrosine kinases-and are not completely selective. Deucravacitinib is an allosteric inhibitor that binds to the pseudokinase JH2 (regulatory) domain of Tyk2; this unique mechanism determines greater selectivity and a reduced risk of adverse events. In September 2022, deucravacitinib became the first Tyk2 inhibitor approved for the treatment of moderate-to-severe psoriasis. A bright future can be expected for Tyk2 inhibitors, with newer drugs and more indications to come.

Novel Therapies in Plaque Psoriasis: A Review of Tyrosine Kinase 2 Inhibitors

Plaque psoriasis is a systemic immune-mediated disease driven by interleukin-17 producing cells under the regulation of interleukin-23. Interleukin-23 signaling is mediated by the intracellular kinase tyrosine kinase 2, a Janus kinase family member. Tyrosine kinase 2 is a potential target for oral small-molecule therapies to treat psoriasis and psoriatic arthritis. A number of tyrosine kinase 2 inhibitors are in development or approved for the treatment of psoriasis or psoriatic arthritis. Deucravacitinib, an oral, selective, allosteric tyrosine kinase 2 inhibitor, is approved by the US Food and Drug Administration as a first-in-class treatment for adults with moderate-to-severe plaque psoriasis who are candidates for systemic therapy or phototherapy, and is approved by Pharmaceuticals and Medical Devices Agency (PDMA) in Japan for patients with plaque psoriasis, generalized pustular psoriasis, and erythrodermic psoriasis who have had an inadequate response to conventional therapies. Deucravacitinib selectively binds to the unique tyrosine kinase 2 regulatory pseudokinase domain in an allosteric fashion, preventing a conformational change in the catalytic domain required for ATP substrate binding, thus effectively locking tyrosine kinase 2 in an inactive state. Two other tyrosine kinase 2 inhibitors in later stage clinical development, brepocitinib (PF-06700841) and ropsacitinib (PF-06826647), are orthosteric inhibitors that target the highly conserved catalytic domain. This selective allosteric tyrosine kinase 2 inhibition may explain the improved safety profile of deucravacitinib versus orthosteric Janus kinase and tyrosine kinase 2 inhibitors. Two phase 3 psoriasis trials demonstrated deucravacitinib was efficacious and not associated with safety concerns characteristic of Janus kinase inhibitors, hence the new class designation (TYK2 inhibitor) by health authorities in the USA and Japan. Allosteric tyrosine kinase 2 inhibitors represent a promising new class of molecules for the treatment of psoriasis and psoriatic arthritis, and longer-term trials will establish their place in therapy.

JAK inhibitors: A new dawn for oral therapies in inflammatory bowel diseases

Inflammatory bowel disease (IBD) is a chronic immune-mediated condition of the gastrointestinal tract that requires chronic treatment and strict surveillance. Development of new monoclonal antibodies targeting one or a few single cytokines, including anti-tumor necrosis factor agents, anti-IL 12/23 inhibitors, and anti-α4β7 integrin inhibitors, have dominated the pharmacological armamentarium in IBD in the last 20 years. Still, many patients experience incomplete or loss of response or develop serious adverse events and drug discontinuation. Janus kinase (JAK) is key to modulating the signal transduction pathway of several proinflammatory cytokines directly involved in gastrointestinal inflammation and, thus, probably IBD pathogenesis. Targeting the JAK-STAT pathway offers excellent potential for the treatment of IBD. The European Medical Agency has approved three JAK inhibitors for treating adults with moderate to severe Ulcerative Colitis when other treatments, including biological agents, have failed or no longer work or if the patient cannot take them. Although there are currently no approved JAK inhibitors for Crohn's disease, upadacitinib and filgotinib have shown increased remission rates in these patients. Other JAK inhibitors, including gut-selective molecules, are currently being studied IBD. This review will discuss the JAK-STAT pathway, its implication in the pathogenesis of IBD, and the most recent evidence from clinical trials regarding the use of JAK inhibitors and their safety in IBD patients.

Identification of TUL01101: A Novel Potent and Selective JAK1 Inhibitor for the Treatment of Rheumatoid Arthritis

Janus kinase 1 (JAK1) is a potential target for the treatment of rheumatoid arthritis (RA). In this study, the introduction of a spiro ring with a difluoro-substituted cyclopropionamide resulted in the identification of TUL01101 (compound 36) based on a triazolo[1,5-a]pyridine core of filgotinib. It showed excellent potency on JAK1 with an IC₅₀ value of 3 nM and exhibited more than 12-fold selectivity for JAK2 and TYK2. Whole blood assay also demonstrated the high activity and selectivity (37-fold for JAK2). At the same time, TUL01101 also demonstrated excellent metabolic stability and pharmacokinetics (PK) profiles were assayed in three species (mouse, rat, and dog). Moreover, it has been validated for effective activity in the treatment of RA both in collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA) models, with low dose and low toxicity. Now, TUL01101 has progressed into phase I clinical trials.

Novel therapies in axial spondyloarthritis

Over the past two decades, advancements in understanding the pathogenesis of axial spondyloarthritis have led to discoveries of new therapeutic targets, particularly the interleukin-17, tumor necrosis factor axis, and Janus kinase-signal transducer and activator of transcription pathway. While many of the available agents have proven to be efficacious and safe for the treatment of axial spondyloarthritis, a remarkable percentage of patients either fail or cannot tolerate these medications. This has prompted researchers to look for new targets that would maximize efficacy and minimize toxicity. In this article, we review novel agents that were recently approved, in trials, and possible future targets or mechanisms. We also discuss their role as it pertains to the prevention of radiographic progression and the management of extra-musculoskeletal manifestations.

Population Pharmacokinetics of Oral Brepocitinib in Healthy Volunteers and Patients

Brepocitinib is a tyrosine kinase 2 and Janus kinase 1 inhibitor in development for treatment of inflammatory autoimmune diseases. This analysis aimed to add to the pharmacokinetic knowledge of the medication, through development of a population pharmacokinetic model and identification of factors that affect drug disposition. Plasma samples from 5 clinical trials were collated, composed of healthy volunteers, patients with psoriasis and patients with alopecia areata taking oral brepocitinib. NONMEM was used to develop a population pharmacokinetic model, and patient demographics were tested as covariates. The final model was a 1-compartment model with first-order absorption. The typical values for apparent clearance and apparent volume of distribution were 18.7 L/h (78% coefficient of variation [CV]) and 136 L (60.5% CV), respectively. Absorption was rapid with an absorption constant of 3.46 h, with an absorption lag of 0.24 hours observed with the oral tablet formulation. The proportional residual error was found to be 52.7% CV in healthy volunteers and 87.5% CV in patients. High-fat meals were associated with a reduction in both the rate (69.9% lower) and extent (28.3% lower) of absorption, while Asian populations had reduced clearance (24.3% lower). Nonlinear pharmacokinetics were observed at doses of 175 mg and above, with a 35.1% higher relative bioavailability at these doses. There were insufficient data to describe this nonlinearity as a continuous relationship. This initial description of the population pharmacokinetics will act as a foundation for the model-informed drug development of brepocitinib and will facilitate future modeling of this medicine. ClinicalTrials.gov numbers NCT02310750 NCT03236493 NCT03656952 NCT02969018 NCT02974868.

Type 1 interferon suppresses expression and glucocorticoid induction of glucocorticoid-induced leucine zipper (GILZ)

SLE is a systemic multi-organ autoimmune condition associated with reduced life expectancy and quality of life. Glucocorticoids (GC) are heavily relied on for SLE treatment but are associated with detrimental metabolic effects. Type 1 interferons (IFN) are central to SLE pathogenesis and may confer GC insensitivity. Glucocorticoid-induced leucine zipper (GILZ) mediates many effects of GC relevant to SLE pathogenesis, but the effect of IFN on GC regulation of GILZ is unknown. We performed in vitro experiments using human PBMC to examine the effect of IFN on GILZ expression. JAK inhibitors tofacitinib and tosylate salt were used in vivo and in vitro respectively to investigate JAK-STAT pathway dependence of our observations. ChiP was performed to examine glucocorticoid receptor (GR) binding at the GILZ locus. Several public data sets were mined for correlating clinical data. High IFN was associated with suppressed GILZ and reduced GILZ relevant to GC exposure in a large SLE population. IFN directly reduced GILZ expression and suppressed the induction of GILZ by GC in vitro in human leukocytes. IFN actions on GILZ expression were dependent on the JAK1/Tyk2 pathway, as evidenced by loss of the inhibitory effect of IFN on GILZ in the presence of JAK inhibitors. Activation of this pathway led to reduced GR binding in key regulatory regions of the GILZ locus. IFN directly suppresses GILZ expression and GILZ upregulation by GC, indicating a potential mechanism for IFN-induced GC resistance. This work has important implications for the ongoing development of targeted GC-sparing therapeutics in SLE.

Novel TYK2 Inhibitors with an N-(Methyl-d 3)pyridazine-3-carboxamide Skeleton for the Treatment of Autoimmune Diseases

Tyrosine kinase 2 (TYK2) mediates the interleukin-23 (IL-23), IL-12, and type I interferon (IFN)-driven signal responses that are critical in autoimmune diseases. Here, a series of novel derivatives with an N-(methyl-d 3)pyridazine-3-carboxamide skeleton that bind to the TYK2 pseudokinase domain were designed, synthesized, and evaluated. Among them, compound 30 demonstrated more excellent inhibitory potency against STAT3 phosphorylation than the positive control deucravacitinib. In addition to JAK isoform selectivity, compound 30 exhibited good in vivo and in vitro pharmacokinetic properties. Furthermore, compound 30 was orally highly effective in both IL-23-driven acanthosis and anti-CD40-induced colitis models. Together, these findings support compound 30 as a promising candidate for therapeutic applications in autoimmune diseases.

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.

Enantioselective Formation of All-Carbon Quaternary Stereocenters in gem-Difluorinated Cyclopropanes via Rhodium-Catalyzed Stereoablative Kinetic Resolution

Herein, we report an effective method to offer chiral gem-difluorinated cyclopropanes containing an all-carbon quaternary stereocenter by rhodium-catalyzed stereoablative kinetic resolution. The activation of a sterically hindered all-carbon quaternary C-C bond through oxidative addition with a chiral rhodium complex is proposed as the enantiodetermining step. A wide range of gem-difluorinated cyclopropanes can be obtained with excellent ee values (ee = 87% to >99.9%), which are demonstrated to be useful chiral fluorine-containing building blocks by a series of postfunctionalizations.

Multitargeting the Action of 5-HT6 Serotonin Receptor Ligands by Additional Modulation of Kinases in the Search for a New Therapy for Alzheimer's Disease: Can It Work from a Molecular Point of View?

In view of the unsatisfactory treatment of cognitive disorders, in particular Alzheimer’s disease (AD), the aim of this review was to perform a computer-aided analysis of the state of the art that will help in the search for innovative polypharmacology-based therapeutic approaches to fight against AD. Apart from 20-year unrenewed cholinesterase- or NMDA-based AD therapy, the hope of effectively treating Alzheimer’s disease has been placed on serotonin 5-HT₆ receptor (5-HT₆R), due to its proven, both for agonists and antagonists, beneficial procognitive effects in animal models; however, research into this treatment has so far not been successfully translated to human patients. Recent lines of evidence strongly emphasize the role of kinases, in particular microtubule affinity-regulating kinase 4 (MARK4), Rho-associated coiled-coil-containing protein kinase I/II (ROCKI/II) and cyclin-dependent kinase 5 (CDK5) in the etiology of AD, pointing to the therapeutic potential of their inhibitors not only against the symptoms, but also the causes of this disease. Thus, finding a drug that acts simultaneously on both 5-HT₆R and one of those kinases will provide a potential breakthrough in AD treatment. The pharmacophore- and docking-based comprehensive literature analysis performed herein serves to answer the question of whether the design of these kind of dual agents is possible, and the conclusions turned out to be highly promising.

Study of Novel Furocoumarin Derivatives on Anti-Vitiligo Activity, Molecular Docking and Mechanism of Action

Vitiligo is a common chronic dermatological abnormality that afflicts tens of millions of people. Furocoumarins isolated from Uygur traditional medicinal material Psoralen corylifolia L. have been proven to be highly effective for the treatment of vitiligo. Although many furocoumarin derivatives with anti-vitiligo activity have been synthesized, their targets with respect to the disease are still ambiguous. Fortunately, the JAKs were identified as potential targets for the disease and its inhibitors have been proved to be effective in the treatment of vitiligo in many clinical trials. Thus, sixty-five benzene sulfonate and benzoate derivatives of furocoumarins (7a–7ad, 8a–8ag) with superior anti-vitiligo activity targeting JAKs were designed and synthesized based on preliminary research. The SAR was characterized after the anti-vitiligo-activity evaluation in B16 cells. Twenty-two derivatives showed more potent effects on melanin synthesis in B16 cells than the positive control (8-MOP). Among them, compounds 7y and 8 not only could increase melanin content, but they also improved the catecholase activity of tyrosinase in a concentration-dependent manner. The docking studies indicated that they were able to interact with amino acid residues in JAK1 and JAK2 via hydrogen bonds. Furthermore, candidate 8 showed a moderate inhibition of CXCL−10, which plays an important role in JAK–STAT signaling. The RT-PCR and Western blotting analyses illustrated that compounds 7y and 8 promoted melanogenesis by activating the p38 MAPK and Akt/GSK-3β/β-catenin pathways, as well as increasing the expressions of the MITF and tyrosinase-family genes. Finally, furocoumarin derivative 8 was recognized as a promising candidate for the fight against the disease and worthy of further research in vivo.

Potent and selective TYK2-JH1 inhibitors highly efficacious in rodent model of psoriasis

TYK2 is a member of the JAK family of kinases and a key mediator of IL-12, IL-23, and type I interferon signaling. These cytokines have been implicated in the pathogenesis of multiple inflammatory and autoimmune diseases such as psoriasis, rheumatoid arthritis, lupus, and inflammatory bowel diseases. Supported by compelling data from human genetic association studies, TYK2 inhibition is an attractive therapeutic strategy for these diseases. Herein, we report the discovery of a series of highly selective catalytic site TYK2 inhibitors designed using FEP+ and structurally enabled design starting from a virtual screen hit. We highlight the structure-based optimization to identify a lead candidate 30, a potent cellular TYK2 inhibitor with excellent selectivity, pharmacokinetic properties, and in vivo efficacy in a mouse psoriasis model.

Interleukin-23 in the Pathogenesis of Inflammatory Bowel Disease and Implications for Therapeutic Intervention

The interleukin-23 [IL-23] cytokine, derived predominantly from macrophages and dendritic cells in response to microbial stimulation, has emerged as a critical promoter of chronic intestinal inflammation. Genome-wide association studies linking variants in IL23R to disease protection, bolstered by experimental evidence from colitis models, and the successful application of therapies against the IL-12/IL-23 shared p40 subunit in the treatment of inflammatory bowel disease [IBD] all provide compelling evidence of a crucial role for IL-23 in disease pathogenesis. Moreover, targeting the p19 subunit specific for IL-23 has shown considerable promise in recent phase 2 studies in IBD. The relative importance of the diverse immunological pathways downstream of IL-23 in propagating mucosal inflammation in the gut, however, remains contentious. Here we review current understanding of IL-23 biology and explore its pleiotropic effects on T cells, and innate lymphoid, myeloid and intestinal epithelial cells in the context of the pathogenesis of IBD. We furthermore discuss these pathways in the light of recent evidence from clinical trials and indicate emerging targets amenable to therapeutic intervention and translation into clinical practice.

The Potential Role of Phenolic Acids from Salvia miltiorrhiza and Cynara scolymus and Their Derivatives as JAK Inhibitors: An In Silico Study

JAK inhibition is a new strategy for treating autoimmune and inflammatory diseases. Previous studies have shown the immunoregulatory and anti-inflammatory effects of Salvia miltiorrhiza and Cynara scolymus and suggest that the bioactivity of their phenolic acids involves the JAK-STAT pathway, but it is unclear whether these effects occur through JAK inhibition. The JAK binding affinities obtained by docking Rosmarinic acid (RosA), Salvianolic acid A (SalA), Salvianolic acid C (SalC), Lithospermic acid, Salvianolic acid B and Cynarin (CY) to JAK (PDB: 6DBN) with AutoDock Vina are −8.8, −9.8, −10.7, −10.0, −10.3 and −9.7 kcal/mol, respectively. Their predicted configurations enable hydrogen bonding with the hinge region and N- and C-terminal lobes of the JAK kinase domain. The benzofuran core of SalC, the compound with the greatest binding affinity, sits near Leu959, such as Tofacitinib’s pyrrolopyrimidine. A SalC derivative with a binding affinity of −12.2 kcal/mol was designed while maintaining this relationship. The docking results show follow-up studies of these phenolic acids as JAK inhibitors may be indicated. Furthermore, derivatives of SalC, RosA, CY and SalA can yield better binding affinity or bioavailability scores, indicating that their structures may be suitable as scaffolds for the design of new JAK inhibitors.

Selective tyrosine kinase 2 inhibitors in inflammatory bowel disease

Recent significant advances have been made in the treatment of chronic inflammatory diseases with initiation of the era of biologics. However, an unmet medical need still exists for novel targeted therapies. Compared with biologics, Janus kinase inhibitors (JAKis) are a new drug class of orally administered small molecules that have been shown to efficiently modulate complex cytokine-driven inflammation in preclinical models and human studies. Unfortunately, serious adverse effects have been reported with the first introduced pan-JAKi, tofacitinib. Here, we review tyrosine kinase 2 (TYK2) signaling in the pathophysiology of inflammatory bowel disease (IBD), examine mechanisms of action of selective TYK2 inhibitors (TYK2is), and discuss the potential for these inhibitors in efforts to balance benefits and harms.

Targeting Janus Kinase (JAK) for Fighting Diseases: The Research of JAK Inhibitor Drugs

Janus Kinase (JAK), a nonreceptor protein tyrosine kinase, has emerged as an excellent target through research and development since its discovery in the 1990s. As novel small-molecule targeted drugs, JAK inhibitor drugs have been successfully used in the treatment of rheumatoid arthritis (RA), myofibrosis (MF) and ulcerative colitis (UC). With the gradual development of JAK targets in the market, JAK inhibitors have also received very considerable feedback in the treatment of autoimmune diseases such as atopic dermatitis (AD), Crohn's disease (CD) and graft-versus host disease (GVHD). This article reviews the research progress of JAK inhibitor drugs: introducing the existing JAK inhibitors on the market and some JAK inhibitors in clinical trials currently. In addition, the synthesis of various types of JAK inhibitors were summarized, and the effects of different drug structures on drug inhibition and selectivity.