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

Transdermal delivery of iguratimod and colchicine ethosome by dissolving microneedle patch for the treatment of recurrent gout

This study introduces a novel approach of repetitive modeling to simulate the pathological process of recurrent gout attacks in humans. This methodology addresses the instability issues present in rat models of gout, providing a more accurate representation of the damage recurrent gout episodes inflict on human skeletal systems. A soluble nanoneedle system encapsulating colchicine and iguratimod ethosomal formulations was developed. This system aims to modulate inflammatory cytokines and inhibit osteoclast activity, thereby treating inflammatory pain and bone damage associated with recurrent gout. Additionally, a comprehensive evaluation of the microneedles' appearance, morphology, mechanical properties, and penetration capability confirmed their effectiveness in penetrating the stratum corneum. Dissolution tests and skin irritation assessments demonstrated that these microneedles dissolve rapidly without irritating the skin. In vitro permeation studies indicated that transdermal drug delivery via these microneedles is more efficient and incurs lower drug loss compared to traditional topical applications. In vivo pharmacodynamic assessments conducted in animal models revealed significant analgesic and anti-inflammatory effects when both types of microneedles were used together. Further analyses, including X-ray imaging, hematoxylin and eosin (H&E) staining, Safranin-O/fast green staining, tartrate-resistant acid phosphatase staining, and quantification of osteoclasts, confirmed the bone-protective effects of the microneedle combination. In conclusion, the findings of this research underscore the potential of this novel therapeutic approach for clinical application in the treatment of recurrent gout.

The clinical characteristics and prognosis of patients with SAPHO syndrome--a real-world cohort study

OBJECTIVES

We aimed to analyze the clinical characteristics and outcomes of patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome.

METHODS

The clinical records of 64 patients with SAPHO syndrome were collected, and the treatment and outcomes of 27 patients were followed up. The patients were divided into three groups according to the site of bone lesions: only anterior chest wall (ACW) involvement, only spinal involvement, and bone lesion involvement at both sites. The clinical characteristics and outcomes were compared. The clinical characteristics of the patients with and without peripheral joint involvement were compared.

RESULTS

Among all patients, 31.25% (20/64) had only ACW involvement, 15.63% (10/64) had only spinal involvement, and 53.12% (34/64) had both ACW and spinal involvement. Peripheral joint involvement was observed in 25.00% (16/64) of the patients. Patients with only spinal involvement were older than those with only ACW involvement (p = 0.006). Patients with both ACW and spinal involvement were older than those with only ACW involvement (p = 0.002) and had a longer diagnosis delay (p = 0.015). Patients with peripheral joint involvement were younger than those without peripheral joint involvement (p = 0.028). During follow-up, 88.89% (24/27) of patients had good outcomes. Twenty-two patients were treated with non-steroidal anti-inflammatory drugs + Iguratimod (IGU), and the outcomes of 90.91% (20/22) improved.

CONCLUSIONS

A relationship may exist between the sites of bone lesions and clinical characteristics of patients with SAPHO syndrome. The clinical outcomes of these patients may be good, and IGU may be effective in treating SAPHO syndrome. Key Points • This study is the first long-term follow-up on the effectiveness of iguratimod in treating patients with SAPHO. • This study revealed that patients with SAPHO and different bone lesion sites may present with different clinical characteristics.

A novel drug combination of Tofacitinib and Iguratimod alleviates rheumatoid arthritis and secondary osteoporosis

BACKGROUND

The inadequate response of some patients with rheumatoid arthritis (RA) to current therapies is an issue that needs to be addressed. Patients with refractory RA (RRA) are often accompanied by high Tumor necrosis factor (TNF) expression. We evaluated the synergistic therapeutic effects of the combination of Iguratimod (IGU) and Tofacitinib (TOF) on RRA and secondary osteoporosis.

METHODS

Pathological changes in the ankle joints of collagen-induced arthritis (CIA) + TNF model rats were assessed using hematoxylin and eosin (HE) staining. Immunohistochemistry (IHC) and immunofluorescence (IF) were used to evaluate pyroptosis-related protein levels in the synovial tissues. Moreover, the knee joint was investigated by performing HE staining, IHC, and micro-computed tomography. Furthermore, in vitro, western blotting and enzyme-linked immunosorbent assay (ELISA) were performed to detect the effects of TOF and IGU on TNF-α-induced pyroptosis in fibroblast-like synoviocytes of RA.

RESULTS

After treatment with TOF and/or IGU, the arthritis scores, inflammatory cell infiltration in synovial tissues, and levels of interleukin (IL)-18, IL-1β, and IL-6 in the plasma were remarkably increased in the CIA + TNF model and dramatically decreased in the combination group. The expression of pyroptosis-related proteins was significantly lower in the combination group than in the CIA + TNF group, and a consistent trend was observed in vitro. Bone destruction was significantly alleviated, and the bone turnover rate was remarkably increased in the combination group compared to that in the CIA + TNF model.

CONCLUSION

TOF + IGU alleviated the severity of RRA in the CIA + TNF rat model, relieving joint inflammation, reducing bone erosion, and suppressing pyroptosis. The combined application of TOF and IGU may have a superimposed therapeutic effect on RRA and secondary osteoporotic bone remodeling.

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.

Efficacy and safety of Iguratimod in the treatment of Ankylosing Spondylitis: A systematic review and meta-analysis of randomized controlled trials

Objective

To explore the efficacy and safety of Iguratimod (IGU) intervention in the treatment of Ankylosing Spondylitis (AS).

Methods

We used computer to search literature databases, collected randomized controlled trials (RCTs) related to IGU treatment of AS, and searched the relevant literature in each database until Sep. 2022. Two researchers independently carried out literature screening, data extraction, and evaluation and analysis of the risk of bias in the included studies, and then used Rev Man5.3 software for meta-analysis. The protocol is CRD42020220798.

Results

A total of 10 RCTs involves in 622 patients were collected. The statistical analysis showed that IGU can decrease the BASDAI score (SMD -1.62 [-2.20, -1.05], P<0.00001. Quality of evidence: low), the BASFI score (WMD -1.30 [-1.48, -1.12], P<0.00001. Quality of evidence: low) and the VAS (WMD -2.01 [-2.83, -1.19], P<0.00001. Quality of evidence: very low). Meanwhile, the addition of IGU into the conventional therapy would not increase the adverse events (RR 0.65 [0.43, 0.98], P=0.04. Quality of evidence: moderate).

Conclusion

IGU may be an effective and safe intervention for AS.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?, identifier CRD42020220798.

Iguratimod decreases bleomycin-induced pulmonary fibrosis in association with inhibition of TNF-α in mice

Severe interstitial lung disease secondary to connective tissue diseases, characterized by pulmonary inflammation and fibrosis, often have very poor prognosis due to lack of effective treatments. Iguratimod (IGU) shows encouraging efficacy in treating connective tissue diseases, however, the underlying mechanism is still to be elucidated. In this study, we investigated the impact of IGU on bleomycin-induced interstitial lung disease and the related tumor necrosis factor-α (TNF-α) signaling pathway in mice and in the alveolar epithelial cell A549. We found IGU decreased pulmonary inflammation and fibrosis and expression of fibrosis-related genes such as Collagen I, α-smooth muscle actin (α-SMA) and matrix metalloproteinase-2 (MMP-2) induced by bleomycin. IGU inhibited epithelial-mesenchymal transition as evidenced by decreased E-cadherin expression but increased vimentin expression. IGU reduced TNF-α production in the pulmonary fibrosis murine model and in the in vitro cultured A549 cells. Furthermore, IGU ameliorated TNF-α-induced severe pulmonary fibrosis and inhibited TNF-α-induced activation of NF-κB. In addition, IGU decreased IL-6 production and phosphorylation of STAT3. In conclusion, the IGU-mediated anti-fibrogenesis effect was associated with the inhibition of TNF-α and NF-κB.

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.

Effects of iguratimod on glucocorticoid-induced disorder of bone metabolism in vitro

INTRODUCTION

Glucocorticoids are widely used to treat various diseases including rheumatoid arthritis (RA); however, one of the most frequent and severe adverse effects is glucocorticoid-induced osteoporosis (GIOP). Iguratimod (IGU) is a novel conventional synthetic disease-modifying anti-rheumatic drug developed in Japan. The aim of this study is to investigate the effects of IGU on glucocorticoid-induced disorder of bone metabolism in vitro.

MATERIALS AND METHODS

In osteoclastogenesis of mouse bone marrow-derived cells, tartrate-resistant acid phosphatase staining, resorption pit assay, western blotting, real-time polymerase chain reaction (PCR), and mRNA sequencing were performed. In osteoblastogenesis of MC3T3-E1 cells, alkaline phosphatase (ALP) staining and activity, alizarin red staining, and mRNA sequencing were performed, and real-time PCR and western blotting were conducted in MC3T3-E1 cells and murine osteocyte-like cell line MLO-Y4 cells.

RESULTS

IGU significantly suppressed a dexamethasone-induced increase in osteoclasts, differentiation, and bone resorption activity by inhibition of the receptor activator of the nuclear factor kappa-B (RANK)/tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6)/nuclear factor kappa-B (NFκB)-p52 pathway. In MC3T3-E1 cells, IGU significantly upregulated dexamethasone-induced downregulation of ALP activity, bone mineralization, and osteoblast-related gene and protein expression. In MLO-Y4 cells, IGU significantly upregulated dexamethasone-induced downregulation of the gene expression of ALP and osteocalcin, and also downregulated receptor activator of NFκB ligand (RANKL)/osteoprotegerin gene expression ratio without dexamethasone.

CONCLUSION

These results suggest that IGU may improve glucocorticoid-induced disorder of bone metabolism and may exhibit positive effects against GIOP associated with RA.

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.

Iguratimod combination therapy compared with methotrexate monotherapy for the treatment of rheumatoid arthritis: a systematic review and meta-analysis

OBJECTIVE

We estimated the relative efficacy and safety of iguratimod combination therapy compared with methotrexate monotherapy for the treatment of rheumatoid arthritis.

METHOD

We identified parallel randomized controlled trials from the Cochrane Central Register of Controlled Trials in The Cochrane Library (CENTRAL), MEDLINE, Embase, and other databases and trial registries for January April 2020. Independent assessment of the risk of bias and grading of the certainty of evidence was performed for the selected trials. We operated RevMan 5 software to compute the meta-analysis. We applied the random-effects model. The statistical methods applied were the Mantel-Haenszel method and the inverse-variance method for dichotomous and continuous outcomes, respectively.

RESULTS

We included 12 trials involving 1095 participants. Based on our result, patients on iguratimod combination are likely to have 3.53 (95% CI 2.22 to 5.60, moderate-certainty), 3.24, and 2.73 times higher odds for attaining American College of Rheumatology criteria (ACR) 20, 50, and 70, respectively, than methotrexate monotherapy. Disease state measured using DAS28 score (MD -0.71 score, 95% CI -1.03 to -0.39, very low certainty) and functional ability indicated by HAQ (Health Assessment Questionnaire) (MD -0.23, 95% CI -0.34 to -0.11, very low certainty) may also be better. The combination therapy also produced better results for C-reactive protein, erythrocyte sedimentation rate, pain intensity, and patient's and physician's global assessment of disease state. Incidence of adverse events were similar between the groups (OR 1.30, 95% CI 0.92 to 1.83, moderate-certainty).

CONCLUSION

Iguratimod combined with methotrexate may be considered a promising alternative for treating RA. Key Points • Iguratimod combination therapy produced better results in all the efficacy outcomes than methotrexate monotherapy. • Iguratimod combination therapy may be as safe as methotrexate monotherapy. • We recommend future clinical trials of iguratimod combination therapy in RA with iguratimod combined with DMARDs other than methotrexate and conducted in diverse population.

Iguratimod reduces B-cell secretion of immunoglobulin to play a protective role in interstitial lung disease

OBJECTIVE

Our study aimed to investigate the effect of Iguratimod (IGU) on bleomycin (BLM)-induced interstitial lung disease (ILD).

METHODS

The pulmonary fibrosis model group mice were developed by intratracheal injection of BLM. Mice were divided into two groups at random: (1) Control group (BLM group) - endotracheal BLM (BLM, 3.5 mg/kg, Kayaku, Japan) plus an intraperitoneal injection of normal saline, and (2) BLM + IGU group - intratracheal BLM (same as the control group) + IGU intraperitoneal injection (50 mg/kg/d). The alveolar lavage fluid, histopathology/immunohistochemistry, imaging, and other tests were performed on days 7, 14, 21, and 28 after injection.

RESULTS

Lung function, including Compliance (Crs),Tissue damping (G), Static compliance (Cst), Inspiratory capacity (IC), Elastance (Ers), Tissue elastance (H) and Respiratory system resistance (Rrs) in mice, was improved by IGU. IGU reduced BLM-induced changes in pulmonary fibrosis and pulmonary inflammation, as shown in histological examination.Collagen production and inflammatory damage in the lungs caused by BLM were also reduced by IGU. IGU reduced the expression of immunoglobulin IgG and type I collagen in BLM-induced pulmonary fibrosis mice by inhibiting the production of B cells and immunoglobulin, and also delayed the deterioration of imaging changes.

CONCLUSION

IGU inhibits immunoglobulin secretion by B cells to relieve pulmonary inflammation and fibrosis. IGU also plays a protective role in the lung in ILD.

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.

Clinical effectiveness of iguratimod based on real-world data of patients with rheumatoid arthritis

OBJECTIVES

Iguratimod (IGU) is a conventional synthetic disease-modifying drug that has been approved based on its additive effects with methotrexate (MTX) for the treatment of rheumatoid arthritis (RA). The objective of the study is to establish the effectiveness of IGU with versus IGU without MTX irrespective of whether MTX is well tolerated or not by the patients.

METHODS

Disease activity scores in 177 RA patients treated using IGU were retrospectively evaluated at baseline and after 4, 12, and 24 weeks, and adverse events (AEs) were noted.

RESULTS

IGU reduced the disease activity parameters, disease activity score (DAS)-ESR, DAS-CRP, the simplified disease activity index (SDAI), and clinical disease activity index (CDAI) in the concomitant MTX and non-MTX, female and male, and young and elderly patient groups after 24 weeks. Multivariate analysis demonstrated that IGU was more effective with concomitant MTX and in elderly and male patients. Severe AEs were observed only in the elderly group: two cases of pneumonia, 1 of pneumocystis pneumonia, 1 of heart failure, and 1 of salivary gland adenoma.

CONCLUSIONS

IGU is effective for RA, especially with concomitant MTX, and in elderly and male patients. Key Points • Iguratimod is effective for RA, especially with concomitant MTX, and in elderly and male patients. • Since all serious adverse events were in the elderly group in this study, sufficient monitoring for adverse events, especially for elderly RA patients, is needed during iguratimod therapy.

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.

Relative efficacy and safety of iguratimod monotherapy for the treatment of patients with rheumatoid arthritis: a systematic review and meta-analysis

OBJECTIVES

This study aims to compare the efficacy and the safety of the iguratimod with placebo and other disease-modifying antirheumatic drugs (DMARDs) in adults with rheumatoid arthritis.

METHODS

Two authors independently searched and selected randomized controlled trials from Cochrane library, Medline (through Pubmed), and Chinese databases, and then assessed the risk of bias (using ROB 2 tool), and graded the certainty of evidence (using the GRADEpro GDT software). We applied the RevMan 5 software for performing meta-analyses of the final consensus data.

RESULTS

We identified 12 trials involving 1938 participants. Ten trials had an overall high risk of bias. Although iguratimod had superior efficacy than placebo, the incidence of adverse events was also higher. Inferring to non-inferiority analysis with other DMARD therapy (primarily comprising methotrexate), iguratimod is likely to result in similar treatment response (20% (OR 1.04, 95% CI 0.79 to 1.36), 50% and 70% improvement in American College of Rheumatology criteria) and functional ability at 24 weeks. Although the disease state was slightly better with iguratimod (MD - 0.55, 95% CI - 0.85 to - 0.25), a clinically important improvement was not achieved. Iguratimod may have lower C-reactive protein and erythrocyte sedimentation rate values. Swollen joint count, tender joint count, pain intensity, and patient's and physician's global assessment of disease state may be comparable between the therapies. Both the therapies are likely to have similar odds (OR 0.91, 95% CI 0.67 to 1.26) of adverse events.

CONCLUSION

Our evidence suggests that iguratimod may be considered a potential alternative to methotrexate to treat rheumatoid arthritis.Key Points• The Asia Pacific League of Association for Rheumatology (APLAR) has recommended that iguratimod may be used a first-line drug for rheumatoid arthritis in specific cases.• Patients on iguratimod may have similar treatment response, functional ability, disease state, and adverse event profile at 24 weeks compared with those on methotrexate.• Iguratimod may be considered a better alternative to methotrexate in RA patients having high CRP and ESR values.• Future clinical trials in diverse population comparing the efficacy and safety of iguratimod in monotherapy or combination therapy with DMARDs (other than methotrexate) are warranted.

Molecular mechanisms and clinical application of Iguratimod: A review

Iguratimod (IGU) is a novel small-molecule anti-rheumatic drug with remarkable effectiveness and good safety for the treatment of active rheumatoid arthritis. Its mechanism of action is related to its ability to act simultaneously on T and B lymphocytes. IGU can effectively inhibit expression of various inflammatory factors, inhibit B cells from producing immunoglobulins and autoantibodies, downregulate T-cell-mediated cellular immunity, accelerate bone formation, and exert some activity against anti-pulmonary fibrosis. In recent years, IGU has been gradually applied to the treatment of a variety of rheumatic diseases, such as Sjögren's syndrome, ankylosing spondylitis and systemic lupus erythematosus. This article reviews the mechanism of action and clinical research status of IGU, and provides reference for future research on its mechanism of action and clinical application.