Concomitant iguratimod therapy in patients with active rheumatoid arthritis despite stable doses of methotrexate: a randomized, double-blind, placebo-controlled trial

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).

Effectiveness and Safety of Iguratimod Monotherapy or Combined With Methotrexate in Treating Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

Objectives: We aimed to estimate the effectiveness and safety of iguratimod (IGU) monotherapy or in combination with methotrexate (MTX) in treating rheumatoid arthritis (RA) to provide an evidence-primarily-based foundation for clinical application.

Methods: We conducted a systematic review of the meta-analysis using eight databases and two clinical trial websites searching for randomized controlled trials (RCTs) from conception to 15 March 2022, based on outcomes of patients with RA treated with IGU. The evidence quality assessment of primary outcomes was evaluated by the GRADE tool, and RevMan 5.3 and StataMP 14.0 were used to perform this research.

Results: A total of 4302 patients with RA from 38 RCTs was included in this research. Pooled results demonstrated as follows: 1) Compared with methotrexate (MTX) alone, IGU alone was superior in improving ACR20 and DAS28-ESR, while having no significant difference in ACR50 and ACR70 [ACR20: (RR 1.15, 95% CI 1.05–1.27, p = 0.004); ACR50: (RR 0.97, 95% CI 0.66–1.44, p = 0.88); ACR70: (RR 0.92, 95% CI 0.45–1.90, p = 0.83); DAS28-ESR: mean difference (MD) −0.15, 95% CI −0.27 to −0.03, p = 0.01]. 2) Compared with MTX alone, IGU + MTX was more effective in improving ACR20, ACR50, ACR70, and DAS28-ESR. [ACR20: (RR 1.24, 95% CI 1.14–1.35, p < 0.00001); ACR50: (RR 1.96, 95% CI 1.62–2.39, p <0.00001); ACR70: (RR 1.91, 95% CI 1.41–2.57, p < 0.0001)]; [DAS28-ESR: (MD) −1.43, 95% CI −1.73 to −1.12, p < 0.00001]. 3) Compared with MTX + leflunomide (LEF), ACR20, ACR50, ACR70, and DAS28-ESR of IGU + MTX had no significant difference [ACR20: (RR 1.06, 95% CI 0.94–1.19, p = 0.38); ACR50: (RR 1.10, 95% CI 0.66–1.84, p = 0.72); ACR70: (RR 1.20, 95% CI 0.45–3.20, p = 0.71); DAS28-ESR: (MD −0.02, 95% CI −0.13 to −0.10, p = 0.77)]. 4) Compared with MTX + hydroxychloroquine (HCQ), IGU + MTX was superior in improving DAS28-ESR (MD −2.16, 95% CI −2.53 to −1.79, p < 0.00001). 5) Compared with MTX + tripterygium glycosides (TGs), IGU + MTX was more effective in improving DAS28-ESR (MD −0.94, 95% CI −2.36 to 0.48, p = 0.19). 6) There were no significant differences in adverse events (AEs) between the groups of IGU vs. MTX (RR 0.96, 95% CI 0.71–1.31, p = 0.80), IGU + MTX vs. MTX (RR 1.10, 95% CI 0.90–1.35, p = 0.34), IGU + MTX vs. MTX + HCQ (RR 0.64, 95% CI 0.29–1.42, p = 0.27), and IGU + MTX vs. MTX + TGs (RR 0.75, 95% CI 0.28–2.02, p = 0.57). The incidence of AEs in the IGU + MTX group was lower than the MTX + LEF group (RR 0.83, 95% CI 0.71–0.98, p = 0.03).

Conclusion: Compared to the MTX alone subgroup, IGU alone offers clear advantages in improving ACR20 and DAS28-ESR, despite the insufficient evidence for DAS28-ESR findings. IGU + MTX shows clear benefits in improving ACR20, ACR50, ACR70, and DAS28-ESR scores compared to standard therapies. When the intervention (IGU alone or IGU + MTX) lasted for 52 weeks, it demonstrated superior efficacy in improving ACR20 of patients without prominent adverse events. Notably, IGU or IGU + MTX has apparent advantages in improving ACR20 of first-visit RA, and IGU + MTX has obvious advantages in improving DAS28-ESR of refractory RA. Furthermore, IGU + MTX does not increase the risk of leukopenia, but it can decrease the risk of liver function tests (LFTs), regardless of the age or the stage of RA.

Clinical Trial Registration:https://www.crd.york.ac.uk/PROSPERO/#recordDetails, identifier CRD42022295217

The Effect and Safety of Iguratimod Combined With Methotrexate on Rheumatoid Arthritis: A Systematic Review and Meta-Analysis Based on a Randomized Controlled Trial

Background: Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease with inflammatory synovitis. Iguratimod (IGU) combined with methotrexate (MTX) therapy may have better efficacy and safety.

Methods: First, we searched randomized controlled trials (RCTs) of IGU + MTX in the treatment of RA through literature databases (such as PubMed, Corkland Library, CNKI, etc.) and then conducted RCT quality assessment and data extraction. Finally, we used RevMan 5.3 for meta-analysis, STATA 15.0 for publication bias assessment, and GRADE tool for the evidence quality assessment of primary outcomes. This systematic review and meta-analysis were registered in PROSPERO (CRD42021220780).

Results: This systematic review and meta-analysis included 31 RCTs involving 2,776 patients. Compared with MTX alone, the ACR20, ACR50, and ACR70 of IGU + MTX are higher, while DAS28 is lower [ACR20: (RR 1.55, 95% CI 1.14–2.13, p = 0.006); ACR50: (RR 2.04, 95% CI 1.57–2.65, p < 0.00001); ACR70: (RR 2.19, 95% CI 1.44–3.34, p = 0.00003); DAS28: (weighted mean difference (WMD) −1.65, 95% CI −2.39 to −0.91, p < 0.0001)]. Compared with MTX + leflunomide, IGU + MTX has no significant difference in improving ACR20, ACR50, ACR70, but IGU + MTX improves DAS28 more significantly [ACR20: (RR 1.09, 95% CI 0.79–1.89, p = 0.59); ACR50: (RR 1.07, 95% CI 0.64–1.78, p = 0.81); ACR70: (RR 1.17, 95% CI 0.44–3.10, p = 0.76); DAS28: (WMD −0.40, 95% CI −0.42 to −0.38, p < 0.0001)]. Compared with the MTX + tripterygium subgroup and MTX-only subgroup, the incidence of adverse events of the IGU + MTX group is of no statistical significance [MTX only: (RR 0.99, 95% CI 0.87–1.13, p = 0.90); MTX + Tripterygium: (RR 0.73, 95% CI 0.29–1.85, p = 0.50)]. However, compared with MTX + leflunomide, the incidence of adverse events in the IGU + MTX group was lower (RR 0.74, 95% CI 0.62–0.88, p = 0.0009). The quality of ACR70 was high; the quality of adverse events and ACR50 test was moderate.

Conclusion: Compared with conventional therapy, IGU + MTX may be a safer and more effective therapy for RA patients. When the intervention method is (IGU 25 mg Bid, MTX 10–25 mg once a week), and the intervention lasts for at least 12 weeks, the curative effect may be achieved without obvious adverse events.

Effectiveness of drug safety measures for reducing the incidence of adverse drug reactions: Post-hoc analysis of data from all-case surveillance of iguratimod using generalized estimating equations

A post-marketing study was performed on all patients who had started treatment with iguratimod, a conventional synthetic disease-modifying antirheumatic drug approved in Japan. During the study period, various safety measures were implemented to reduce risks. We investigated the frequency of adverse drug reactions before and after implementation of each safety measure to examine the preventive effect of these measures. Post-hoc analysis was performed using data from all-case surveillance of iguratimod. The subjects were all of the patients receiving iguratimod for whom safety information was obtained. To identify the time after starting administration when adverse drug reactions were most likely to occur, a generalized linear mixed-effect model was applied for the period from initiation of administration until occurrence of reactions in each patient. The mean incidence of adverse drug reactions per patient was compared before and after the implementation of safety measures by using generalized estimating equations based on a two-sided test, 95% confidence interval, and 5% significance level. The number of patients treated with iguratimod was not related to changes in the number of patients with adverse drug reactions. After implementing precautions regarding co-administration with warfarin and liver dysfunction, the estimated mean incidence rate of adverse drug reactions (95% confidence interval) decreased significantly to 0.73 (0.59-0.90) and 0.72 (0.55-0.94), respectively. Accordingly, some of the implementation of safety measures significantly reduced adverse drug reactions. The effectiveness of safety measures implemented during the all-case surveillance of iguratimod was evaluated, revealing that early implementation of safety measures decreased the incidence of adverse drug reactions.

Effectiveness of iguratimod as monotherapy or combined therapy in patients with rheumatoid arthritis: a systematic review and meta-analysis of RCTs

Background

This study aims to evaluate the efficacy and safety of the iguratimod (IGU) as monotherapy or combined therapy in patients with rheumatoid arthritis (RA) by using meta-analysis.

Methods

We searched Medline, EMBASE, Cochrane library, CNKI, Wanfang medical network from initial to 30 June, 2020, for randomized clinical trials (RCTs). Two authors independently screened the studies via reading the title, abstract, and full text. The risk of bias in individual studies was assessed using the Cochrane Risk of Bias tool. STATA 12.0 was used for pooled analysis of all included studies.

Results

A total of 23 RCTs were included in this analysis. Meta-analysis showed that patients in the IGU monotherapy or combined therapy group had significantly higher ACR20 (OR = 1.97, 95% CI 1.29 to 3.00, P = 0.002), lower DAS28-CRP (SMD = −3.49, 95% CI −5.40 to −1.58, P < 0.001) and DAS28-ESR (SMD = −2.61, 95% CI −3.64 to −1.57, P < 0.001), as well as shorter duration of morning stiffness (SMD = −2.06, 95% CI −2.86 to −1.25, P < 0.001) and lower HAQ score (SMD = −0.91, 95% CI −1.61 to −0.21, P = 0.011), than those received other disease-modifying antirheumatic drugs (DMARDs) monotherapy (primarily comprising methotrexate). For the safety profile, IGU monotherapy had similar risks for gastrointestinal reactions (P = 0.070), leucopenia (P = 0.309), increment in transaminase (P = 0.321), increase of ALT (P = 0.051), and liver damage (P = 0.182) to methotrexate monotherapy, and IGU combined with other DMARDs therapy did not increase the risks of these AEs (P > 0.05).

Conclusions

Our evidence suggests that IGU is effective and tolerant as monotherapy or combined therapy especially with methotrexate in patients with active RA. IGU may be regarded as a potential alternative to methotrexate, and a preferable choice when combined with other DMARDs for the treatment of RA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02603-2.

Efficacy and safety of iguratimod combined with methotrexate vs. methotrexate alone in rheumatoid arthritis : A systematic review and meta-analysis of randomized controlled trials

The current systematic review and meta-analysis aims to evaluate the efficacy and safety of iguratimod (IGU) combined with methotrexate (MTX) versus MTX alone in rheumatoid arthritis (RA). Two independent investigators searched for original randomized controlled trials (RCTs) related to the combination of IGU and MTX in RA published before November 1, 2019, in PubMed, Cochrane Library, Embase, the China National Knowledge Infrastructure (CNKI), the Chinese Biomedical Literature Database (CBM), and WanFang Data. Additionally, we searched clinical trial registry websites. We assessed the methodological quality of the included trials using the Cochrane Collaboration tool and the seven-point Jadad scale. Statistical analyses were performed using Review Manager (RevMan) 5.3 (Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014). Meta-regression and publication bias analyses were performed using Stata version 14 software (StataCorp., College Station, TX, USA). A total of 7 RCTs consisting of 665 participants, with 368 participants in the active arm and 297 in the placebo arm, were included in the meta-analysis. The American College of Rheumatology (ACR) value was better in the IGU + MTX group than in the MTX alone group, with a pooled relative risk (RR) for ACR20 (American College of Rheumatology 20% improvement criteria), ACR50, and ACR70 of 1.40 (95% CI, 1.13-1.74), 2.09 (95% CI, 1.67-2.61), and 2.24 (95% CI, 1.53-3.28), respectively. The results of the meta-analysis demonstrated that there was no statistical significance in adverse events (1.06 (95% CI, 0.92-1.23)). The combined treatment is an effective, safe, and economical treatment option for patients who do not respond well to methotrexate alone or for patients who cannot afford expensive biologics that have no confirmed efficacy.

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 treatment in patients with active rheumatoid arthritis in Chinese: A nationwide, prospective real-world study

Background

There is heterogeneity in the clinical manifestations and responses to drugs in RA patients due to variety of factors such as genes and environment. Despite advances in the treatment of rheumatoid arthritis (RA), approximately 40% of RA patients still do not achieve primary clinical outcomes in randomized trials, and its low remission rate and high economic consumption remain unresolved, especially in developing countries. Iguratimod (IGU) is a new disease-modifying anti-rheumatic drug (DMARD) with a low price that has demonstrated good efficacy and safety in clinical trials and was approved for active RA in China and Japan. As the most populous country in the Western Pacific region, it is warranted to conduct a study with a large scale of patients in a real-life setting. Our study confirms the new option for RA patients, which is potentially benificial for public health in developing countries.

Methods

This was a nationwide, prospective real-world study of IGU. Eligible subjects were active adult RA patients who aged 18 to 85 with or without multiple comorbidities such as hypertension and diabetes with DMARDs at a stable dosage for at least 12 weeks, or without ongoing DMARDs. A two-stage design was used for this study. In the first stage (the first 12 weeks), IGU 25 mg bid was added as monotherapy or to the background therapy, and in the second stage (the latter 12 weeks), adjustment of RA medicines other than IGU was allowed according to the participants’ disease activity. The primary endpoints were American College of Rheumatology 20% response (ACR20) 24 weeks and adverse events during 24 weeks. The secondary endpoints were ACR50 and ACR70 over 24 weeks, the changes of DAS28 and Health Assessment Questionnaire (HAQ) at week 12 and week 24 from baseline. The trial was registered with ClinicalTrials.gov, number NCT01554917.

Findings

Between March 2012 and January 2015, 1759 participants were enrolled, of whom 81•5% (1433/1759) completed the study. Notably, 1597 patients in the full analysis set were assessed for the effectiveness and 1751 patients were in the safety analysis set; 71•9% (1148/1597) of the patients achieved the primary endpoint of ACR20 response at week 24, and 51•7% (906/1751) patients had at least 1 adverse event (AE). The incidence of the clinical significant AE (grade≥3) of special interest was 3•4% (54 patients for grade 3 and 6 patients for grade 4), and 0•7% (13/1751) of patients developed SAEs associated with IGU. The most common clinical significant AEs were infection in 0•6% (10/1751) of the patients, abdominal discomfort in 0•5% (9/1751) of the patients including 0•2% (3/1751) gastric ulcer, fracture in 0•4% (7/1751), and increased alanine aminotransferase (ALT) in 0•2% (3/1751) of the patients. The secondary endpoint of ACR50 and ACR70 response rates at week 24 were 47•4% (757/1597) and 24•0% (384/1597). DAS28 was 4•11±1•27 and 3•75±1•32 at week 12 and 24, which was significantly decreased -1•40±1•10 and -1•75±1•26 compared with baseline (P<0•001) respectively. Changes in HAQ at week 12 and 24 from baseline were -7•4 ± 9•18 and -8•5 ± 9•97, respectively (all P<0•001). Stratified analysis results showed that the patients with shorter disease duration, male gender had better response to IGU. There was no significant difference in ACR20/50/70 responses between elderly patients(≥65 years) and younger patients(<65 years), IGU monotherapy or combined with other DMARDs. However, more fractures (1•1% vs 0•5%; P = 0•64) and infections (8•7% vs 7•9%; P = 0•69) were observed in elderly patients in our study.

Interpretation

Our results confirmed the effectiveness and safety of IGU as a new DMARD for active patients with RA as monotherapy or combination therapy.

Funding

This study was supported by “the 11th Five-Year-Plan for Science and Technology Support Program (2012ZX09104-103-01)”.

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.

Acute respiratory viral adverse events during use of antirheumatic disease therapies: A scoping review

INTRODUCTION

COVID-19 is an acute respiratory viral infection that threatens people worldwide, including people with rheumatic disease, although it remains unclear to what extent various antirheumatic disease therapies increase susceptibility to complications of viral respiratory infections.

OBJECTIVE

The present study undertakes a scoping review of available evidence regarding the frequency and severity of acute respiratory viral adverse events related to antirheumatic disease therapies.

METHODS

Online databases were used to identify, since database inception, studies reporting primary data on acute respiratory viral infections in patients utilizing antirheumatic disease therapies. Independent reviewer pairs charted data from eligible studies using a standardized data abstraction tool.

RESULTS

A total of 180 studies were eligible for qualitative analysis. While acknowledging that the extant literature has a lack of specificity in reporting of acute viral infections or complications thereof, the data suggest that use of glucocorticoids, JAK inhibitors (especially high-dose), TNF inhibitors, and anti-IL-17 agents may be associated with an increased frequency of respiratory viral events. Available data suggest no increased frequency or risk of respiratory viral events with NSAIDs, hydroxychloroquine, sulfasalazine, methotrexate, azathioprine, mycophenolate mofetil, cyclophosphamide, or apremilast. One large cohort study demonstrated an association with leflunomide use and increased risk of acute viral respiratory events compared to non-use.

CONCLUSION

This scoping review identified that some medication classes may confer increased risk of acute respiratory viral infections. However, definitive data are lacking and future studies should address this knowledge gap.

Small Molecule Inhibitors in the Treatment of Rheumatoid Arthritis and Beyond: Latest Updates and Potential Strategy for Fighting COVID-19

The development of biological disease-modifying antirheumatic drugs (bDMARDs) and target synthetic DMARDs (tsDMARDs), also known as small molecule inhibitors, represent a breakthrough in rheumatoid arthritis (RA) treatment. The tsDMARDs are a large family of small molecules targeting mostly the several types of kinases, which are essential in downstream signaling of pro-inflammatory molecules. This review highlights current challenges associated with the treatment of RA using small molecule inhibitors targeting intracellular JAKs/MAPKs/NF-κB/SYK-BTK signaling pathways. Indeed, we have provided the latest update on development of small molecule inhibitors, their clinical efficacy and safety as a strategy for RA treatment. On the other hand, we have highlighted the risk and adverse effects of tsDMARDs administration including, among others, infections and thromboembolism. Therefore, performance of blood tests or viral infection screening should be recommended before the tsDMARDs administration. Interestingly, recent events of SARS-CoV-2 outbreak have demonstrated the potential use of small molecule inhibitors not only in RA treatment, but also in fighting COVID-19 via blocking the viral entry, preventing of hyperimmune activation and reducing cytokine storm. Thus, small molecule inhibitors, targeting wide range of pro-inflammatory singling pathways, may find wider implications not only for the management of RA but also in the controlling of COVID-19.

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.

Iguratimod Inhibits the Aggressiveness of Rheumatoid Fibroblast-Like Synoviocytes

Objective

Iguratimod, a novel disease-modifying anti-rheumatic drug for the treatment of rheumatoid arthritis, has been approved in China and Japan. Here, we aimed to find whether iguratimod can inhibit the aggressive behavior and promote apoptosis of rheumatoid fibroblast-like synoviocytes (RA-FLSs).

Methods

The proliferation of RA-FLSs was assessed by 5-ethynyl-2′-deoxyuridine test and Cell Counting Kit-8. Migration and invasion were determined by the wound test and a transwell assay. Apoptosis was tested by flow cytometry. The mRNA expression of matrix metalloproteinases (MMPs) and proinflammatory cytokines in RA-FLSs were measured by quantitative PCR and ELISA. To gain insight into the molecular signaling mechanisms, we determined the effect of iguratimod on the activation of mitogen-activated protein kinases (MAPK) signaling pathways by the cellular thermal shift assay (CETSA) and western blot.

Results

Iguratimod treatment significantly reduced the proliferation, migration, and invasive capacities of RA-FLSs in a dose-dependent manner in vitro. MMP-1, MMP-3, MMP-9, Interleukin-6 (IL-6), and monocyte chemoattractant protein-1 mRNA and protein levels were all decreased after treatment with iguratimod. Furthermore, tumor necrosis factor-alpha- (TNF-α-) induced expression of phosphorylated c-Jun N-terminal kinases (JNK) and P38 MAPK were inhibited by iguratimod. Additionally, iguratimod promoted the apoptosis of RA-FLSs. Most importantly, iguratimod was shown to directly interact with JNK and P38 protein by CETSA assay. Moreover, activating transcription factor 2 (ATF-2), a substrate of both JNK and P38, was suppressed by iguratimod.

Conclusions

Our findings suggested that the therapeutic effects of iguratimod on RA might be, in part, due to targeting the aggressive behavior and apoptosis of RA-FLSs.

Iguratimod: a valuable remedy from the Asia Pacific region for ameliorating autoimmune diseases and protecting bone physiology

Autoimmune diseases are affected by complex pathophysiology involving several cell types, cytokines, antibodies, and mimicking factors. Different drugs are used to ameliorate these autoimmune reactions, including nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, antiantibodies, and small molecular drugs (DMARDs), and they are clinically in vogue for diseases such as rheumatoid arthritis (RA). Nevertheless, low cost-effectiveness, reduced efficacy, adverse effects, and patient nonresponse are unappealing factors driving the development of new drugs such as iguratimod. Iguratimod is primarily used to ameliorate RA in Japanese and Chinese clinics. However, its efficacy against other autoimmune ailments is also under intense investigation, and the number of investigations is becoming increasingly larger with each passing day. The articular structure comprises synovium, ligaments, and bone. The latter is more complex than the others since it regulates blood cells and autoimmunity in addition to providing skeletal support to the body. Therefore, its protection is also of prime importance in RA and other autoimmune diseases. Herein, we have highlighted the role of iguratimod in autoimmune diseases and bone protection. We suggest that iguratimod’s unique mode of action compared with that of other DMARDs and its good patient response makes it a suitable antirheumatic and bone-protecting drug.

T-614 Promotes Osteoblastic Cell Differentiation by Increasing Dlx5 Expression and Regulating the Activation of p38 and NF-κB

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by bone loss. Degree of inflammation has been identified as an important initiator of skeletal damage in RA. Iguratimod (T-614) is an anti-inflammatory agent which has been reported to show the inhibitory effect of bone destruction in RA. However, the role of T-614 in osteoblast differentiation is still not clear. In this study, we intended to find the effect of T-614 on the osteogenesis process. We detected osteogenesis markers and transcription factors associated with osteoblastic lineage and bone formation in the culture of mesenchymal stem cells which differentiate osteoblast. The contents and activity of alkaline phosphatase, levels of collagen type I and bone gla protein, and calcium nodule formation were increased significantly after T-614 treated. Meanwhile, the mRNAs expressions of Osterix and Dlx5 were also found to be increased significantly by real-time PCR. The changes of levels of phosphorylation of p38 and NF-κB were also detected by Western blot. The results showed that T-614 promotes osteoblastic differentiation by increasing the expression of Osterix and Dlx5 and increasing the activation of P38. T-614 could advance the ectopic expression of NF-κB to suppress inflammation, which indirectly inhibits the damage of the osteoblasts.

Anti-allodynic action of the disease-modifying anti-rheumatic drug iguratimod in a rat model of neuropathic pain

OBJECTIVE

Patients with rheumatoid arthritis experience nociceptive as well as neuropathic pain. The effect of iguratimod (IGU), a disease-modifying anti-rheumatic drug, on neuropathic pain in a rat model of chronic constriction injury (CCI) was examined in this study.

METHODS

CCI was induced by making four ligations on the left sciatic nerve. Rats with stable signs of static allodynia were selected 2 weeks after the surgery and drug treatments were started (day 0). The test drugs were orally administered once daily for 15 days. The threshold of mechanical pain response in the hind paw was evaluated by the von Frey hair test in a blinded manner. To observe histological changes in the spinal cord, the L4 region was subjected to immunohistochemical analysis for the detection of microglial cells.

RESULTS

IGU showed an anti-allodynic effect on CCI-induced neuropathic pain at days 6 and 14, but not at 90 min after the first administration of IGU. This effect of IGU was observed until day 21. Furthermore, IGU decreased the number of Iba-1-positive cells, which had been increased at the ipsilateral side of the dorsal horn by CCI.

CONCLUSIONS

These results suggest that IGU suppresses neuropathic pain via a different mechanism from that of current therapeutics.

Iguratimod in combination with methotrexate in active rheumatoid arthritis : Therapeutic effects

BACKGROUND

Rheumatoid arthritis (RA) is a potentially destructive disease that may have a profound impact on patients' function and quality of life. RA therapy is still a challenge for rheumatologists; however, new antirheumatic drugs may be a treatment option for disease-modifying antirheumatic drug (DMARD)-experienced patients with active RA.

OBJECTIVES

The present study is a prospective trial that aims to investigate the effects of therapy with iguratimod plus methotrexate (MTX) in comparison with iguratimod or MTX monotherapy in DMARD-experienced adult patients with active RA.

METHODS

A total of 131 patients (24 men, 107 women, mean age 46.63 ± 10.61 years) with a history of being treated with traditional DMARDs were investigated. In all, 44 patients were treated with iguratimod (25 mg, twice daily, orally) plus MTX (a weekly dose of 10 mg, orally), 38 patients received iguratimod (25 mg, twice daily, orally), or 49 patients received MTX (weekly dose of 10 mg, orally) for 24 weeks.

RESULTS

A therapeutic effect with iguratimod was observed between 4 and 10 weeks after treatment initiation and was effective even in patients who had a poor response to previous treatment with DMARDs. The combination of iguratimod with MTX was superior to iguratimod or MTX monotherapy.

CONCLUSION

The data imply that iguratimod is a welcome addition to the small-molecule drug therapy for DMARD-experienced patients with active RA. Iguratimod (alone or in combination with MTX) is an emerging option for the treatment of DMARD-experienced adult patients with active RA who have had an inadequate response to or are intolerant of other DMARDs.

Effects of iguratimod on the levels of circulating regulators of bone remodeling and bone remodeling markers in patients with rheumatoid arthritis

This study aims to investigate the effect of iguratimod, a novel disease-modifying antirheumatic drug, alone or combined with methotrexate (MTX), on the serum levels of regulators of bone remodeling (receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), and Dickkopf-1 (DKK-1)) and bone remodeling markers (C-telopeptide of type I collagen (CTX-I) and procollagen type I N-terminal propeptide (PINP)) in patients with rheumatoid arthritis (RA). Patients with RA were treated with iguratimod, MTX, or their combination for 12 months. Serum samples were collected before treatment and 6 and 12 months afterwards. RANKL, OPG, DKK-1, CTX-I, and PINP levels were measured, and radiographic progression was assessed. The serum RANKL levels decreased after treatment for 6 and 12 months with iguratimod (median: baseline 565.00 pmol/L vs. 6 months 411.00 pmol/L vs. 12 months 212.00 pmol/L), MTX (median: baseline 562.50 pmol/L vs. 6 months 399.50 pmol/L vs. 12 months 163.50 pmol/L), and their combination (median: baseline 971.00 pmol/L vs. 6 months 272.50 pmol/L vs. 12 months 241.50 pmol/L). Combination therapy showed greater effects 6 months post-treatment compared to single-drug therapy. PINP levels increased significantly 12 months post-treatment with all therapies, but only the combination therapy led to decreased CTX-I levels. OPG and DKK-1 levels showed no significant changes. The three treatments showed no significant differences in radiographic progression. Iguratimod could stimulate bone formation and regulate the RANKL/RANK/OPG system rather than DKK-1levels. Its effects are comparable to those of MTX, and combination therapy showed stronger effects.

Efficacy and safety evaluation of a combination of iguratimod and methotrexate therapy for active rheumatoid arthritis patients: a randomized controlled trial

This study aimed to investigate the efficacy and safety of iguratimod (T-614) in combination with methotrexate (MTX) for active rheumatoid arthritis (RA) patients. Sixty active RA patients were enrolled according to the 2010 American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) classification criteria, and were randomized into MTX + T-614 group and MTX group. T-614 was orally administered at a dosage of 50 mg/day (25 mg twice daily) for 24 weeks. MTX was orally administered to RA patients at a stable weekly dosage of 10 mg/week for the first 4 weeks and subsequent 12.5 mg/week for the later 20 weeks. Clinical features at baseline and efficacy endpoints of the ACR 20 % response (ACR20), ACR50, ACR70, and adverse events at 24 weeks were evaluated, respectively. After 24 weeks of treatment, clinical features at baseline, including counts for tender joints and swelling joints, visual analog scale for pain, patient's and physician's global assessment, erythrocyte sedimentation rate, C-reactive protein, disease activity score 28, health assessment questionnaire, simplified disease activity index, and ACR50 in the MTX + T-614 group, showed statistically significant differences comparing with the MTX group (P < 0.05). There was no significant increase in adverse events in the MTX + T-614 group comparing with the MTX group (P > 0.05). The combination of MTX and T-614 therapy appeared to have a good efficacy and safety for active RA and was superior to MTX-alone therapy after 24 weeks of treatment.

Current immunotherapy in rheumatoid arthritis

Rheumatoid arthritis is a common autoimmune disease primarily manifesting as chronic synovitis, subsequently leading to a change in joint integrity. Progressive disability and systemic complications are strongly associated with a decreased quality of life. To maintain function and health in patients with rheumatoid arthritis, early, aggressive and guided immunosuppressive therapy is required to induce clinical remission. Antirheumatic drugs are capable of controlling synovial inflammation and are therefore named 'disease-modifying antirheumatic drugs' (DMARDs). This article aims to bridge the beginning of DMARD therapy with agents such as methotrexate, leflunomide, sulfasalazine, injectable gold and (hydroxy)chloroquine with biological therapies, and with the new era of kinase inhibitors. Mechanisms of action, as well as advantages and disadvantages of DMARDs, are discussed with respect to the current literature and current recommendations.

Efficacy and safety of iguratimod for the treatment of rheumatoid arthritis

All randomized controlled trials (RCTs) of iguratimod for rheumatoid arthritis (RA) to assess its efficacy and safety are included in this paper. The Review Manager software was used for meta-analysis to assess risk bias of the studies included, and GRADE profiler software was used for the evidence quality of the studies included. Four RCTs involving 1407 patients with RA were included. Meta-analyses showed that, after 24-week therapy, ACR20, tender joint count, swollen joint count, rest pain, physician and patient global assessment of disease activity, HAQ score, ESR, and CRP in iguratimod group were better than those in placebo group and that the difference between those of iguratimod group and those of other DMARDs (MTX and SASP) group was not significant. GRADE evidence classification of the studies included was moderate. Iguratimod for RA had few adverse events, and its efficacy and safety were the same as those of MTX and SASP for RA. The results of this systematic review suggest that more high-quality and large-scaled RCTs were needed to determine the efficacy of iguratimod for RA and whether iguratimod is as effective as other DMARDs besides MTX and SASP.