Efficacy and safety of iguratimod for the treatment of rheumatoid arthritis

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

A review of hyaluronic acid-based therapeutics for the treatment and management of arthritis

Hyaluronic acid (HA), a biodegradable, biocompatible and non-immunogenic therapeutic polymer is a key component of the cartilage extracellular matrix (ECM) and has been widely used to manage two major types of arthritis, osteoarthritis (OA) and rheumatoid arthritis (RA). OA joints are characterized by lower concentrations of depolymerized (low molecular weight) HA, resulting in reduced physiological viscoelasticity, while in RA, the associated immune cells are over-expressed with various cell surface receptors such as CD44. Due to HA's inherent viscoelastic property and its ability to target CD44, there has been a surge of interest in developing HA-based systems to deliver various bioactives (drugs and biologics) and manage arthritis. Considering therapeutic benefits of HA in arthritis management and potential advantages of novel delivery systems, bioactive delivery through HA-based systems is beginning to display improved outcomes over bioactive only treatment. The benefits include enhanced bioactive uptake due to receptor-mediated targeting, prolonged retention of bioactives in the synovium, reduced expressions of proinflammatory mediators, enhanced cartilage regeneration, reduced drug toxicity due to sustained release, and improved and cost-effective treatment. This review provides an underlying rationale to prepare and use HA-based bioactive delivery systems for arthritis applications. With special emphasis given to preclinical/clinical results, this article reviews various bioactive-loaded HA-based particulate carriers (organic and inorganic), gels, scaffolds and polymer-drug conjugates that have been reported to treat and manage OA and RA. Furthermore, the review identifies several key challenges and provides valuable suggestions to address them. Various developments, strategies and suggestions described in this review may guide the formulation scientists to optimize HA-based bioactive delivery systems as an effective approach to manage and treat arthritis effectively.

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).

Signaling pathways in rheumatoid arthritis: implications for targeted therapy

Rheumatoid arthritis (RA) is an incurable systemic autoimmune disease. Disease progression leads to joint deformity and associated loss of function, which significantly impacts the quality of life for sufferers and adds to losses in the labor force. In the past few decades, RA has attracted increased attention from researchers, the abnormal signaling pathways in RA are a very important research field in the diagnosis and treatment of RA, which provides important evidence for understanding this complex disease and developing novel RA-linked intervention targets. The current review intends to provide a comprehensive overview of RA, including a general introduction to the disease, historical events, epidemiology, risk factors, and pathological process, highlight the primary research progress of the disease and various signaling pathways and molecular mechanisms, including genetic factors, epigenetic factors, summarize the most recent developments in identifying novel signaling pathways in RA and new inhibitors for treating RA. therapeutic interventions including approved drugs, clinical drugs, pre-clinical drugs, and cutting-edge therapeutic technologies. These developments will hopefully drive progress in new strategically targeted therapies and hope to provide novel ideas for RA treatment options in the future.

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

A Systematic Review and Meta-Analysis of 19 Randomized Controlled Trials of Iguratimod Combined With Other Therapies for Sjogren’s Syndrome

Objective

To explore the efficacy and safety of Iguratimod intervention in Primary Sjogren’s syndrome (pSS).

Methods

Many databases were searched to collect the RCTs. Three independent reviewers extracted data and assessed the quality of the studies based on the Cochrane Handbook. The statistical analysis was done by RevMan 5.3 and STATA. The quality of evidence was evaluated by GRADE tool.

Results

Twenty-nine RCTs with 2258 participants were included in this review. The meta-analysis shows that: iguratimod experiment group can reduce the ESSPRI score (WMD -1.93 [-2.33, -1.52], P&lt;0.00001), ESSDAI score (WMD -1.39 [-1.81, -0.98], P&lt;0.00001), Schirmer’s test (WMD 1.77 [0.85, 2.70], P=0.0002), RF (WMD -5.78 [-7.59, -3.97], P&lt;0.00001), and decrease the ESR level (WMD -7.05 [-9.84, -4.26], P&lt;0.00001). Meanwhile, the summary result showed the addiction of Iguratimod may not increase the adverse events. The adverse events were mainly gastrointestinal discomfort, abnormal liver function, and rash and itching. The quality of evidence of adverse events was moderate. Referring to minimal clinically important difference (MCID), the improvement of ESSPRI is clinically significant, and the improvement of ESSDAI for patients older than 60 years old may be clinically significant.

Conclusion

Based on current evidence, iguratimod can effectively reduce ESSPRI score, ESSDAI score, Schirmer’s test score and decrease systemic inflammatory response (such as ESR level and RF level) without increasing the probability of adverse events. The recommended course of treatment is at least 12 weeks.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?, identifier CRD42020220770.

Iguratimod promotes transformation of mononuclear macrophages in elderly patients with rheumatoid arthritis by nuclear factor-κB pathway

BACKGROUND

The role of macrophages in rheumatoid arthritis (RA) and its mechanism have attracted much attention in RA pathogenesis. Macrophages accumulate in the synoviums of RA, and the proportion of M1 type pro-inflammatory macrophages is higher than that of M2 type anti-inflammatory macrophages, leading to the secretion of inflammatory molecules and the aggravation of inflammatory reaction, which has made macrophages a potential target of RA drugs. Iguratimod is a kind of cyclo-oxygenase-2 inhibitor that affects macrophage polarity. It is speculated that its anti-inflammatory and anti-rheumatic effects may be related to the regulation of macrophage M1/M2 ratio.

AIM

To investigate the effects of Iguratimod on the polarity of mononuclear macrophages in elderly patients with RA.

METHODS

Elderly patients with RA and joint effusion were selected, including 10 men and 25 women, with an average age of 66.37 ± 4.42 years. Patients were treated with oral administration of 25 mg Iguratimod (Iremod, State Food and Drug Administration Approval No. H20110084) twice daily for 12 wk. Disease Activity Score 28 and Health Assessment Questionnaire score were collected according to the disease severity before and after treatment. Venous blood and joint effusion fluid were collected, mononuclear macrophages were extracted and expression of cell surface markers CD86, CD64, CD163, and CD206 was analyzed by flow cytometry. The concentration of inflammatory factors interleukin (IL)-6, IL-1β, transforming growth factor-β, and IL-4 in the joint effusion fluid was analyzed by enzyme-linked immunosorbent assay. Expression of mononuclear cells inhibitor of nuclear factor-κB (IκB) and phosphorylated IκB in peripheral blood was analyzed by western blotting.

RESULTS

Disease Activity Score 28 score and Health Assessment Questionnaire score of patients treated with Iguratimod decreased significantly. The percentage of cell surface markers CD86 and CD64 decreased significantly, and the percentage of CD163 and CD206 increased significantly (P < 0.05). The inflammatory factors IL-6 and IL-1β decreased significantly, and transforming growth factor-β and IL-4 increased significantly. Western blot analysis showed that mononuclear cell inhibitor of nuclear factor-κB in peripheral blood was significantly increased after treatment, and its phosphorylation level was significantly decreased (P < 0.05).

CONCLUSION

Iguratimod can promote the transformation of mononuclear macrophages from M1 to M2 in elderly patients with RA by inhibiting the nuclear factor-κB pathway, thus improving symptoms 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)”.

2018 Chinese Guidelines for the Diagnosis and Treatment of Rheumatoid Arthritis

A multidisciplinary guideline development group was established to formulate this evidence-based diagnosis and treatment guidelines for rheumatoid arthritis (RA) in China. The grading of recommendations, assessment, development, and evaluation (GRADE) system was used to rate the quality of the evidence and the strength of recommendations, which were derived from research articles and guided by the analysis of the benefits and harms as well as patients' values and preferences. A total of 10 recommendations for the diagnosis and treatment of RA were developed. This new guideline covered the classification criteria, disease activity assessment and monitoring, and the role of disease modifying antirheumatic drugs (DMARDs), biologics, small molecule synthetic targeting drugs, and glucocorticoids in the treat-to-target approach of RA. This guideline is intended to serve as a tool for clinicians and patients to implement decision-making strategies and improve the practices of RA management in China.

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.

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.

Iguratimod (T-614) attenuates severe acute pancreatitis by inhibiting the NLRP3 inflammasome and NF-κB pathway

Severe acute pancreatitis (SAP) is an acute abdominal disease that can develop locally to the multiple organs. It is characterized by pancreatic tissue self-digestion, and the rapid release of inflammatory cytokines, which play a dominant role in local or even systemic inflammation. In this study, we investigate the protective effect of T-614 against SAP induced by cerulein plus LPS in mice. Biochemical markers associated with pancreatitis in serum such as inflammatory cytokines, amylase and lipase activities were measured. Related proteins of NLRP3 inflammasome and NF-κB signaling pathway were evaluated by western blotting. Hematoxylin-eosin staining (HE) and immunohistochemistry (IHC) were used to evaluate changes of inflammation in pancreatic tissue. T-614 significantly alleviated the elevation markers of pancreatitis and suppresses the pancreatic tissue damage, including histopathological and molecular manifestations. In conclusion, T-614 plays a protective role in experimental SAP mice model via anti-inflammatory effects.

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.

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.

Regulatory Effect of Iguratimod on the Balance of Th Subsets and Inhibition of Inflammatory Cytokines in Patients with Rheumatoid Arthritis

OBJECTIVE

To expand upon the role of iguratimod (T-614) in the treatment of rheumatoid arthritis (RA), we investigated whether the Th1, Th17, follicular helper T cells (Tfh), and regulatory T cells (Treg) imbalance could be reversed by iguratimod and the clinical implications of this reversal.

METHODS

In this trial, 74 patients were randomized into iguratimod-treated (group A) and control (broup B) group for a 24-week treatment period. In the subsequent 28 weeks, both groups were given iguratimod. Frequencies of Th1, Th17, Tfh, and Treg were quantified using flow cytometry, and serum cytokines were detected by enzyme-linked immunosorbent assay. mRNA expression of cytokines and transcriptional factor were quantified by RT-PCR. The composite Disease Activity Score, erythrocyte sedimentation rate, and C-reactive protein were assessed at each visit.

RESULT

The clinical scores demonstrated effective suppression of disease after treatment with iguratimod. In addition, iguratimod downregulated Th1, Th17-type response and upregulated Treg. Furthermore, the levels of Th1, Th17, and Tfh associated inflammatory cytokines and transcription factors were reduced after treatment with iguratimod, while the levels of Treg associated cytokines and transcription factors were increased.

The IL-23-IL-17 axis in inflammatory arthritis

The discovery that the IL-23-IL-17 immune pathway is involved in many models of autoimmune disease has changed the concept of the role of T-helper cell subsets in the development of autoimmunity. In addition to TH17 cells, IL-17 is also produced by other T cell subsets and innate immune cells; which of these IL-17-producing cells have a role in tissue inflammation, and the timing, location and nature of their role(s), is incompletely understood. The current view is that innate and adaptive immune cells expressing the IL-23 receptor become pathogenic after exposure to IL-23, but further investigation into the role of IL-23 and IL-17 at different stages in the development and progression of chronic (destructive) inflammatory diseases is needed. Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are the two most common forms of chronic immune-mediated inflammatory arthritis, and the IL-23-IL-17 axis is thought to have a critical role in both. This Review discusses the basic mechanisms of these cytokines in RA and SpA on the basis of findings from disease-specific animal models as well as human ex vivo studies. Promising therapeutic applications to modulate this immune pathway are in development or have already been approved. Blockade of IL-17 and/or TH17-cell activity in combination with anti-TNF therapy might be a successful approach to achieving stable remission or even prevention of chronic immune-mediated inflammatory diseases.