Safety and effectiveness of 24-week treatment with iguratimod, a new oral disease-modifying antirheumatic drug, for patients with rheumatoid arthritis: interim analysis of a post-marketing surveillance study of 2679 patients in Japan

Clinical and immunological effects of hydroxychloroquine in patients with active rheumatoid arthritis despite antirheumatic treatment

OBJECTIVES

To investigate the efficacy and safety of hydroxychloroquine (HCQ) in patients with rheumatoid arthritis (RA).

METHODS

Patients with active RA, despite conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), were recruited. HCQ was administered for 24 weeks, in addition to prior treatment. The primary end-point was the proportion of patients achieving American College of Rheumatology (ACR) 20 at Week 24, compared to that of a propensity score-matched historical control group.

RESULTS

Sixty patients were enrolled and administered HCQ. We also identified 276 patients as candidates for the historical control group. Propensity score matching yielded 46 patients in each group. The proportion of patients achieving ACR20 at Week 24 was significantly higher in the HCQ group than in the control group (54.4% vs. 28.3%, P = .007). The proportion of patients achieving ACR50 and ACR70 at Week 24 were also higher in the HCQ group than in the control group (ACR50, 30.4% vs. 4.3%, P = .006; ACR70, 17.4% vs. 0%, P = .005). Neither HCQ retinopathy nor any new safety signal was observed during the study.

CONCLUSION

The addition of HCQ to csDMARDs was effective, with no new safety signal in patients with RA.

Network-Based In Silico Analysis of New Combinations of Modern Drug Targets with Methotrexate for Response-Based Treatment of Rheumatoid Arthritis

BACKGROUND

Methotrexate (MTX), sulfonamides, hydroxychloroquine, and leflunomide have consistently resulted in remission with relatively mild to moderate adverse effects in patients with rheumatoid arthritis (RA). Modern medications outperform traditional treatments in that they target the pathological processes that underlie the development of RA.

METHODS

Following PRISMA guidelines, the authors accomplished a systematic review of the clinical efficacy of RA drugs, including the biologics such as Tumor Necrosis Factor-alpha inhibitors (TNF-α i) like Etanercept, Infliximab, Golimumab, and Adalimumab, kinase inhibitors (JAK inhibitors including Baricitinib and Tofacitanib), SyK inhibitors like Fos-tamatinib, MAPK inhibitors such as Talmapimod, T-cell inhibitors (Abatacept), IL6 blockers (Tocilizumab), and B cells depleters (Rituximab). These drugs have been found to increase remission rates when combined with MTX. A bioinformatics-based network was designed applying STRING-MODEL and the DrugBank database for the aforementioned drugs and MTX and, finally, employed for this systematic review.

RESULTS

Current research demonstrates that non-TNF-α inhibitor biologicals are particularly helpful in treating patients who did not respond well to conventional medications and TNF-α inhibitors. Despite being effective, these innovative drugs have a higher chance of producing hazardous side effects. The in silico investigations suggested an uncovered molecular interaction in combining MTX with other biological drugs. The STRING-MODEL showed that DHFR, TYMS, and ATIC, as the receptors of MTX, interact with each other but are not connected to the major interacted receptors.

CONCLUSIONS

New game-changing drugs including Mavrilimumab, Iguratimod, Upadacitinib, Fenebrutinib, and nanoparticles may be crucial in controlling symptoms in poorly managed RA patients. Emerging therapeutic targets like Toll-like 4 receptors, NLRP3 inflammasome complexes, and mesenchymal stem cells can further transform RA therapy.

Trends in the Epidemiology of Pneumocystis Pneumonia in Immunocompromised Patients without HIV Infection

The increasing morbidity and mortality of life-threatening Pneumocystis pneumonia (PCP) in immunocompromised people poses a global concern, prompting the World Health Organization to list it as one of the 19 priority invasive fungal diseases, calling for increased research and public health action. In response to this initiative, we provide this review on the epidemiology of PCP in non-HIV patients with various immunodeficient conditions, including the use of immunosuppressive agents, cancer therapies, solid organ and stem cell transplantation, autoimmune and inflammatory diseases, inherited or primary immunodeficiencies, and COVID-19. Special attention is given to the molecular epidemiology of PCP outbreaks in solid organ transplant recipients; the risk of PCP associated with the increasing use of immunodepleting monoclonal antibodies and a wide range of genetic defects causing primary immunodeficiency; the trend of concurrent infection of PCP in COVID-19; the prevalence of colonization; and the rising evidence supporting de novo infection rather than reactivation of latent infection in the pathogenesis of PCP. Additionally, we provide a concise discussion of the varying effects of different immunodeficient conditions on distinct components of the immune system. The objective of this review is to increase awareness and knowledge of PCP in non-HIV patients, thereby improving the early identification and treatment of patients susceptible to PCP.

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

Objectives

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

Methods

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

Results

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

Conclusion

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

Macrophages and glial cells: Innate immune drivers of inflammatory arthritic pain perception from peripheral joints to the central nervous system

Millions of people suffer from arthritis worldwide, consistently struggling with daily activities due to debilitating pain evoked by this disease. Perhaps the most intensively investigated type of inflammatory arthritis is rheumatoid arthritis (RA), where, despite considerable advances in research and clinical management, gaps regarding the neuroimmune interactions that guide inflammation and chronic pain in this disease remain to be clarified. The pain and inflammation associated with arthritis are not isolated to the joints, and inflammatory mechanisms induced by different immune and glial cells in other tissues may affect the development of chronic pain that results from the disease. This review aims to provide an overview of the state-of-the-art research on the roles that innate immune, and glial cells play in the onset and maintenance of arthritis-associated pain, reviewing nociceptive pathways from the joint through the dorsal root ganglion, spinal circuits, and different structures in the brain. We will focus on the cellular mechanisms related to neuroinflammation and pain, and treatments targeting these mechanisms from the periphery and the CNS. A comprehensive understanding of the role these cells play in peripheral inflammation and initiation of pain and the central pathways in the spinal cord and brain will facilitate identifying new targets and pathways to aide in developing therapeutic strategies to treat joint pain associated with RA.

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

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

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

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.

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.

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.

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.

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.

Factors influencing physician decisions to discontinue treatment after onset of liver dysfunction: Post-hoc analysis of an all-case post-marketing surveillance study of iguratimod

Objectives: Adverse drug reactions (ADRs) related to liver dysfunction are a common problem in patients with rheumatoid arthritis (RA) receiving iguratimod, but which patient subgroups go on to discontinue iguratimod treatment is unclear. A post-hoc analysis of a post-marketing surveillance study was performed to investigate factors influencing treatment continuation after the onset of liver dysfunction.Methods: Types of ADR were compared between patients in whom iguratimod treatment was discontinued or continued in accordance with the judgment of the patient's physician after the patient developed liver dysfunction as an ADR. Stepwise logistic regression analysis was also conducted to investigate factors associated with treatment discontinuation.Results: The multivariate analysis found that concomitant use of methotrexate (MTX) at >8 mg/week (vs. no use) was associated with a significantly lower risk of discontinuation (OR: 0.136; 95%CI: 0.030-0.620), and previous treatment with MTX (vs. no use) was associated with a significantly higher discontinuation risk (OR: 4.045; 95%CI: 1.098-14.908).Conclusion: Although concomitant use of MTX during iguratimod treatment does not appear to influence treatment discontinuation due to abnormal liver function, liver function tests are of importance to continued treatment in patients receiving iguratimod who have a history of MTX use.

Investigation of the predictors of the response to Iguratimod therapy: A post-hoc analysis of post-marketing surveillance study

Objectives: The treatment response according to patient disease activity during Iguratimod therapy for rheumatoid arthritis has not been sufficiently assessed. A post-hoc analysis of post-marketing surveillance was performed. The treatment effect was evaluated using the European League against Rheumatism (EULAR) response criteria.Methods: Disease Activity Score (DAS) 28 was assessed at various time points. Patients showing a moderate or good response according to the EULAR response criteria at 24 weeks after the start of Iguratimod therapy were considered Responders. Propensity score matching was also performed, after which the factors with the greatest effect on the treatment evaluation were investigated.Results: The mean DAS28 at the start of administration and after 24 weeks was 4.31 and 2.52, respectively, in the Responder and 3.48 and 3.48, respectively, in the Non-responder. After propensity score matching for patient characteristics, the primary factors found to be related to being a Responder were concomitant use of methotrexate (MTX) with Iguratimod, and prior treatment with MTX before the start of Iguratimod.Conclusion: As factors related to the treatment effect, the concomitant use of MTX may contribute to achieving a better effect, and this study has shown that real-world are consistent with the results of clinical trials.

Iguratimod represses B cell terminal differentiation linked with the inhibition of PKC/EGR1 axis

Background

This study aimed to explore the molecular mechanism and clinical relevance of iguratimod in the regulation of human B cell terminal differentiation.

Methods

An in vitro human antibody-secreting cell (ASC) differentiation system was established to test the effect of iguratimod. B cell phenotype and key transcription factors (TFs) relevant to ASC differentiation were analyzed through flow cytometry and qPCR. The COX-2 activity was measured by enzyme immunoassay (EIA). RNA sequencing was used to identify potential targets of iguratimod. We enrolled six treatment-naive rheumatoid arthritis (RA) patients whose blood samples were collected for phenotypic and molecular studies along with 12-week iguratimod monotherapy.

Results

Iguratimod inhibited human ASC generation without affecting B cell activation and proliferation. Iguratimod showed only weak COX-2 activity. Gene set enrichment analysis (GSEA) identified that protein kinase C (PKC) pathway was targeted by iguratimod which was confirmed by PKC activity detection. Furthermore, early growth response 1 (EGR1), a target of PKC and a non-redundant TF for ASC differentiation, was found to be the most downregulated gene in iguratimod-treated B cells. Lastly, iguratimod monotherapy decreased peripheral ASCs and was associated with improved disease activity. The expression of major ASC-related TFs, including EGR1, was similarly downregulated in patient blood samples.

Conclusions

Iguratimod inhibits ASC differentiation both in vitro and in RA patients. Our study suggests that PKC/EGR1 axis, rather than COX-2, is critically involved in the inhibitory effect by iguratimod on human ASC differentiation. Iguratimod could have a broader application to treat B cell-related autoimmune diseases in clinics.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1874-2) contains supplementary material, which is available to authorized users.

Suspected drug-induced liver injury associated with iguratimod: a case report and review of the literature

Background

Iguratimod is a novel anti-rheumatic drug with the capability of anti-cytokines as report goes. It has been reported that iguratimod is effective and safe for rheumatoid arthritis and other rheumatisms. As side effects, iguratimod can cause gastrointestinal reactions, dizziness, headache and itchy.

Case presentation

In this case report, a 60-year-old female patient was admitted with suspected drug-induced liver injury (DILI) caused by iguratimod. The causality assessment was done by the updated RUCAM, and the possibility of the case in our paper diagnosed as highly probable for the score was 9 points. Iguratimod was discontinued immediately, and methylprednisolone was used for acute liver injury and Sjogren’s syndrome. The data showed the patient has improved gradually, and she was discharged on day 27. The true incidence of iguratimod-related hepatotoxicity and its pathogenic mechanism are largely unknown. It is difficult to recognize and diagnose DILI, and there is no standard for diagnosis of DILI. At the same time, the DILI is still lack of specific treatment.

Conclusions

Based on this rare case of severe liver injury, we recommend careful monitoring of liver function throughout iguratimod treatment for diseases.

Safety and effectiveness of iguratimod in patients with rheumatoid arthritis: Final report of a 52-week, multicenter postmarketing surveillance study

OBJECTIVES

We evaluated the long-term (52 weeks) safety and effectiveness of iguratimod (IGU) in patients with rheumatoid arthritis (RA).

METHODS

This multicenter, prospective, observational study included all evaluable RA patients who received IGU since its market launch in 2012. We evaluated adverse events (AEs); adverse drug reactions (ADRs); ADRs of special interest, including liver and renal dysfunctions, interstitial lung disease, gastrointestinal and blood disorders, and infection; and change in Disease Activity Score 28-C-reactive protein (DAS28-CRP) at week 52.

RESULTS

Safety and effectiveness were analyzed in 2666 and 1614 patients, respectively. The incidences of AEs, serious AEs, ADRs, and serious ADRs were 46.92, 7.35, 38.26, and 4.58%, respectively. The incidence of ADRs peaked at approximately 4 weeks of treatment. Subsequently, the ADR incidence did not increase over time. Improvement of RA activity was shown up to week 52.

CONCLUSION

Long-term treatment with IGU in patients with RA resulted in a tolerable safety profile and an improvement in RA activity. IGU could be considered a useful treatment option for patients with RA.

Novel disease-modifying anti-rheumatic drug iguratimod suppresses chronic experimental autoimmune encephalomyelitis by down-regulating activation of macrophages/microglia through an NF-κB pathway

We aimed to elucidate the effects of iguratimod, a widely used anti-rheumatic drug with no severe side effects, on chronic experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Iguratimod was orally administered to mice immunised with myelin oligodendrocyte glycoprotein peptide 35–55. Preventive administration of iguratimod from the time of immunisation was found to markedly reduce the clinical severity of acute and chronic EAE. Pathologically, iguratimod treatment significantly reduced demyelination and infiltration of CD3⁺ T, F4/80⁺, and CD169⁺ cells into the spinal cord, and suppressed macrophage/microglia activation in the parenchyma at the acute and chronic stages compared with vehicle treatment. Therapeutic administration of iguratimod after the onset of clinical symptoms significantly ameliorated the clinical severity of chronic EAE and reduced demyelination, T helper (Th)1/Th17 cell infiltration, macrophage/microglia activation, and nuclear factor (NF)-κB p65 and cyclooxygenase-2 expression in the spinal cord. In vitro, iguratimod treatment inhibited nuclear translocation of NF-κB p65 and down-regulated pro-inflammatory responses in macrophages and microglia. Our results suggest that iguratimod ameliorates acute and chronic EAE by suppressing inflammatory cell infiltration and immune cell activation, partly through inhibition of NF-κB p65, supporting the therapeutic potential of this drug for not only acute, but also chronic MS.

Incidence and Risk Factors for Infections Requiring Hospitalization, Including Pneumocystis Pneumonia, in Japanese Patients with Rheumatoid Arthritis

Objective

Rheumatoid arthritis (RA) may be complicated by different infections, but risk factors for these are not fully elucidated. Here, we assessed the incidence of and risk factors for infections requiring hospitalization (IRH) including pneumocystis pneumonia (PCP) in patients with RA.

Methods

We retrospectively surveyed all RA patients treated at our hospital from 2009 to 2013, for whom data were available on demographic features, medications, comorbidities, and severity of RA. Multivariate logistic regression analysis was applied to calculate adjusted odds ratios (ORs) for factors associated with the occurrence of IRH.

Results

In a total of 9210 patient-years (2688 patients), there were 373 IRH (3.7/100 patient-years). Respiratory tract infections were most frequent (n = 154, and additionally 16 PCP), followed by urinary tract infections (n = 50). Significant factors for PCP included higher age (≥70 years; OR 3.5), male sex (6.6), underlying lung disease (3.0), use of corticosteroids (4.8), and use of biologics (5.4). Use of methotrexate (5.7) was positively associated with PCP but negatively with total infections (0.7). Additionally, functional disorders and higher RA disease activity were also related to total infections.

Conclusions

Risk factors for infection should be taken into account when deciding treatment for the individual RA patient.