Decreased Expression of IL-35 and Its Receptor Contributes to Impaired Megakaryopoiesis in the Pathogenesis of Immune Thrombocytopenia

Recent findings have shown that the level of interleukin-35 (IL-35) is abnormal in several autoimmune diseases. Nonetheless, whether IL-35 participates in the pathogenesis of immune thrombocytopenia (ITP) remains unclear. The current study investigates whether IL-35 modulates megakaryopoiesis. The results show that IL-35 receptors are progressively expressed on bone marrow megakaryocytes during the in vitro differentiation of CD34+ progenitors. IL-35 increases the number of megakaryocyte colony-forming units through the Akt pathway. The level of bone marrow IL-35 is reduced in ITP patients, and the decreased level of IL-35 may inhibit megakaryopoiesis. Then, the potential causes of decreased IL-35 in ITP patients are explored. The primary type of cell that secretes IL-35, known as IL-35-producing regulatory T cells (iTr35), is reduced in ITP patients. Bone marrow mesenchymal stem cells (MSCs) from ITP patients exhibit an impaired capability of inducing iTr35 due to enhanced apoptosis, which may contribute to the reduced level of bone marrow IL-35 in ITP patients. Iguratimod promotes megakaryocyte development and differentiation by elevating the expression of IL-35 receptors on megakaryocytes. Iguratimod improves response rates and reduces bleeding symptoms in corticosteroid-resistant ITP patients.

Efficacy and safety of iguratimod in the treatment of rheumatic and autoimmune diseases: a meta-analysis and systematic review of 84 randomized controlled trials

Objective: To evaluate efficacy and safety of iguratimod (IGU) in the treatment of rheumatic and autoimmune diseases. Methods: Databases such as Pubmed, Embase, Sinomed were searched (as of July 2022) to collect randomized controlled trials (RCTs) of IGU in the treatment of rheumatic and autoimmune diseases. Two researchers independently screened the literature, extracted data, assessed the risk of bias of the included literature, and performed meta-analysis using RevMan 5.4 software. Results: A total of 84 RCTs and 4 types of rheumatic and autoimmune diseases [rheumatoid arthritis (RA), ankylosing spondylitis (AS), primary Sjögren's syndrome (PSS) and Autoimmune disease with interstitial pneumonia]. Forty-three RCTs reported RA and showed that IGU + MTX therapy can improve ACR20 (RR 1.45 [1.14, 1.84], p = 0.003), ACR50 (RR 1.80 [1.43, 2.26], p < 0.0000), ACR70 (RR 1.84 [1.27, 2.67], p = 0.001), DAS28 (WMD -1.11 [-1.69, -0.52], p = 0.0002), reduce ESR (WMD -11.05 [-14.58, -7.51], p < 0.00001), CRP (SMD -1.52 [-2.02, -1.02], p < 0.00001), RF (SMD -1.65 [-2.48, -0.82], p < 0.0001), and have a lower incidence of adverse events (RR 0.84 [0.78, 0.91], p < 0.00001) than the control group. Nine RCTs reported AS and showed that IGU can decrease the BASDAI score (SMD -1.62 [-2.20, -1.05], p < 0.00001), BASFI score (WMD -1.07 [-1.39, -0.75], p < 0.00001), VAS (WMD -2.01 [-2.83, -1.19], p < 0.00001), inflammation levels (decreasing ESR, CRP and TNF-α). Thirty-two RCTs reported PSS and showed that IGU can reduce the ESSPRI score (IGU + other therapy group: WMD -1.71 [-2.44, -0.98], p < 0.00001; IGU only group: WMD -2.10 [-2.40, -1.81], p < 0.00001) and ESSDAI score (IGU + other therapy group: WMD -1.62 [-2.30, -0.94], p < 0.00001; IGU only group: WMD -1.51 [-1.65, -1.37], p < 0.00001), inhibit the inflammation factors (reduce ESR, CRP and RF) and increase Schirmer's test score (IGU + other therapy group: WMD 2.18 [1.76, 2.59], p < 0.00001; IGU only group: WMD 1.55 [0.35, 2.75], p = 0.01); The incidence of adverse events in IGU group was also lower than that in control group (IGU only group: RR 0.66 [0.48, 0.98], p = 0.01). Three RCTs reported Autoimmune disease with interstitial pneumonia and showed that IGU may improve lung function. Conclusion: Based on current evidence, IGU may be a safe and effective therapy for RA, AS, PSS and autoimmune diseases with interstitial pneumonia. Systematic Review Registration: (CRD42021289489).

Efficacy of iguratimod on mineral and bone disorders after kidney transplantation: a preliminary study

BACKGROUND

Iguratimod has been shown to promote bone formation and inhibit bone resorption in rheumatoid arthritis patients. We aimed to explore its effect on bone metabolism and vascular calcification (VC) in kidney transplant recipients (KTRs).

METHODS

A post hoc analysis was conducted among the subjects in our previous randomized clinical trial (NCT02839941). Forty-three KTRs completing bone metabolism 52 weeks after enrollment were selected for this analysis, among whom 27 patients received VC examinations. In the iguratimod group, iguratimod (25 mg twice daily) was added adjuvant to the traditional triple regimen. At the 52-week follow-up, the following parameters were assessed: serum calcium, phosphorus, 25-hydroxyvitamin D, intact parathyroid hormone (iPTH), bone alkaline phosphatase (BALP), osteocalcin, type I collagen N-terminal peptide (NTx), type I collagen C-terminal peptide (CTx), bone mineral density (BMD) of the femoral neck and lumbar spine, coronary artery calcification (CAC) and thoracic aortic calcification (TAC). Bone metabolic and VC indices were compared between the two groups using the independent samples t test and Wilcoxon nonparametric test.

RESULTS

At 52 weeks after enrollment, the iguratimod group had lower osteocalcin (p = 0.010), BALP (p = 0.015), NTx (p = 0.007), CTx (p = 0.012), CAC (p = 0.080) and TAC scores (p = 0.036) than the control group. There was no significant difference in serum calcium, phosphorus, 25-hydroxyvitamin D, iPTH and BMD between the groups. Iguratimod could reduce bone turnover markers (BTMs) at both high and low iPTH levels. The adverse effect of iguratimod was mild and tolerable.

CONCLUSION

Iguratimod is safe, can reduce BTMs and may could attenuate VC in the first year after KT.

Research progress on the clinical application and mechanism of iguratimod in the treatment of autoimmune diseases and rheumatic diseases

Autoimmune diseases are affected by complex pathophysiology involving multiple cell types, cytokines, antibodies and mimicking factors. Different drugs are used to improve these autoimmune responses, including nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, antibodies, and small molecule drugs (DMARDs), which are prevalent clinically in the treatment of rheumatoid arthritis (RA), etc. However, low cost-effectiveness, reduced efficacy, adverse effects, and patient non-response are unattractive factors driving the development of new drugs such as iguratimod. As a new disease-modifying antirheumatic drug, iguratimod has pharmacological activities such as regulating autoimmune disorders, inflammatory cytokines, regulating immune cell activation, differentiation and proliferation, improving bone metabolism, and inhibiting fibrosis. In recent years, clinical studies have found that iguratimod is effective in the treatment of RA, SLE, IGG4-RD, Sjogren 's syndrome, ankylosing spondylitis, interstitial lung disease, and other autoimmune diseases and rheumatic diseases. The amount of basic and clinical research on other autoimmune diseases is also increasing. Therefore, this review systematically reviews the latest relevant literature in recent years, reviews the research results in recent years, and summarizes the research progress of iguratimod in the treatment of related diseases. This review highlights the role of iguratimod in the protection of autoimmune and rheumatic bone and related immune diseases. It is believed that iguratimod's unique mode of action and its favorable patient response compared to other DMARDs make it a suitable antirheumatic and bone protective agent in the future.

Iguratimod Ameliorates the Severity of Secondary Progressive Multiple Sclerosis in Model Mice by Directly Inhibiting IL-6 Production and Th17 Cell Migration via Mitigation of Glial Inflammation

We previously reported a novel secondary progressive multiple sclerosis (SPMS) model, progressive experimental autoimmune encephalomyelitis (pEAE), in oligodendroglia-specific Cx47-inducible conditional knockout (Cx47 icKO) mice. Based on our prior study showing the efficacy of iguratimod (IGU), an antirheumatic drug, for acute EAE treatment, we aimed to elucidate the effect of IGU on the SPMS animal model. We induced pEAE by immunizing Cx47 icKO mice with myelin oligodendrocyte glycoprotein peptide 35-55. IGU was orally administered from 17 to 50 days post-immunization. We also prepared a primary mixed glial cell culture and measured cytokine levels in the culture supernatant after stimulation with designated cytokines (IL-1α, C1q, TNF-α) and lipopolysaccharide. A migration assay was performed to evaluate the effect of IGU on the migration ability of T cells toward mixed glial cell cultures. IGU treatment ameliorated the clinical signs of pEAE, decreased the demyelinated area, and attenuated glial inflammation on immunohistochemical analysis. Additionally, IGU decreased the intrathecal IL-6 level and infiltrating Th17 cells. The migration assay revealed reduced Th17 cell migration and IL-6 levels in the culture supernatant after IGU treatment. Collectively, IGU successfully mitigated the clinical signs of pEAE by suppressing Th17 migration through inhibition of IL-6 production by proinflammatory-activated glial cells.

Iguratimod efficacy in palindromic rheumatism treatment

BACKGROUND

As a new immunomodulator for rheumatoid arthritis, iguratimod (IGU) also has therapeutic potential in other immune diseases. In this study, we determined the effects of IGU on disease control in patients with palindromic rheumatism (PR).

METHODS

Patients with PR were divided into Control group (Ctrl group) and an IGU treatment (IGU group) groups. Drug efficacy was evaluated according to the frequency of PR attacks (monthly), the visual analog scale (VAS) score of patient pain, and clinical symptoms.

RESULTS

The drug positivity and disease control rates of the IGU group (100.00% and 90.91%, respectively) were significantly higher than those of the Ctrl group (61.11% and 5.56%; p = .002 and p < .001, respectively). The median number of PR flares and the VAS score of patients in the Ctrl group decreased from 3.00 (1.00-15.00) to 0.83 (0.00-12.00) and from 5 (4-6) to 4 (1-6), respectively. In the IGU group, the median number of PR attacks decreased from 4.50 (2.00-15.00) to 0.00 (0.00-0.33), and the VAS score decreased from 5 (4-6) to 0 (0-2). The IGU group exhibited a significant reduction in PR flare frequency and improvement in the VAS value (p < .001 and p < .001, respectively).

CONCLUSION

Our study is the first to describe the efficacy of IGU in PR treatment. IGU can significantly reduce the number of PR flares and improve the clinical symptoms of patients with PR.

Iguratimod as an alternative therapy for systemic sclerosis and prevention of the occurrence of ischemic digital ulcer

Objectives

This study aimed to assess the effectiveness of iguratimod (IGU) as an alternative treatment for systemic sclerosis (SSc), especially in the prevention of ischemic digital ulcers (DUs).

Methods

We constructed two cohorts from the Renji SSc registry. In the first cohort, SSc patients receiving IGU were observed prospectively with effectiveness and safety. In the second cohort, we picked up all the DU patients with at least a 3-month follow-up to investigate the prevention of IGU on ischemic DU.

Results

From 2017 to 2021, 182 SSc patients were enrolled in our SSc registry. A total of 23 patients received IGU. With a median follow-up of 61 weeks (IQR: 15-82 weeks), the drug persistence was 13/23. In total, 91.3% of the patients (21/23) became free of deterioration in the last visit with IGU. Of note, 10 patients withdrew from the study due to the following reasons: two patients withdrew due to deterioration, three due to incompliance, and five due to mild-to-moderate side effects. All the patients with side effects recovered fully after stopping IGU. Of note, 11 patients had ischemic DU, and 8 out of 11 (72.7%) patients had no new occurrence of DU during the follow-up. In the second cohort of 31 DU patients receiving a combination of vasoactive agents with a median follow-up of 47 weeks (IQR, 16-107 weeks), IGU treatment was protective of new DU occurrence (adjusted risk ratio = 0.25; 95% CI, 0.05-0.94; adjusted odds ratio = 0.07; and 95% CI, 0.01-0.49).

Conclusion

Our study for the first time describes the potential of IGU possibly as an alternative treatment for SSc. To our surprise, this study provides a hint that IGU treatment can be used for the prevention of the occurrence of ischemic DU and merits further investigation.

Iguratimod inhibits skin fibrosis by regulating TGF-β1/Smad signalling pathway in systemic sclerosis

BACKGROUND

Iguratimod (T-614), exerting a powerful anti-inflammatory ability, has therapeutic efficacy in multiple autoimmune diseases. However, the effect of T-614 on systemic sclerosis (SSc) is unclear. Here, we investigate the effect and molecular mechanism of T-614 in experimental SSc models.

METHODS

In vitro, cultured dermal fibroblasts from four SSc patients were subjected to different doses of T-614 in the presence or absence of TGF-β1 stimulation. Cell proliferation, apoptosis and migration were determined by CCK-8, flow cytometry and transwell assay, respectively. Fibrosis markers and smad signalling pathway-related proteins were detected by immunoblotting and immunofluorescence. In vivo, a bleomycin-induced SSc mouse model was used to evaluate the effect of T-614 on skin fibrosis. Pathological changes in skin tissues were evaluated by HE, Masson staining and immunohistochemistry.

RESULTS

In the study, we found T-614 inhibited TGF-β1-induced cell proliferation, migration and promoted apoptosis in a dose-dependent manner (all p < 0.01). T-614 partially reversed TGF-β1-induced upregulation of fibrosis markers and phosphorylation of smad2 and smad3 and blocked p-Smad3 nuclear translocation (all p < 0.05), suggesting T-614 may inhibit dermal fibroblasts activation by regulating TGF-β1/smad pathway. In vivo experiments, T-614 alleviated skin thickness in bleomycin-induced SSc mice (all p < 0.05). The expression of fibrosis markers and the infiltration of macrophages in skin tissue were significantly decreased after T-614 treatment (all p < 0.05).

CONCLUSION

Our preliminary data indicated T-614 inhibited dermal fibroblasts activation and skin fibrosis at least partly by regulating TGF-β1/smad pathway in experimental SSc models and may be a promising therapeutic agent for SSc.

Iguratimod Restrains Circulating Follicular Helper T Cell Function by Inhibiting Glucose Metabolism via Hif1α-HK2 Axis in Rheumatoid Arthritis

Iguratimod (IGU) is a novel disease modified anti-rheumatic drug, which has been found to act directly on B cells for inhibiting the production of antibodies in rheumatoid arthritis (RA) patients. Follicular helper T (Tfh) cells, a key T cell subsets in supporting B cell differentiation and antibody production, have been shown to play critical roles in RA. However, whether IGU can inhibit RA Tfh cells which further restrains B cell function remains unclear. Here, we aimed to explore the roles of IGU in regulating RA circulating Tfh (cTfh) cell function and investigate the potential mechanism associated with cell glucose metabolism. In our study, we found that IGU could act on RA-CD4⁺ T cells to reduce T cell-dependent antibody production. IGU decreased the percentage of RA cTfh cells and the expression of Tfh cell-related molecules and cytokines which were involved in B cell functions. Importantly, our data showed that IGU significantly restrained the cTfh cell function by inhibiting glucose metabolism, which relied on Hif1α-HK2 axis. In summary, we clarified a new target and mechanism of IGU by restraining RA cTfh cell function via inhibiting Hif1α-HK2-glucose metabolism axis. Our study demonstrates the potential application of IGU in the treatment of diseases related to abnormal metabolism and function of Tfh cells.

Iguratimod Versus Salazosulfapyridine in Rheumatoid Arthritis Patients with an Inadequate Response to Methotrexate: Adjusted with Propensity Score Matching

OBJECTIVES

Methotrexate (MTX) is recommended as a first-line conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) for treating rheumatoid arthritis (RA). No studies have established which csDMARDs are useful as add-on drugs for RA patients with an inadequate response (IR) to MTX. This retrospective study sought to identify an add-on csDMARD treatment strategy for RA patients with MTX-IR.

PATIENTS AND METHODS

We collected the cases of RA patients treated with salazosulfapyridine (SASP) or iguratimod (IGU) as the additional csDMARD for MTX-IR during a 24-month follow-up at four institutions in Japan. We performed propensity score matching to evaluate the retention rate, clinical efficacy, and safety profile (n=54, each group).

RESULTS

The retention rates at 24 months of combination therapy in the patients with any-reason discontinuations were 38.5% (MTX+SASP group) and 67.8% (MTX+IGU group). At 3 and 6 months of follow-up, the MTX+IGU group's DAS28-CRP was significantly decreased versus the MTX+SASP group, and at 3 months the MTX+IGU group's good-responder percentage (22.9%) was significantly higher versus the MTX+SASP group's (10.7%). Conversely, compared to the MTX+SASP group, the MTX+IGU group showed a greater reduction in the eGFR from baseline after 3 months during follow-up.

CONCLUSIONS

IGU is a useful add-on csDMARD for RA patients with MTX-IR; its high retention rate and good clinical response make it a useful combination therapy for controlling RA disease activity. However, the renal function of these patients should be monitored during follow-up.

Allergic Skin Rash Caused by Iguratimod: A Report of Two Cases

Iguratimod has been used in the treatment of rheumatoid arthritis and Sjogren's syndrome (SS). Herein, we report two cases of skin allergic reactions caused by iguratimod in our hospital. Case 1 was a woman with SS who developed diffuse pruritus erythema after three weeks of combination therapy of hydroxychloroquine (HCQ) and iguratimod. When the patient was again prescribed iguratimod after the rash subsided, the pruritus erythema reappeared. Case 2 was a 23-year-old girl treated with prednisone, HCQ, and mycophenolate mofetil for systemic lupus erythematosus and SS. In the follow-up treatment, mycophenolate mofetil was replaced by iguratimod. On the 20th day of treatment, a pruritic erythematous maculopapular rash appeared. To the best of our knowledge, this is the first study to report the characteristics of an allergic rash caused by iguratimod. It is better to administer HCQ and iguratimod successively rather than simultaneously to a patient.

The addition of iguratimod can reduce methotrexate dose in rheumatoid arthritis with clinical remission

OBJECTIVES

We prospectively evaluated whether the addition of iguratimod (IGU) could sustain clinical remission in rheumatoid arthritis (RA) patients after tapering of methotrexate (MTX).

METHODS

The study included 47 patients; 25 patients in the MTX maintenance group, and 22 patients in the IGU addition group who were treated with additional IGU and tapering of MTX dose. Clinical efficacy and safety were evaluated at 12, 24, and 36 weeks.

RESULTS

In the IGU addition group, the dose of MTX could be reduced from 8.6 ± 2.4 mg/week at baseline to 4.7 ± 2.2 mg/week at 36 weeks (p < .001). Clinical remission was maintained (disease activity score [DAS]28-ESR 1.48 ± 0.63 at baseline and 1.69 ± 0.76 at 36 weeks, p = .911), and disease activity remained low (clinical disease activity index [CDAI] 2.4 ± 1.5 at baseline and 3.1 ± 3.4 at 36 weeks, p = .825). The US-GLOSS score significantly decreased from 9.2 ± 5.3 at baseline to 6.4 ± 4.3 at 36 weeks (p = .034). In the IGU addition group, two patients discontinued IGU because of stomatitis and three patients relapsed during the follow-up period (flare rate: 15.0%). There was no significant difference in RA disease activity at 36 weeks between the two groups.

CONCLUSION

Additional use of IGU can effectively reduce the MTX dose required by patients during clinical remission without inducing a flare.

Iguratimod Alleviates Myocardial Ischemia/Reperfusion Injury Through Inhibiting Inflammatory Response Induced by Cardiac Fibroblast Pyroptosis via COX2/NLRP3 Signaling Pathway

Background: NLRP3 inflammasome contributes a lot to sterile inflammatory response and pyroptosis in ischemia/reperfusion (I/R) injury. Cardiac fibroblasts (CFs) are regarded as semi-professional inflammatory cells and they exert an immunomodulatory role in heart. Iguratimod provides a protective role in several human diseases through exerting a powerful anti-inflammatory effect. However, it is still unclear whether iguratimod could alleviate myocardial I/R injury and whether inflammation triggered by NLRP3-related pyroptosis of CFs is involved in this process. Methods: Transcriptomics analysis for GSE160516 dataset was conducted to explore the biological function of differentially expressed genes during myocardial I/R. In vivo, mice underwent ligation of left anterior descending coronary artery for 30 min followed by 24 h reperfusion. In vitro, primary CFs were subjected to hypoxia for 1 h followed by reoxygenation for 3 h (H/R). Iguratimod was used prior to I/R or H/R. Myocardial infarct area, serum level of cardiac troponin I (cTnI), pathology of myocardial tissue, cell viability, lactate dehydrogenase (LDH) release, and the expression levels of mRNA and protein for pyroptosis-related molecules were measured. Immunofluorescence was applied to determine the cellular localization of NLRP3 protein in cardiac tissue. Results: During myocardial I/R, inflammatory response was found to be the most significantly enriched biological process, and nucleotide-binding oligomerization domain (NOD)-like receptor signaling was a crucial pathway in mediating cardiac inflammation. In our experiments, pretreatment with iguratimod significantly ameliorated I/R-induced myocardial injury and H/R-induced pyroptosis of CFs, as evidenced by reduced myocardial infarct area, serum cTnI level, and LDH release in supernatants, as well as improved pathology of cardiac tissue and cell viability. Immunofluorescence analysis showed that NLRP3 was mainly localized in CFs. Moreover, iguratimod inhibited the expression of pro-inflammatory cytokines and pyroptosis-related molecules, including NLRP3, cleaved caspase-1, and GSDMD-N. Conclusion: Our results suggested that inflammatory response mediated by NOD-like receptor signaling is of vital importance in myocardial I/R injury. Iguratimod protected cardiomyocytes through reducing the cascade of inflammation in heart by inhibiting cardiac fibroblast pyroptosis via the COX2/NLRP3 signaling pathway.

Iguratimod: Novel Molecular Insights and a New csDMARD for Rheumatoid Arthritis, from Japan to the World

Iguratimod (IGU) is a conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) routinely prescribed in Japan since 2012 to patients with rheumatoid arthritis (RA). Iguratimod acts directly on B cells by inhibiting the production of inflammatory cytokines (tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-8, IL-17), thereby suppressing the production of immunoglobulin and inhibiting the activity of nuclear factor kappa-light chain enhancer of activated B cells. In Japan, it is one of the most used csDMARDs in daily practice, but it is not recommended as a treatment for RA due to the lack of large-scale evidence established overseas. However, recent reports on the novel pharmacological effects of IGU on lymphocytes and synovial fibroblasts, as well as its efficacy in daily practice, have increased its importance as a drug for the treatment of RA. In this review, we highlighted the basic and clinical studies in IGU and discuss its potential as a new therapeutic agent for the treatment of RA.

Effectiveness and Safety of Iguratimod in Treating Primary Sjögren's Syndrome: A Systematic Review and Meta-Analysis

Objectives: We aimed to assess the effectiveness and safety of iguratimod (IGU) in treating primary Sjögren’s syndrome (pSS) by meta-analysis.

Methods: Eight databases and two clinical trial websites were searched from conception to August 10, 2020, for relevant randomized controlled trials (RCTs) on outcomes of patients with pSS treated with IGU. Revman 5.4 was used for statistical analysis and creating plots.

Results: A total of 1,384 patients with pSS from 19 RCTs were included in this meta-analysis. Pooled results demonstrated that patients treated with IGU + hydroxychloroquine (HCQ) + glucocorticoid (GC) showed significant differences in erythrocyte sedimentation rate (ESR), rheumatoid factor (RF) level, platelet (PLT) count, immunoglobulin G (IgG) level, salivary flow rate, Schirmer’s test result, EULAR Sjögren’s Syndrome Patient Reported Index (ESSPRI), EULAR Sjögren’s Syndrome Disease Activity Index (ESSDAI), and efficacy rate (p ≤ 0.01) compared to patients treated with HCQ + GC. Compared to treatment with HCQ and GC, co-administration of IGU with GC showed significant differences in ESR and RF level (p ≤ 0.01); however, no significant differences were noted in IgG level. Conversely, the IgG level showed a significant improvement in the IGU + HCQ + GC group compared to the HCQ + GC group. The results of safety analysis revealed that seven trials showed no significant differences in adverse events (AEs) between the IGU + HCQ + GC and HCQ + GC groups (p = 0.15). Although no severe AEs were noted, gastrointestinal discomfort was the most common AE in the IGU group. No significant differences in AEs were observed between the IGU + GC and HCQ + GC groups.

Conclusion: IGU improved the clinical symptoms of patients with pSS, including inflammatory indicators (ESR, IgG, and RF levels), PLT count, secretion function of the salivary and lacrimal glands (salivary flow rate and Schirmer’s test result), and disease indexes (ESSDAI and ESSPRI), when co-administered with HCQ + GC therapy without increasing the risks of AEs. Therefore, IGU can be considered as an effective and safe drug for clinical therapy of pSS. Considering the limitations of the present trials, more long-term, multicenter, and high-quality RCTs are required to assess the effectiveness and safety of IGU for treating patients with pSS.

Effect of combined application of iguratimod in the treatment of active rheumatoid arthritis on bone metabolism, Th17 cells and Treg cells

OBJECTIVE

This study was designed to analyse the effect of combined application of iguratimod with methotrexate in the treatment of active rheumatoid arthritis (RA).

METHODS

A total of 115 patients with active RA admitted to our hospital were enrolled and divided into group A (n=58) and group B (n=57) according to the method of random number table. Patients in group B were treated with methotrexate alone, while patients in group A were treated with methotrexate combined with iguratimod. The curative efficacy was compared between the two groups.

RESULTS

At 6 months after treatment, the levels of CTX-1 and RANKL in group A were higher than those in group B, and the levels of OPG, IL-17 and TGF-α in group A were lower than those in group B (P<0.05). The level of Th17 cells in group A was higher than that in group B, and the level of Treg cells in group A was lower than that in group B at 6 months after treatment (P<0.05). Tender joints count, swollen joints count and DAS28 score in group A were less than those in group B at 6 months after treatment (P<0.05). The duration of morning stiffness of the joints and the score of joint pain degree in group A were less than those in group B at 1, 2, 3, 4, 5, and 6 months after treatment (P<0.05).

CONCLUSION

The combined application of methotrexate and iguratimod in the treatment of active RA can effectively improve bone metabolism, regulate the levels of Th17 and Treg cells, play a prominent role in anti-inflammatory effect, and relieve symptoms, and thus achieve a more satisfactory curative effect.

The Effectiveness and Retention Rate of Iguratimod in Japanese Rheumatoid Arthritis Patients with/without Methotrexate in Daily Medical Care

(1) Background: We evaluated the clinical response of iguratimod (IGU) in patients with rheumatoid arthritis (RA) being treated with or without methotrexate (MTX) over 54 weeks. (2) Methods: 106 patients with RA undergoing IGU were retrospectively observed. RA patients were divided into those treated with MTX+IGU (n = 35) and those treated with IGU (n = 71). The primary endpoint was the clinical response of the Disease Activity Score assessing 28 joints with C-reactive protein (DAS28-CRP) differences in the changes from baseline to 54 weeks between MTX+IGU and IGU groups. Secondary endpoints, such as the clinical response, retention rate, and safety, were evaluated. (3) Results: The DAS28-CRP difference in the changes between the two groups were −0.2. DAS28-CRP were significantly reduced from the baseline in the MTX+IGU and IGU groups (−1.43 and −1.20 from baseline, respectively). The retention rates were 71.4% in the MTX+IGU groups and 59.2% in the IGU groups (p = 0.16). Adverse events were observed in a total of 6 (17.1%) MTX+IGU patients and 20 (28.2%) IGU patients (p = 0.21). (4) Conclusions: IGU therapy may be a useful treatment option for patients who cannot be treated with MTX.

Efficacy of add-on iguratimod in patients with rheumatoid arthritis who inadequately respond to either tocilizumab or tumor necrosis factor alpha inhibitors

OBJECTIVES

This study aimed to evaluate the efficacy of add-on iguratimod (IGU) in patients with rheumatoid arthritis (RA patients) who inadequately respond to either tocilizumab (TCZ) or tumor necrosis factor alpha inhibitors (TNFi).

METHODS

Twenty-three RA patients treated with TCZ (the TCZ group) and 23 RA patients treated with TNFi (the TNFi group) were enrolled in this 24-week retrospective study from our multicenter registry. All inadequate responders to either TCZ or TNFi received add-on IGU. Baseline demographics and disease activity at 24 weeks after initiating add-on IGU were compared between the two groups.

RESULTS

Baseline clinical disease activity index (CDAI) values in the TCZ group and TNFi group were 14.1 and 11.8 (p = .24 between the two groups). At 24 weeks, CDAI values in the TCZ group and TNFi group were 5.1 and 7.5 (p = .002 and .002 compared to baseline, respectively) and ΔCDAI values were -9.0 and -4.3 (p = .007 between the two groups). Multiple linear regression analysis revealed that add-on IGU in the TCZ group was associated with greater improvement in CDAI relative to the TNFi group.

CONCLUSION

Add-on IGU was more effective in inadequate responders to TCZ than in inadequate responders to TNFi.

Iguratimod as a New Drug for Rheumatoid Arthritis: Current Landscape

Iguratimod (IGU) is a novel synthetic small molecule disease modified anti-rheumatic drug approved only in Japan and China up to date. IGU plays an important immunomodulatory role in the synovial tissue of rheumatoid arthritis by inhibiting the production of immunoglobulins and cytokines and regulating T lymphocyte subsets. IGU also regulates bone metabolism by stimulating bone formation while inhibiting osteoclast differentiation, migration, and bone resorption. In clinical trials, IGU was shown to be superior to placebo and not inferior to salazosulfapyridine. Combined therapy of IGU with other disease-modifying anti-rheumatic drugs showed significant improvements for disease activity. IGU has good efficacy and tolerance as an additional treatment for rheumatoid arthritis patients with inadequate response to methotrexate and biological disease-modifying anti-rheumatic drugs. In this review, we summarize current landscape on the mechanism of action of IGU and its clinical effectiveness and safety. It is expected that further translational studies on IGU will pave the road for wider application of IGU in the treatment of autoimmune diseases other than rheumatoid arthritis.

In Situ Forming Injectable Hydrogel For Encapsulation Of Nanoiguratimod And Sustained Release Of Therapeutics

Background

Iguratimod (IGUR) is a novel disease-modifying antirheumatic drug used for treating rheumatoid arthritis (RA). To improve its bioavailability and to alleviate gastrointestinal side effects, we changed the formulation into nanoiguratimod-loaded hydrogel (NanoIGUR-loaded hydrogel) composites for sustained release of therapeutics.

Methods

IGUR was first encapsulated in biodegradable polyvinyl alcohol micelle by liquid antisolvent precipitation (LAP) technology, and then loaded into an in situ injectable hyaluronic acid hydrogel, which was cross-linked by PEG (Thiol)₂ (HS-PEG-SH) through Michael addition reaction. In vitro, the biological effects (proliferation, migration, and invasion) of NanoIGUR-loaded hydrogel on fibroblast-like synoviocytes (RA-FLS) from RA patients were evaluated. In vivo, the pharmacokinetics of NanoIGUR-loaded hydrogel was assessed and the efficacy of NanoIGUR-loaded hydrogel in treating collagen-induced arthritis (CIA) rats was evaluated.

Results

By the LAP technique, we acquired the amorphous form nanoiguratimod, with an average size of 458 nm, which had higher dissolution rates and higher stability. The release of IGUR from hydrogel composite in PBS was gradual and sustained for up to 72 hrs compared with nanoiguratimod. Different concentrations of NanoIGUR-loaded hydrogel inhibited the proliferation, migration, and invasion of RA-FLS. The pharmacokinetic parameters showed better bioavailability and longer half-life time with NanoIGUR-loaded hydrogel by subcutaneous administration than oral raw iguratimod. Animal experiments confirmed that subcutaneous injection of NanoIGUR-loaded hydrogel (10 mg/kg every 3 days) and oral raw iguratimod (10mg/kg daily) showed similar efficacy in decreasing arthritis index score, pathological score, and expression of inflammatory cytokines.

Conclusion

Overall, we demonstrate that NanoIGUR-loaded hydrogel provides a new route of administration and extends the administration interval. It could be a promising drug-delivery approach in the management of RA.

Efficacy and safety of iguratimod plus corticosteroid as bridge therapy in treating mild IgG4-related diseases: A prospective clinical trial

Aim

The purpose of this study is to evaluate the therapeutic efficacy and safety of iguratimod plus corticosteroid as bridge therapy in the treatment of mild immunoglobulin G4‐related disease (IgG4‐RD).

Methods

Newly diagnosed IgG4‐RD patients, without internal organ involvement were enrolled. Patients were given one dose of diprospan, intramuscular injection, and iguratimod, 25 mg, twice daily, for 24 weeks and were followed up at 0, 12 and 24 weeks. Follow‐up indexes included IgG4‐RD responder index (IgG4‐RD RI), serology and imaging, plasma cytokines and adverse drug effect. Flow cytometry was performed for T, B cell subsets and plasma was collected for liquid chromatography mass spectrometry (LC‐MS)‐based metabolomic profiling and data processing.

Results

Thirty patients were enrolled. At week 24, 9 (30.0%) patients achieved complete response, 17 (56.7%) patients with partial response, and 4 (13.3%) patients had no response to treatment. IgG4‐RD RI, serum IgG and IgG4 levels decreased significantly at weeks 12 and 24 after treatment, as well as CD3+ CD8+ T cells, plasmablast/plasma cells and memory B cells. The LC‐MS based plasma metabolomic profiles revealed significant changes between untreated patients and healthy donors, which became much similar to normal states after treatment.

Conclusion

Iguratimod plus corticosteroid as bridge therapy is effective for the treatment of mild IgG4‐RD, it can improve the clinical symptoms, reduce serum IgG and IgG4 levels, especially plasmablasts/plasma cells and memory B cells. In addition, the metabolite profiling became similar to normal controls after treatment.

Efficacy of iguratimod vs. salazosulfapyridine as the first-line csDMARD for rheumatoid arthritis

Objectives: We retrospectively evaluated the retention rate and clinical responses following treatment for rheumatoid arthritis (RA) with iguratimod (IGU) vs. salazosulfapyridine (SASP) as the first-line conventional synthetic disease-modifying antirheumatic drug (csDMARD).Methods: We analyzed 197 RA patients who were treated with IGU or SASP as the initial treatment in the 3-year study period. The retention rate, clinical response, the dosage and percent user of prednisolone (PSL), and safety profiles were evaluated.Results: At month 36, the retention rates of the IGU and SASP groups were 52.4 vs. 32.1%. The rate of responders (good or moderate response) at month 36 was 85.8 vs. 65.2% in the IGU and SASP groups, respectively. At month 36 for the IGU and SASP groups, the percentages of PSL users were 16.7 vs. 46.7%, and the PSL dosage was 0.3 mg/d vs. 2.0 mg/d, respectively. The cumulative rates of any adverse event (AE) at month 36 were 19.8 vs. 29.2% in the IGU and SASP groups, respectively.Conclusion: IGU is a useful first-line csDMARD treatment for RA patients, showing a high retention rate and good efficacy without an increased risk of serious AEs, including serious infections. Our findings also indicate a PSL dose-sparing effect of IGU treatment.

A rapid and sensitive LC-MS/MS method for analysis of iguratimod in human plasma: Application to a pharmacokinetic study in Chinese healthy volunteers

A rapid, sensitive and reproducible LC-MS/MS method was developed and validated to determine iguratimod in human plasma. Sample preparation was achieved by protein precipitation with acetonitrile. Chromatographic separation was operated on an Ultimate® XB-C18 column (2.1 × 50 mm, 3.5 μm, Welch) with a flow rate of 0.400 mL/min, using a gradient elution with acetonitrile and water which contained 2 mm ammonium acetate and 0.1% formic acid as the mobile phase. The detection was performed on a Triple Quad™ 5500 mass spectrometer coupled with an electrospray ionization interface under positive-ion multiple reaction monitoring mode with the transition ion pairs of m/z 375.2 → 347.1 for iguratimod and m/z 244.3 → 185.0 for agomelatine (the internal standard), respectively. The method was linear over the range of 5.00-1500 ng/mL with correlation coefficients ≥0.9978. The accuracy and precision of intra- and inter-day, dilution accuracy, recovery and stability of the method were all within the acceptable limits and no matrix effect or carryover was observed. As a result, the main pharmacokinetic parameters of iguratimod were as follows: Cmax , 1074 ± 373 ng/mL; AUC0-72 , 13591 ± 4557 ng h/mL; AUC0-∞ , 13,712 ± 4613 ng h/mL; Tmax , 3.29 ± 1.23 h; and t1/2 , 8.89 ± 1.23 h.

Genetic predictors of efficacy and toxicity of iguratimod in patients with rheumatoid arthritis

Iguratimod (IGU) is a novel disease-modifying anti-rheumatic drug (DMARD) in rheumatoid arthritis (RA). Like other DMARDs, IGU exhibited significant differences in effectiveness and safety.

AIM

The aim of this study was to identify genetic predictorsof efficacyand toxicity of IGU in patients with RA.

MATERIALS & METHODS

Seven SNPs from IGU-metabolizing genes were genotyped in 272 IGU-treated patients with RA. Results: ABCG2 rs2231142 A allele conferred a higher response to IGU, while NAT2 rs1495742 G carriersconferred a lower response to IGU. CYP2C19*2 rs4244285 A carriers had higher risk for IGU-induced toxicity compared to the GG carriers.

CONCLUSION

Our study suggests that the polymorphisms of ABCG2 (rs2231142), NAT2 (rs1495741)and CYP2C19*2 (rs4244285) may help to predict thetherapeutic effectiveness and toxicity of IGU in patients with RA.

Anti-rheumatic drug iguratimod protects against cancer-induced bone pain and bone destruction in a rat model

The bone is one of the most common sites of metastasis in patients with cancer. Current treatments for bone metastases include bisphosphonates, denosumab, non-steroidal anti-inflammatory drugs and analgesics, but each of them has certain limitations. Cytokines and mediators released from various cells in the bone microenvironment may drive a vicious cycle of osteolytic bone metastases. Iguratimod (T-614), a novel disease-modifying anti-rheumatic drug, has demonstrated therapeutic effects by suppressing the production of inflammatory cytokines in rats and patients with rheumatoid arthritis. Therefore, the current study evaluated the hypothesis that iguratimod may protect against cancer-induced bone pain and bone metastasis in a rat model. For this purpose, rats inoculated with Walker 256 cells were treated with iguratimod from days 11–17 post-surgery. Mechanical paw withdrawal thresholds and expression levels of phosphorylated extracellular signal-related kinase (pERK) and c-Fos in the spinal cord were investigated to detect changes in bone pain. Bone destruction levels were detected using X-rays, hematoxylin and eosin and tartrate-resistant acid phosphatase staining. The results revealed that mechanical paw withdrawal thresholds and the expression levels of pERK and c-Fos declined in a dose-dependent manner in rats treated with iguratimod, and bone destruction severity was also reduced. These findings may provide important new insights into the treatment of bone metastasis symptoms.

Identification of Iguratimod as an Inhibitor of Macrophage Migration Inhibitory Factor (MIF) with Steroid-sparing Potential

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that has been implicated in a broad range of inflammatory and oncologic diseases. MIF is unique among cytokines in terms of its release profile and inflammatory role, notably as an endogenous counter-regulator of the anti-inflammatory effects of glucocorticoids. In addition, it exhibits a catalytic tautomerase activity amenable to the design of high affinity small molecule inhibitors. Although several classes of these compounds have been identified, biologic characterization of these molecules remains a topic of active investigation. In this study, we used in vitro LPS-driven assays to characterize representative molecules from several classes of MIF inhibitors. We determined that MIF inhibitors exhibit distinct profiles of anti-inflammatory activity, especially with regard to TNFα. We further investigated a molecule with relatively low anti-inflammatory activity, compound T-614 (also known as the anti-rheumatic drug iguratimod), and found that, in addition to exhibiting selective MIF inhibition in vitro and in vivo, iguratimod also has additive effects with glucocorticoids. Furthermore, we found that iguratimod synergizes with glucocorticoids in attenuating experimental autoimmune encephalitis, a model of multiple sclerosis. Our work identifies iguratimod as a valuable new candidate for drug repurposing to MIF-relevant diseases, including multiple sclerosis.

Anti-rheumatic drug iguratimod (T-614) alleviates cancer-induced bone destruction via down-regulating interleukin-6 production in a nuclear factor-κB-dependent manner

Cytokines are believed to be involved in a "vicious circle" of progressive interactions in bone metastasis. Iguratimod is a novel anti-rheumatic drug which is reported to have the capability of anti-cytokines. In this study, a rat model was constructed to investigate the effect of iguratimod on bone metastasis and it was found that iguratimod alleviated cancer-induced bone destruction. To further explore whether an anti-tumor activity of iguratimod contributes to the effect of bone resorption suppression, two human breast cancer cell lines MDA-MB-231 and MCF-7 were studied. The effect of iguratimod on tumor proliferation was detected by CCK-8 assay and flow cytometry. The effects of iguratimod on migration and invasion of cancer cells were determined by wound-healing and Transwell assays. Results showed that high dose (30 μg/mL) iguratimod slightly suppressed the proliferation of cancer cells but failed to inhibit their migration and invasion capacity. Interestingly, iguratimod decreased the transcription level of IL-6 in MDA-MB-231 cells in a concentration-dependent manner. Moreover, iguratimod partially impaired NF-κB signaling by suppressing the phosphorylation of NF-κB p65 subunit. Our findings indicated that iguratimod may alleviate bone destruction by partially decreasing the expression of IL-6 in an NF-κB-dependent manner, while it has little effect on the tumor proliferation and invasion.

Inhibitory Effect of Anti-rheumatic Drug Iguratimod for Hepatocellular Carcinogenesis by Inhibition of Serum Interleukin-8 Production

BACKGROUND/AIM

Angiogenesis is a known factor for the development of hepatocellular carcinoma (HCC). The aim of this study was to assess the property of iguratimod, that is an anti-inflammatory drug for rheumatoid arthritis, on anti-angiogenesis and anti-carcinogensis for HCC.

MATERIALS AND METHODS

In vitro, human umbilical vein endothelial cells were cultured under interleukin-8 (IL-8) with or without iguratimod. In vivo, a rat model with HCC received iguratimod or distilled water for 6 weeks. Diameter of the largest tumor, number of tumors and serum interleukin-8 concentration were compared between iguratimod and control groups.

RESULTS

By an in vitro angiogenesis assay, it was found angiogenesis in iguratimod group was significantly lower than that in control group (p=0.013). In vivo, largest tumor diameter (p=0.036), number of the tumor (p=0.011) and serum interleukin-8 concentration (p=0.036) in the iguratimod group were significantly smaller and lower than those in the control group.

CONCLUSION

Iguratimod may inhibit hepatocellular carcinogensis by inhibition of interleukin-8 production in a rat model.

Iguratimod for the treatment of rheumatoid arthritis in Japan

Iguratimod (IGU), a small-molecule compound, was developed as a disease-modifying antirheumatic drug in Japan. The pharmacological studies showed that inhibition of the production of cytokines and immunoglobulins mainly contributes to its improvement effect on animal arthritis models. The first clinical study of IGU in Japanese patients with rheumatoid arthritis was started in 1992 and Phase III studies were started in 1998. From the results of Phase II studies, a dose-escalating regimen was recommended to relieve the side effects. In a double-blind study comparing the efficacy and safety of the drug with those of placebo and salazosulfapyridine, it was confirmed that IGU was superior to placebo and was not inferior to salazosulfapyridine. Furthermore, a double-blind controlled trial of IGU in combination with methotrexate revealed an efficacious and manageable safety profile. IGU would be widely used as a new option for rheumatoid arthritis treatment and combination drug with methotrexate.