JAK inhibitor tofacitinib for treating rheumatoid arthritis: from basic to clinical

Time to talk to adults with rheumatic diseases about herpes zoster vaccination

The 2019 European Alliance of Associations for Rheumatology (EULAR) recommendations on herpes zoster vaccination for adult patients with rheumatic immune-mediated inflammatory diseases stated that these patients are at increased risk of herpes zoster compared with the general population. However, these recommendations lack clarity and specificity and are cautiously phrased, which might cause physicians to underestimate the importance of herpes zoster vaccination for these patients, potentially resulting in suboptimal protection. Since the formulation of the 2019 EULAR guidelines, new data on herpes zoster in patients with immune-mediated inflammatory diseases have been published. Moreover, a recombinant herpes zoster vaccine (Shingrix) has become available that can be given to these patients in a more accessible manner than the original live-attenuated vaccine (Zostavax). Here, we evaluate existing evidence on risk factors for herpes zoster and the safety and efficacy of the recombinant vaccine in patients with rheumatic immune-mediated inflammatory diseases and discuss the necessity of herpes zoster vaccination for these patients.

Drug Retention Rates of Janus Kinase Inhibitors in Rheumatoid Arthritis Patients with Therapy-Induced Lymphopenia

OBJECTIVES

To determine whether drug-induced lymphocytopenia is associated with drug retention rates of JAKi (tofacitinib or baricitinib) in rheumatoid arthritis (RA) patients.

METHODS

Patients with RA who were initiated with tofacitinib (n = 38) or baricitinib (n = 74) between July 2015 and July 2022 and continued for at least 4 months were enrolled in this study. Absolute lymphocyte count (ALC) value was obtained pre-treatment and monthly after initiation of JAKi (up to 4 months). Associations between ALC nadir at an early phase (up to 4 months) from JAKi initiation and drug retention rates were analysed.

RESULTS

112 patients (87 females; age, 71.2 ± 14.0 years; disease duration, 9.2 ± 10.5 months; DAS28-CRP, 3.60 ± 1.12; DAS28-ESR, 4.43 ± 1.29; CDAI, 17.9 ± 12.9; C-reactive protein, 3.07 ± 3.43 mg/dL; and lymphocyte count, 1361.9 ± 538.7 per μL) treated with tofacitinib or baricitinib were retrospectively analysed. Lymphocytopenia (>10% decline in lymphocyte count to pre-treatment basal levels) was observed in a quarter of RA patients treated with JAKi (tofacitinib; 16 baricitinib; 14). RA patients with lymphopenia were associated with the lower drug retention rates of tofacitinib compared to those without lymphocytopenia. The reduced drug retention rates in patients with lymphocytopenia were attributed to the discontinuation of tofacitinib due to AEs. Whereas lymphocytopenia was not associated with lower drug retention rates of baricitinib. Pre-treatment absolute lymphocyte counts did not affect the drug retention rates of JAKi in patients with RA.

CONCLUSIONS

These findings suggest that lymphopenia during the first 4 months from the initiation of JAKi is associated with reduced drug retention rates in patients with RA due to AEs, which is exclusively associated with the use of tofacitinib.

Metabolic reprogramming in Rheumatoid Arthritis Synovial Fibroblasts: A hybrid modeling approach

Rheumatoid Arthritis (RA) is an autoimmune disease characterized by a highly invasive pannus formation consisting mainly of Synovial Fibroblasts (RASFs). This pannus leads to cartilage, bone, and soft tissue destruction in the affected joint. RASFs' activation is associated with metabolic alterations resulting from dysregulation of extracellular signals' transduction and gene regulation. Deciphering the intricate mechanisms at the origin of this metabolic reprogramming may provide significant insight into RASFs' involvement in RA's pathogenesis and offer new therapeutic strategies. Qualitative and quantitative dynamic modeling can address some of these features, but hybrid models represent a real asset in their ability to span multiple layers of biological machinery. This work presents the first hybrid RASF model: the combination of a cell-specific qualitative regulatory network with a global metabolic network. The automated framework for hybrid modeling exploits the regulatory network's trap-spaces as additional constraints on the metabolic network. Subsequent flux balance analysis allows assessment of RASFs' regulatory outcomes' impact on their metabolic flux distribution. The hybrid RASF model reproduces the experimentally observed metabolic reprogramming induced by signaling and gene regulation in RASFs. Simulations also enable further hypotheses on the potential reverse Warburg effect in RA. RASFs may undergo metabolic reprogramming to turn into "metabolic factories", producing high levels of energy-rich fuels and nutrients for neighboring demanding cells through the crucial role of HIF1.

Metabolic Profiling of Rheumatoid Arthritis Neutrophils Reveals Altered Energy Metabolism That Is Not Affected by JAK Inhibition

Neutrophils play a key role in the pathophysiology of rheumatoid arthritis (RA) where release of ROS and proteases directly causes damage to joints and tissues. Neutrophil function can be modulated by Janus Kinase (JAK) inhibitor drugs, including tofacitinib and baricitinib, which are clinically effective treatments for RA. However, clinical trials have reported increased infection rates and transient neutropenia during therapy. The subtle differences in the mode of action, efficacy and safety of JAK inhibitors have been the primary research topic of many clinical trials and systematic reviews, to provide a more precise and targeted treatment to patients. The aim of this study was to determine both the differences in the metabolome of neutrophils from healthy controls and people with RA, and the effect of different JAK inhibitors on the metabolome of healthy and RA neutrophils. Isolated neutrophils from healthy controls (HC) (n = 6) and people with RA (n = 7) were incubated with baricitinib, tofacitinib or a pan-JAK inhibitor (all 200 ng/mL) for 2 h. Metabolites were extracted, and 1H nuclear magnetic resonance (NMR) was applied to study the metabolic changes. Multivariate analyses and machine learning models showed a divergent metabolic pattern in RA neutrophils compared to HC at 0 h (F1 score = 86.7%) driven by energy metabolites (ATP, ADP, GTP and glucose). No difference was observed in the neutrophil metabolome when treated with JAK inhibitors. However, JAK inhibitors significantly inhibited ROS production and baricitinib decreased NET production (p < 0.05). Bacterial killing was not impaired by JAK inhibitors, indicating that the effect of JAK inhibitors on neutrophils can inhibit joint damage in RA without impairing host defence. This study highlights altered energy metabolism in RA neutrophils which may explain the cause of their dysregulation in inflammatory disease.

Impact of the HLA-DRB1 shared epitope on responses to treatment with tofacitinib or abatacept in patients with rheumatoid arthritis

Objectives

The aim of this study was to compare the clinical effectiveness of tofacitinib and abatacept and clarify the impact of the HLA-DRB1 shared epitope (SE) on responses to these treatments in patients with rheumatoid arthritis (RA).

Methods

After adjustments by propensity score matching, 70 out of 161 patients receiving tofacitinib and 70 out of 131 receiving abatacept were extracted. The clinical effectiveness of both drugs over 24 weeks and the impact of the copy numbers of SE on effectiveness outcomes were investigated.

Results

The percentage of patients in remission in the 28-joint count disease activity score using the erythrocyte sedimentation rate (DAS28-ESR) did not significantly differ between patients receiving tofacitinib and abatacept at week 24 (32% vs 37%, p = 0.359). The mean change at week 4 in DAS28-ESR from baseline was significantly greater in patients receiving tofacitinib than in those receiving abatacept (− 1.516 vs − 0.827, p = 0.0003). The percentage of patients in remission at week 4 was 30% with tofacitinib and 15% with abatacept (p = 0.016). When patients were stratified by the copy numbers of SE alleles, differences in these numbers did not affect DAS28-ESR scores of patients receiving tofacitinib. However, among patients receiving abatacept, DAS28-ESR scores were significantly lower in patients carrying 2 copies of SE alleles than in those carrying 0 copies at each time point throughout the 24-week period. Furthermore, the percentage of patients in remission with DAS28-ESR at week 24 was not affected by the copy numbers of SE alleles in patients receiving tofacitinib (p = 0.947), whereas it significantly increased as the copy numbers became higher in patients receiving abatacept (p = 0.00309). Multivariable logistic regression analyses showed a correlation between the presence of SE and DAS28-ESR remission in patients receiving abatacept (OR = 25.881, 95% CI = 3.140–213.351, p = 0.0025), but not in those receiving tofacitinib (OR = 1.473, 95% CI = 0.291–7.446, p = 0.639).

Conclusions

Although the clinical effectiveness of tofacitinib and abatacept was similar at week 24, tofacitinib was superior to abatacept for changes from baseline in DAS28-ESR and the achievement of remission at week 4. SE positivity was associated with the achievement of DAS28-ESR remission by week 24 in patients receiving abatacept, but not in those receiving tofacitinib.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02612-w.

Effect of hepcidin antagonists on anemia during inflammatory disorders

Iron is an essential element for the mammalian body however, its homeostasis must be regulated accurately for appropriate physiological functioning. Alterations in physiological iron levels can lead to moderate to severe iron disorders like chronic and acute iron deficiency (anemia) or iron overload. Hepcidin plays an important role in regulating homeostasis between circulating iron and stored iron in the cells as well as the absorption of dietary iron in the intestine. Inflammatory disorders restrict iron absorption from food due to increased circulating levels of hepcidin. Increased production of hepcidin causes ubiquitination of ferroportin (FPN) leading to its degradation, thereby retaining iron in the spleen, duodenal enterocytes, macrophages, and hepatocytes. Hepcidin inhibitors and antagonists play a consequential role to ameliorate inflammation-associated anemia. Many natural and synthesized compounds, able to reduce hepcidin expression during inflammation have been identified in recent years. Few of which are currently at various phases of clinical trial. This article comprises a comprehensive review of therapeutic approaches for the efficient treatment of anemia associated with inflammation. Many strategies have been developed targeting the hepcidin-FPN axis to rectify iron disorders. Hepcidin modulation with siRNAs, antibodies, chemical compounds, and plant extracts provides new insights for developing advanced therapeutics for iron-related disorders. Hepcidin antagonist's treatment has a high potential to improve iron status in patients with iron disorders, but their clinical success needs further recognition along with the identification and application of new therapeutic approaches.

Sitagliptin and tofacitinib ameliorate adjuvant induced arthritis via modulating the cross talk between JAK/STAT and TLR-4/NF-κB signaling pathways

AIMS

Rheumatoid arthritis is an autoimmune systemic disorder causing pain, swelling, stiffness, and disability in various joints. This work was designed to evaluate the effect of sitagliptin and tofacitinib on Janus kinase (JAK)/signaling transducer and activator of transcription (STAT) and toll like receptor (TLR-4)/nuclear factor kappa B (NF-κB) signaling pathways in adjuvant induced arthritis in rats.

MATERIALS AND METHODS

Severity of arthritis was evaluated and serum was analyzed for inflammatory mediators. The mRNA and protein expression level of the most important members of the two signaling pathways were determined. Lipid profile, transaminases and renal function parameters were assessed.

KEY FINDINGS

Sitagliptin and tofacitinib significantly decreased the level of inflammatory parameters, the mRNA and protein expression level of the members of JAK/STAT and TLR-4/NF-κB pathways with more prominent effect of sitagliptin on TLR-4/NF-κB pathway and more expected obvious effect of tofacitinib on JAK/STAT pathway. The combination offered additional anti-inflammatory effect by inhibiting the cross talk between these pathways as inhibition of NF-κB activation decreased the serum level of IL-6 preventing the activation of STAT-3 in tibiotarsal tissues.

SIGNIFICANCE

The combination of tofacitinib and sitagliptin normalized serum lipids and blood glucose level which could offer protection against cardiovascular diseases and caused partial reversal of serum transaminases and creatinine levels which can protect against tofacitinb's related hepato and nephrotoxicity. We could conclude that the combination of Sitagliptin with tofacitinib can offer synergistic anti-inflammatory effect and more protective action against side effects of tofacitinib.

The Effect of JAK Inhibitor on the Survival, Anagen Re-Entry, and Hair Follicle Immune Privilege Restoration in Human Dermal Papilla Cells

Topical or systemic administration of JAK inhibitors has been shown to be a new treatment modality for severe alopecia areata (AA). Some patients show a good response to JAK inhibitors, but frequently relapse after cessation of the treatment. There have been no guidelines about the indications and use of JAK inhibitors in treating AA. The basic pathomechanism of AA and the relevant role of JAK inhibitors should support how to efficiently use JAK inhibitors. We sought to investigate the effect of JAK1/2 inhibitor on an in vitro model of AA and to examine the possible mechanisms. We used interferon gamma-pretreated human dermal papilla cells (hDPCs) as an in vitro model of AA. Ruxolitinib was administered to the hDPCs, and cell viability was assessed. The change of expression of the Wnt/β-catenin pathway, molecules related to the JAK-STAT pathway, and growth factors in ruxolitinib-treated hDPCs was also examined by reverse transcription PCR and Western blot assay. We examined immune-privilege-related molecules by immunohistochemistry in hair-follicle culture models. Ruxolitinib did not affect the cell viability of the hDPCs. Ruxolitinib activated several molecules in the Wnt/β-catenin signaling pathway, including Lef1 and β-catenin, and suppressed the transcription of DKK1 in hDPCs, but not its translation. Ruxolitinib reverted IFN-γ-induced expression of caspase-1, IL-1β, IL-15, and IL-18, and stimulated several growth factors, such as FGF7. Ruxolitinib suppressed the phosphorylation of JAK1, JAK2 and JAK3, and STAT1 and 3 compared to IFN-γ pretreated hDPCs. Ruxolitinib pretreatment showed a protective effect on IFN-γ-induced expression of MHC-class II molecules in cultured hair follicles. In conclusion, ruxolitinib modulated and reverted the interferon-induced inflammatory changes by blocking the JAK-STAT pathway in hDPCs under an AA-like environment. Ruxolitinib directly stimulated anagen-re-entry signals in hDPCs by affecting the Wnt/β-catenin pathway and promoting growth factors in hDPCs. Ruxolitinib treatment prevented IFN-γ-induced collapse of hair-follicle immune privilege.

A case of rheumatoid arthritis with multiple lung rheumatoid nodules successfully treated with tofacitinib

Sporadic cases of rheumatoid nodules (RNs) in the lung during treatment with tumour necrosis factor (TNF) inhibitors have been reported, but no treatment has been established. Here, we report a case of symptomatic lung RNs refractory to abatacept (ABT) and intravenous cyclophosphamide (IVCY) that improved with tofacitinib (TOF) treatment. A 75-year-old Japanese woman with a 10-year history of rheumatoid arthritis (RA) presented with a cough and haemoptysis during treatment with etanercept (ETN). Radiographic examinations revealed multiple nodules that were diagnosed as lung RNs via biopsy. The ETN was discontinued and ABT followed by IVCY was introduced; however, neither was sufficiently effective against the lung RNs. Thereafter, TOF was started and the lung RNs improved rapidly. The precise mechanisms that induce RNs during treatment with TNF inhibitors are unknown. Cytokines (IL-23 and IL-6) are suspected to be involved. TOF may be a reasonable strategy for treating symptomatic lung RNs.

Tofacitinib modulates the VZV-specific CD4+ T cell immune response in vitro in lymphocytes of patients with rheumatoid arthritis

OBJECTIVE

RA is a chronic inflammatory disease characterized by lymphocyte infiltration and release of inflammatory cytokines. Previous studies have shown that treatment with Janus kinase inhibitors, such as tofacitinib, increased the incidence rate of herpes zoster compared with conventional DMARDs. Therefore, this study aimed to investigate the effect of tofacitinib on the varicella-zoster-virus (VZV)-specific T cell immune response.

METHODS

The effect of tofacitinib on the VZV-specific T cell immune response was determined by evaluating the IFNγ production, the proliferative capacity, the VZV-induced differentiation into effector and memory T cells, the expression of activation marker CD69 and helper T cell type 1 (Th1)-characteristic chemokine receptors, such as CXCR3 and CCR5, as well as cytotoxic activity (perforin and granzyme B expression) of CD4+ T cells of patients with RA compared with healthy donors upon stimulation with VZV antigen in vitro.

RESULTS

Tofacitinib significantly reduced the IFNγ production, proliferation, activation, and CXCR3 expression of VZV-specific CD4+ T cells in a dose-dependent manner in short- and long-term lymphocyte culture. No effect on the distribution of naive, effectors or memory, or on the expression of perforin or granzyme B by VZV-specific CD4+ T cells was observed.

CONCLUSION

This study showed that tofacitinib significantly modulated the Th1 response to VZV. The poor VZV-specific cellular immune response in patients with RA may be considered in recommendations regarding appropriate vaccination strategies for enhancing the VZV-specific Th1 response.

B cell checkpoints in autoimmune rheumatic diseases

B cells have important functions in the pathogenesis of autoimmune diseases, including autoimmune rheumatic diseases. In addition to producing autoantibodies, B cells contribute to autoimmunity by serving as professional antigen-presenting cells (APCs), producing cytokines, and through additional mechanisms. B cell activation and effector functions are regulated by immune checkpoints, including both activating and inhibitory checkpoint receptors that contribute to the regulation of B cell tolerance, activation, antigen presentation, T cell help, class switching, antibody production and cytokine production. The various activating checkpoint receptors include B cell activating receptors that engage with cognate receptors on T cells or other cells, as well as Toll-like receptors that can provide dual stimulation to B cells via co-engagement with the B cell receptor. Furthermore, various inhibitory checkpoint receptors, including B cell inhibitory receptors, have important functions in regulating B cell development, activation and effector functions. Therapeutically targeting B cell checkpoints represents a promising strategy for the treatment of a variety of autoimmune rheumatic diseases.

Efficacy and safety of peficitinib (ASP015K) in patients with rheumatoid arthritis and an inadequate response to methotrexate: results of a phase III randomised, double-blind, placebo-controlled trial (RAJ4) in Japan

Objective

To evaluate the efficacy and safety of the oral Janus kinase (JAK) inhibitor peficitinib versus placebo in Japanese patients with rheumatoid arthritis (RA).

Methods

In this multicentre, double-blind, parallel-group, placebo-controlled phase III study, patients with RA and inadequate response to methotrexate (MTX) were randomised 1:1:1 to placebo, peficitinib 100 mg once daily or peficitinib 150 mg once daily with MTX for 52 weeks. Based on baseline randomisation, at week 12, non-responders receiving placebo were switched to peficitinib until the end of treatment; the remaining patients were switched to peficitinib at week 28. Primary efficacy variables were American College of Rheumatology (ACR)20 response rate at week 12/early termination (ET) and change from baseline in van der Heijde-modified total Sharp score (mTSS) at week 28/ET.

Results

519 patients were randomised and treated. Significantly more (p<0.001) peficitinib (58.6%, 100 mg; 64.4%, 150 mg) than placebo (21.8%) recipients achieved ACR20 response at week 12/ET. Significantly lower (p<0.001) mean changes from baseline in mTSS at week 28/ET occurred in peficitinib (1.62, 100 mg; 1.03, 150 mg) than placebo (3.37) recipients. Peficitinib was associated with haematological and biochemical parameter changes, and increased incidence of serious infections and herpes zoster-related disease. One death from suicide occurred in a patient in the placebo group after switching to peficitinib 100 mg.

Conclusions

In Japanese patients with RA and inadequate response to MTX, peficitinib demonstrated significant superiority versus placebo in reducing RA symptoms and suppressing joint destruction. Peficitinib had an acceptable safety and tolerability profile, with no new safety signals compared with other JAK inhibitors.

Trial registration number

NCT02305849.

Design, synthesis and anti-inflammatory evaluation of novel pyrrolo[2,3-d]pyrimidin derivatives as potent JAK inhibitors

Aiming to develop potent JAK inhibitors, two series of 4-(1H-pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidine derivatives (8a-8p and 11a-11i) were designed and synthesized by coalescing various N-acylpiperidine motifs with baricitinib. The pharmacological results based on enzymatic and cellular assays identified the optimized compound 11e, which exerted over 90% inhibition rates against JAK1 and JAK2, and displayed the most compelling anti-inflammatory efficacy superior to baricitinib by inhibiting NO generation from LPS-induced RAW264.7 macrophages. Importantly, low cytotoxity of 11e was revealed by the IC₅₀ value of 88.2 μM against normal RAW264.7 cells. The binding mode of 11e with JAK1 and JAK2 identified the essential structural bases in accord with SARs analysis. Furthermore, cellular morphology observation and western blot analysis disclosed the ability of 11e to relieve cells inflammatory damage by significantly down-regulating LPS-induced high expression of JAK1, JAK2, as well as pro cytokine IL-1β. Together, 11e was verified as a promising lead for JAK inhibitors for the treatment of inflammatory diseases.

Xanthatin inhibits STAT3 and NF-κB signalling by covalently binding to JAK and IKK kinases

Aberrant activation of the signal transducer and activator of transcription 3 (STAT3) and the nuclear factor‐κB (NF‐κB) signalling pathways is associated with the development of cancer and inflammatory diseases. JAKs and IKKs are the key regulators in the STAT3 and NF‐κB signalling respectively. Therefore, the two families of kinases have been the major targets for developing drugs to regulate the two signalling pathways. Here, we report a natural compound xanthatin from the traditional Chinese medicinal herb Xanthium L. as a potent inhibitor of both STAT3 and NF‐κB signalling pathways. Our data demonstrated that xanthatin was a covalent inhibitor and its activities depended on its α‐methylene‐γ‐butyrolactone group. It preferentially interacted with the Cys243 of JAK2 and the Cys412 and Cys464 of IKKβ to inactivate their activities. In doing so, xanthatin preferentially inhibited the growth of cancer cell lines that have constitutively activated STAT3 and p65. These data suggest that xanthatin may be a promising anticancer and anti‐inflammation drug candidate.

Inhibition of MMPs and ADAM/ADAMTS

Matrix metalloproteinases (MMPs), A Disintegrin and Metalloproteinase (ADAM) and A Disintegrin and Metalloproteinase with Thrombospondin Motif (ADAMTS) are zinc-dependent endopeptidases that play a critical role in the destruction of extracellular matrix proteins and, the shedding of membrane-bound receptor molecules in various forms of arthritis and other diseases. Under normal conditions, MMP, ADAM and ADAMTS gene expression aids in the maintenance of homeostasis. However, in inflamed synovial joints characteristic of rheumatoid arthritis and osteoarthritis. MMP, ADAM and ADAMTS production is greatly increased under the influence of pro-inflammatory cytokines. Analyses based on medicinal chemistry strategies designed to directly inhibit the activity of MMPs have been largely unsuccessful when these MMP inhibitors were employed in animal models of rheumatoid arthritis and osteoarthritis. This is despite the fact that these MMP inhibitors were largely able to suppress pro-inflammatory cytokine-induced MMP production in vitro. A focus on ADAM and ADAMTS inhibitors has also been pursued. Thus, recent progress has identified the "sheddase" activity of ADAMs as a viable target and the development of GW280264X is an experimental ADAM17 inhibitor. Of note, a monoclonal antibody, GLPG1972, developed as an ADAMTS-5 inhibitor, entered a Phase I OA clinical trial. However, the failure of many of these previously developed inhibitors to move beyond the preclinical testing phase has required that novel strategies be developed that are designed to suppress both MMP, ADAM and ADAMTS production and activity.

Minimum Infliximab Dosage for Keeping Serum Infliximab Levels Greater than 1 µg/mL among Patients with Rheumatoid Arthritis

Infliximab shows drastic efficacy for controlling inflammation in rheumatoid arthritis (RA), though the ideal dose of infliximab to keep suppressing inflammation has not yet been identified. Recently, it has been evidenced that the minimum trough serum infliximab levels required for suppressing inflammation are greater than 1 µg/mL. This cross-sectional study was designed to identify the minimum dosage of infliximab for maintaining serum infliximab levels greater than 1 µg/mL. Thirty seven RA patients were enrolled in this study and they were divided into two groups (high-infliximab vs. low-infliximab) in reference to Remi-check Q^®, a kit for examining serum infliximab levels above/below 1 µg/mL by LC. Infliximab dosage (p=0.06) and dosage interval (p=0.05) had trends to have differences between groups. A formula calculated by infliximab dosage divided by dosage interval and body weight (mg/weeks/kg) was shown to have significantly higher levels among high-infliximab group (p=0.04). Based on whether serum infliximab levels above/below 1 µg/mL and values led by the equation, infliximab dosage/infliximab interval/body weight (mg/weeks/kg), a receiver operating characteristic curve (ROC) was depicted with area under the ROC curve 0.750 and the cut-off point for the serum infliximab levels greater than 1 µg/mL was identified as infliximab dosage/infliximab interval/body weight ≧0.750 with the sensitivity 0.393 and the specificity 1.000. In conclusion, we identified that the minimum infliximab dosage to maintain serum infliximab levels greater than 1 µg/mL was infliximab dose/dosage interval/body weight (mg/weeks/kg)≥0.750.

SPACIA1/SAAL1 Deletion Results in a Moderate Delay in Collagen-Induced Arthritis Activity, along with mRNA Decay of Cyclin-dependent Kinase 6 Gene

This study was performed to elucidate the molecular function of the synoviocyte proliferation-associated in collagen-induced arthritis (CIA) 1/serum amyloid A-like 1 (SPACIA1/SAAL1) in mice CIA, an animal model of rheumatoid arthritis (RA), and human RA-synovial fibroblasts (RASFs). SPACIA1/SAAL1-deficient mice were generated and used to create mouse models of CIA in mild or severe disease conditions. Cell cycle-related genes, whose expression levels were affected by SPACIA1/SAAL1 small interfering RNA (siRNA), were screened. Transcriptional and post-transcriptional effects of SPACIA1/SAAL1 siRNA on cyclin-dependent kinase (cdk) 6 gene expression were investigated in human RASFs. SPACIA1/SAAL1-deficient mice showed later onset and slower progression of CIA than wild-type mice in severe disease conditions, but not in mild conditions. Expression levels of cdk6, but not cdk4, which are D-type cyclin partners, were downregulated by SPACIA1/SAAL1 siRNA at the post-transcriptional level. The exacerbation of CIA depends on SPACIA1/SAAL1 expression, although CIA also progresses slowly in the absence of SPACIA1/SAAL1. The CDK6, expression of which is up-regulated by the SPACIA1/SAAL1 expression, might be a critical factor in the exacerbation of CIA.

Effects of tofacitinib in early arthritis-induced bone loss in an adjuvant-induced arthritis rat model

Objectives

The main goal of this work was to analyse how treatment intervention with tofacitinib prevents the early disturbances of bone structure and mechanics in the rat model of adjuvant-induced arthritis. This is the first study to access the impact of tofacitinib on the skeletal bone effects of inflammation.

Methods

Fifty Wistar rats with adjuvant-induced arthritis were randomly housed in experimental groups, as follows: non-arthritic healthy group (n = 20); arthritic non-treated group (n = 20); and 10 animals undergoing tofacitinib treatment. Rats were monitored during 22 days after disease induction for the inflammatory score, ankle perimeter and body weight. Healthy non-arthritic rats were used as controls for comparison. After 22 days of disease progression, rats were killed and bone samples collected for histology, micro-CT, three-point bending and nanoindentation analysis. Blood samples were also collected for quantification of bone turnover markers and systemic cytokines.

Results

At the tissue level, measured by nanoindentation, tofacitinib increased bone cortical and trabecular hardness. However, micro-CT and three-point bending tests revealed that tofacitinib did not reverse the effects of arthritis on the cortical and trabecular bone structure and on mechanical properties.

Conclusion

Possible reasons for these observations might be related to the mechanism of action of tofacitinib, which leads to direct interactions with bone metabolism, and/or to the kinetics of its bone effects, which might need longer exposure.

Targeting TRAF6 E3 ligase activity with a small-molecule inhibitor combats autoimmunity

Constitutive NF-κB signaling represents a hallmark of chronic inflammation and autoimmune diseases. The E3 ligase TNF receptor-associated factor 6 (TRAF6) acts as a key regulator bridging innate immunity, pro-inflammatory cytokines, and antigen receptors to the canonical NF-κB pathway. Structural analysis and point mutations have unraveled the essential role of TRAF6 binding to the E2-conjugating enzyme ubiquitin-conjugating enzyme E2 N (Ubc13 or UBE2N) to generate Lys⁶³-linked ubiquitin chains for inflammatory and immune signal propagation. Genetic mutations disrupting TRAF6-Ubc13 binding have been shown to reduce TRAF6 activity and, consequently, NF-κB activation. However, to date, no small-molecule modulator is available to inhibit the TRAF6-Ubc13 interaction and thereby counteract NF-κB signaling and associated diseases. Here, using a high-throughput small-molecule screening approach, we discovered an inhibitor of the TRAF6-Ubc13 interaction that reduces TRAF6-Ubc13 activity both in vitro and in cells. We found that this compound, C25-140, impedes NF-κB activation in various immune and inflammatory signaling pathways also in primary human and murine cells. Importantly, C25-140 ameliorated inflammation and improved disease outcomes of autoimmune psoriasis and rheumatoid arthritis in preclinical in vivo mouse models. Hence, the first-in-class TRAF6-Ubc13 inhibitor C25-140 expands the toolbox for studying the impact of the ubiquitin system on immune signaling and underscores the importance of TRAF6 E3 ligase activity in psoriasis and rheumatoid arthritis. We propose that inhibition of TRAF6 activity by small molecules represents a promising novel strategy for targeting autoimmune and chronic inflammatory diseases.

Filgotinib for the treatment of rheumatoid arthritis

INTRODUCTION

Biologics were the first targeted therapies for rheumatoid arthritis (RA), having in common high clinical efficacy. Being proteins, they are administered parenterally. The first oral targeted small molecules approved for RA are competitive inhibitors of the Janus kinase (JAK) enzyme family which mediate signalling for a cytokine subset important in RA pathogenesis. Areas covered: Several JAK inhibitors have been developed with differing selectivity for the four JAK enzymes with a view to generating oral, multi-cytokine inhibitors. Here we review the pharmacology and clinical trial data for efficacy and safety of filgotinib, an investigational selective JAK1 inhibitor. We contextualise the contemporary approach to RA management and substantial unmet needs that remain. Expert opinion: The selectivity of filgotinib for JAK1 may have theoretical advantages in terms of limiting toxicity. However, establishing whether this is so before larger numbers of patients are exposed in phase III and beyond in the real word setting, will be difficult. Filgotinib clinical trial data to date has been encouraging with rapid, sustained efficacy with promising safety and tolerability. We are likely to see an expanding choice of approved JAK inhibitors in the clinic but it may not be straightforward to distinguish safety and efficacy differences.

Matrix Metalloproteinase Gene Activation Resulting from Disordred Epigenetic Mechanisms in Rheumatoid Arthritis

Matrix metalloproteinases (MMPs) are implicated in the degradation of extracellular matrix (ECM). Rheumatoid arthritis (RA) synovial fibroblasts (SFs) produce matrix-degrading enzymes, including MMPs, which facilitate cartilage destruction in the affected joints in RA. Epigenetic mechanisms contribute to change in the chromatin state, resulting in an alteration of gene transcription. Recently, MMP gene activation has been shown to be caused in RASFs by the dysregulation of epigenetic changes, such as histone modifications, DNA methylation, and microRNA (miRNA) signaling. In this paper, we review the role of MMPs in the pathogenesis of RA as well as the disordered epigenetic mechanisms regulating MMP gene activation in RASFs.

Baricitinib in rheumatoid arthritis: evidence-to-date and clinical potential

Biologics have changed expectation and outcomes for rheumatoid arthritis (RA). However, the optimal duration and sequence of therapy for this disease has yet to be determined. Also, a significant number of patients do not satisfactorily respond to currently available therapies. The Janus kinase (JAK) inhibitors represent a new class of therapies for RA. These drugs work uniquely by inhibiting intracellular pathways thought to be important in the pathogenesis of RA. They are available as oral agents, which is also different from the currently available biologics. Baricitinib has now been evaluated in four phase III clinical trials, and although safety concerns cannot fully be answered until the drug is studied over longer periods of time, the data to date suggest that this drug with its once daily dosing, rapid onset of action and efficacy as monotherapy represents an important addition to the RA therapeutic armamentarium. Further study and experience will better define how baricitinib will be used and by which patients.

Bortezomib followed by autologous stem cell transplantation in a patient with rheumatoid arthritis: A case report and review of the literature

RATIONALE AND PATIENTS CONCERNS

Despite the introduction of varied disease-modifying antirheumatic drugs and biological agents, a substantial proportion of patients remain untreatable. We report a 56-year-old Chinese female patient with a case of refractory rheumatoid arthritis (RA) complicated with multiple myeloma (MM) who was treated successfully with Bortezomib followed by autologous stem cell transplantation (ASCT).

DIAGNOSIS AND INTERVENTIONS

We report a 56-year-old Chinese female patient who was diagnosed as RA complicating with MM. She received 4 cycles of Bortezomib-based chemotherapy followed by ASCT. The response of her RA and MM were evaluated after every cycle of Bortezomib-based chemotherapy.

INTERVENTIONS AND OUTCOMES

After the first Bortezomib-based chemotherapy cycle, this patient's symptoms were significantly alleviated and thereafter the RA activity continued to improve. After the 4 courses of Bortezomib-based chemotherapy, the C-reactive protein was <0.5 mg/dL and the disease activity score 28-erythrocyte sedimentation rate was 2.0. No hematological or nonhematological side effects were observed during the treatment of Bortezomib.

LESSONS

Bortezomib might be a new safe and promising drug for refractory RA patients.

Efficacy and safety of tofacitinib as monotherapy in Japanese patients with active rheumatoid arthritis: a 12-week, randomized, phase 2 study

OBJECTIVES

To evaluate oral tofacitinib versus placebo for treatment of active rheumatoid arthritis in Japanese patients with inadequate response to disease-modifying antirheumatic drugs.

METHODS

In this double-blind, placebo-controlled, randomized, parallel-group, 12-week, phase 2 study (clinicaltrials.gov NCT00687193), 317 patients received tofacitinib: 1, 3, 5, 10, or 15 mg as monotherapy or placebo twice daily (BID).

PRIMARY ENDPOINT

response rate by American College of Rheumatology (ACR) ≥ 20% improvement criteria (ACR20) at week 12.

RESULTS

ACR20 response rates: 37.7% (20/53), 67.9% (36/53), 73.1% (38/52), 84.9% (45/53), and 90.7% (49/54) with tofacitinib: 1, 3, 5, 10, and 15 mg BID, respectively, versus 15.4% (8/52) with placebo (p < 0.01; all doses). Dose-dependent ACR20 responses with tofacitinib versus placebo occurred from week 2 onward (p < 0.05). Changes from baseline in 28-joint disease activity score using erythrocyte sedimentation rate improved with tofacitinib versus placebo from week 4 (p < 0.01; all doses). Six tofacitinib patients experienced treatment-related serious adverse events (AEs). Most common treatment-emergent AEs: nasopharyngitis (10% vs 12%) and hyperlipidemia (5% vs 0%). Serum creatinine, hemoglobin, and total-, low-, and high-density lipoprotein-cholesterol levels increased with tofacitinib.

CONCLUSIONS

Tofacitinib produced dose-dependent ACR20 responses and reduced disease activity. The safety profile was consistent with that reported from global monotherapy trials.

Targeted blockade of JAK/STAT3 signaling inhibits proliferation, migration and collagen production as well as inducing the apoptosis of hepatic stellate cells

Protein tyrosine kinases belonging to the Janus kinase (JAK) family are associated with many cytokine receptors, which, on ligand binding, regulate important cellular functions such as proliferation, apoptosis and differentiation. The protective effects of JAK inhibitors on fibrotic diseases such as myelofibrosis and bone marrow fibrosis have been demonstrated in previous studies. The JAK inhibitor SHR0302 is a synthetic molecule that potently inhibits all members of the JAK family, particularly JAK1. However, its effect on hepatic fibrosis has not been investigated to date, to the best of our knowledge. In the present study, the effects of SHR0302 on the activation, proliferation, migration and apoptosis of hepatic stellate cells (HSCs) as well as HSC collagen production were investigated. Our data demonstrated that treatment with SHR0302 (10-9-10-5 mol/l) exerted an inhibitory effect on the activation, proliferation and migration of HSCs. In addition, the expression of collagen I and collagen III were significantly decreased following treatment with SHR0302. Furthermore, SHR0302 induced the apoptosis of HSCs, which was demonstrated by Annexin V/PI staining. SHR0302 significantly increased the activation of caspase-3 and Bax in HSCs whereas it decreased the expression of Bcl-2. SHR0302 also inhibited the activation of Akt signaling pathway. The pharmacological inhibition of the JAK1/signal transducer and activator of transcription (STAT)3 pathway led to the disruption of functions essential for HSC growth. Taken together, these findings provide evidence that SHR0302 may have the potential to alleviate hepatic fibrosis by targeting HSC functions.

Current concepts in the management of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by inflammation and joint destruction that causes significant morbidity and mortality. However, the combined use of methotrexate, a synthetic disease-modifying antirheumatic drug (DMARD), and biologic DMARD has revolutionized treatment of RA. Clinical remission is now realistic targets, achieved by a large proportion of RA patients, and rapid and appropriate induction of remission by intensive treatment with biological DMARD and methotrexate is prerequisite to halt joint damage and functional disabilities. However, biological DMARD is limited to intravenous or subcutaneous uses and orally available small but strong molecules have been developed. Oral administration of tofacitinib targeting the Janus kinase (JAK) is significantly effective than placebo in active patients with methotrexatenaïve, inadequately responsive to methotrexate or tumor necrosis factor (TNF)-inhibitors. The efficacy was rapid and as strong as adalimumab, a TNF-inhibitor. Meanwhile, association of tofacitinib on carcinogenicity and malignancy is under debate and further investigation on post-marketing survey would be warranted. On the other hand, discontinuation of a biological DMARD without disease flare is our next goal and desirable from the standpoint of risk reduction and cost effectiveness, especially for patients with clinical remission. Recent reports indicate that more than half of early RA patients could discontinue TNF-targeted biological DMARD without clinical flare and functional impairment after obtaining clinical remission. Contrarily, for established RA, fewer patients sustained remission after the discontinuation of biological DMARD and "deep remission" at the discontinuation was a key factor to keep the treatment holiday of biological DMARD.

Efficacy and safety of the oral Janus kinase inhibitor peficitinib (ASP015K) monotherapy in patients with moderate to severe rheumatoid arthritis in Japan: a 12-week, randomised, double-blind, placebo-controlled phase IIb study

Objective

To evaluate the efficacy, safety and dose response of a novel oral Janus kinase inhibitor, peficitinib (ASP015K), as monotherapy in Japanese patients with moderate to severe rheumatoid arthritis (RA).

Methods

In a 12-week, double-blind study, 281 adult patients with RA with active disease not on concomitant disease-modifying antirheumatic drug therapy were randomised equally to once-daily placebo or peficitinib 25, 50, 100 and 150 mg. The primary endpoint was American College of Rheumatology (ACR) 20 response in the peficitinib treatment groups versus placebo at week 12.

Results

Mean age was 53.0 years, 81.1% were female and 25.3% had previously used antitumour necrosis factor therapy. Peficitinib 50, 100 and 150 mg each showed statistically significantly higher ACR20 response rates compared with placebo, and response rates increased up to 150 mg with a statistically significant dose response. The total incidence of treatment-emergent adverse events (TEAEs) was similar between the placebo (64.3%) and peficitinib 25, 50, 100 and 150 mg groups (70.9%, 64.9%, 52.7% and 67.2%, respectively). TEAEs occurring more frequently in the peficitinib group compared with the placebo group included nasopharyngitis, increased blood creatine phosphokinase and diarrhoea. No cases of serious infections were reported. Herpes zoster occurred in four patients (two each in peficitinib 25 and 100 mg).

Conclusions

Treatment with peficitinib as monotherapy for 12 weeks in Japanese patients with moderate to severe RA is efficacious and showed acceptable safety profile. These findings support further developments of peficitinib for RA treatment.

Trial registration number

NCT01649999; Results.

Effects of tofacitinib on nucleic acid metabolism in human articular chondrocytes

OBJECTIVE

In our previous screening of chondrocyte protein profiles, the amount of adenosine monophosphate deaminase (AMPD) 2 was found to be decreased by tofacitinib. Extending the study, here we confirmed the decrease of AMPD2 by tofacitinib and further investigated effects of tofacitinib on purine nucleotide metabolism.

METHODS

Human articular chondrocytes and a chondrosarcoma cell line: OUMS-27 were stimulated with tofacitinib. Then the levels of AMPD2 and its related enzymes were investigated by Western blot. The levels of AMP and adenosine were assessed by mass spectrometry.

RESULTS

We confirmed the significant decrease of AMPD2 by tofacitinib in chondrocytes (p = 0.025). The levels of adenosine kinase and 5'-nucleotidase were decreased in chondrocytes, although they did not meet statistical significance (p = 0.067 and p = 0.074, respectively). The results from OUMS-27 were similar to those from the chondrocytes. The cellular adenosine levels were significantly decreased by tofacitinib in OUMS-27 (p = 0.014). The cellular AMP levels were increased, although they did not meet statistical significance in OUMS-27 (p = 0.066).

CONCLUSION

Our data indicate that tofacitinib increases the cellular levels of adenosine, which is known to have anti-inflammatory activity, through the downregulation of AMPD2. This would be a novel functional aspect of tofacitinib.

Emerging immunotherapies for rheumatoid arthritis

Novel treatments in development for rheumatoid arthritis target 3 broad areas: cytokines, cells, and signaling pathways. Therapies from each domain share common advantages (for example previously demonstrated efficacy, potential long-term immunomodulation, and oral administration respectively) that have stimulated research in each area but also common obstacles to their development. In this review recent progress in each area will be discussed alongside the factors that have impeded their path to clinical use.

Unmet needs in the treatment of autoimmunity: from aspirin to stem cells

As rheumatologic diseases became understood to be autoimmune in nature, the drugs used to treat this group of conditions has evolved from herbal or plant derived anti-inflammatory agents, such as salicylates, quinine and colchicine to the many recently approved biological response modifiers. These new drugs, especially the anti-tumor necrosis factor agents, have shown remarkable efficacy in autoimmune diseases, and there are new agents under investigation that will provide additional treatment options. In between, the world was introduced to cortisone and all of its derivatives, as chemical synthesis led to better, more efficacious drugs with lesser side effects. Disease modifying anti-rheumatic agents have actually been around since the first half of the 20th century, but only began to be used in the treatment of autoimmune diseases in the 1970s and 1980s. One advantage is that they have been invaluable in their ability to offer "steroid sparing" to decrease the adverse effects of steroids. Research over the past decade has resulted in a new class of drugs that influence cytokine regulatory pathways such as the Janus associated kinase inhibitors. The promise of personalized medicine now permeates current research into new pharmacological agents for the treatment of autoimmune disease. The new appreciation for the gene-environment interaction in the pathogenesis of most diseases especially those as heterogeneous as autoimmune diseases, has led to our focus on targeted therapies. Add to that the new knowledge of epigenetics and how changes in DNA and histone structure affect expression of genes that can play a role in immune signaling, and we now have a new exciting frontier for cutting edge drug development. The history of treatment of autoimmune diseases is really only a little over a century, but so much has changed, leading to increasing lifespans and improved quality of life of those who suffer from these ailments.

Biologic agents for rheumatoid arthritis: can we hypothesize new strategies of treatment?

Rheumatoid arthritis is a complex multifactorial disease, whose pathogenesis has not been fully elucidated. Biologic agents have revolutionized RA treatment, but a significant percentage of patients does not obtain an adequate response to the therapy. Most of the biologic agents do better if combined with conventional immunosuppressive DMARDs and they show a similar efficacy profile: most of the responders achieve the minimum desirable level of response (ACR20) and only few patients obtain a worthwhile clinical improvement (ACR70 or better). We need to identify new strategies of treatment, able to comply the non satisfied needs of RA patients. Taking inspiration from other medical fields, we could hypothesize a combined regimen in which biologic agents are administered simultaneously at a low or ultra-low dosage, targeting several pathogenetic mechanisms but avoiding important side effects. Alternatively it should be useful to identify rapid succession regimens in which biologic drugs are taken according to an established sequence. Research in this field is obviously not encouraged by pharmaceutical industries, but our efforts should be driven in this direction. According to these observations, adequate clinical trials should be designed to search for appropriate drugs associations and dosages.

Inhibition of IL-17 as a pharmacological approach for IBD

Several experimental approaches have been utilized, in order to critically examine the roles of IL-17 family members in intestinal inflammation. These approaches have included: (1) the use of IL-17A and IL-17F-deficient mice, (2) specific antibodies directed against IL-17, (3) an IL-17 vaccine, (4) methods to block the IL-17 receptor and (5) small-molecule inhibitors of IL-17. Previous studies found somewhat conflicting results in preclinical models of Inflammatory Bowel Disease (IBD), using specific strains of IL-17-deficient mice. This paper will review the preclinical results using various pharmacological approaches [specific IL-17 antibodies, an IL-17 receptor fusion protein, IL-12/IL-23 p40 subunit and IL-17 vaccine approaches, as well as a small molecule inhibitor (Vidofludimus)] to inhibit IL-17 in animal models of IBD. Recent clinical results in patients with IBD will also be discussed for Secukinumab (an IL-17A antibody), Brodalumab (an IL-17 receptor antibody) and two small-molecule drugs (Vidofludimus and Tofacitinib), which inhibit IL-17 as part of their overall pharmacological profiles. This review paper will also discuss some pharmacological lessons learned from the preclinical and clinical studies with anti-IL-17 drugs, as related to drug pharmacodynamics, IL-17 receptor subtypes and other pertinent factors. Finally, future pharmacological approaches of interest will be discussed, such as: (1) Retinoic acid receptor-related orphan nuclear receptor gamma t (Rorγt) antagonists, (2) Retinoic acid receptor alpha (RARα) antagonists, (3) Pim-1 kinase inhibitors and (4) Dual small-molecule inhibitors of NF-κB and STAT3, like synthetic triterpenoids.