Inhibitory effect of a new anti-rheumatic drug T-614 on costimulatory molecule expression, cytokine production, and antigen presentation by synovial cells

Add-on effectiveness of methotrexate or iguratimod in patients with rheumatoid arthritis exhibiting an inadequate response to Janus kinase inhibitors: The ANSWER cohort study

OBJECTIVES

This multicenter, retrospective study evaluated the effectiveness of add-on methotrexate (MTX) or iguratimod (IGU) in patients with rheumatoid arthritis exhibiting an inadequate response to Janus kinase inhibitors (JAKis).

METHODS

Forty-five patients were treated with new additional MTX (n = 22) or IGU (n = 23) and followed for 6 months. Patients' background is as follows: age, 59.2 years; disease activity score of 28 joints with C-reactive protein (DAS28-CRP), 3.4; clinical disease activity index, 15.7; biological disease-modifying antirheumatic drug (DMARD)-switched cases, 77.8%; first JAKi cases, 95.6%; and JAKi treatment: tofacitinib (n = 25), baricitinib (n = 17), upadacitinib (n = 2), and peficitinib (n = 1) for 9.6 months.

RESULTS

Thirty-five patients continued the combination therapy for 6 months without a significant change in concomitant glucocorticoid or other conventional synthetic DMARDs. DAS28-CRP (MTX, 3.6 to 2.6, p < 0.05; IGU, 3.3 to 2.1, p < 0.001) and clinical disease activity index (MTX, 16.7 to 8.8, p < 0.05; IGU, 14.6 to 6.5, p < 0.01) improved significantly from baseline. Using the 2019 European League Against Rheumatism criteria, 45.4% (MTX) and 39.1% (IGU) achieved moderate or good response and 40.9% (MTX) and 39.1% (IGU) achieved American College of Rheumatology 20% improvement criteria.

CONCLUSIONS

Adding MTX or IGU to inadequate responders of JAKi can be considered as a complementary treatment.

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

OBJECTIVES

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

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 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.

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.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Iguratimod as a New Drug for Rheumatoid Arthritis: Current Landscape

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

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.

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.

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.

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

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

The three-year efficacy of iguratimod in clinical daily practice in patients with rheumatoid arthritis

Objectives: To assess the middle-term outcome of iguratimod (IGU) in rheumatoid arthritis (RA) patients. Methods: Sixty-nine RA patients (14 males and 55 females, mean age of 64.0 years) receiving IGU-containing therapies were enrolled. We divided these patients into three groups based on the treatment at the baseline: an IGU group, a methotrexate (MTX) plus IGU group, and a biologics plus IGU group. The baseline characteristics and clinical course were evaluated over three years. Predictive factors associated with the achievement of low disease activity (LDA) were statistically analyzed. Results: The survival rate of IGU therapy at 3 years was 40.6%. The disease activity was significantly decreased in the IGU group and MTX plus IGU group compared with the baseline. Furthermore, 38 patients (55.1%) were in remission or had LDA at 3 years. The patient gender, use of prednisolone (PSL) and DAS28-CRP at baseline were the factors associated with the achievement of remission or LDA at three years. Conclusion: IGU was effective without MTX or bDMARDs as well as in combination with MTX. A female gender, no use of PSL and a low DAS28-CRP at the initiation of IGU were associated with clinical remission or LDA achievement at three years.

The add-on effectiveness and safety of iguratimod in patients with rheumatoid arthritis who showed an inadequate response to tocilizumab

Objectives: To evaluate the effectiveness of add-on iguratimod (IGU) in patients with rheumatoid arthritis (RA) who showed an inadequate response to tocilizumab (TCZ), especially patients who were intolerant of an effective dose of methotrexate (MTX). Methods: Thirty-one patients with RA (22 women, age 62.4 years, disease duration 13.8 years, prior TCZ duration 35.7 months, 25 intravenous [8 mg/kg/4 weeks] and 6 subcutaneous [162 mg/2 weeks] TCZ treatments, concomitant MTX 8.5 mg/week [35.5%], and prednisolone (PSL) 4.3 mg/day [25.8%]) who showed an inadequate response to TCZ (disease activity score assessing 28 joints with C-reactive protein [DAS28-CRP] 2.9, clinical disease activity index [CDAI] 15.0, 28 secondary inadequate responders) were treated with additional IGU (final dose 41.7 mg/day) and enrolled in this 24-week, multicenter, retrospective study. Results: Twenty-nine patients (93.5%) continued the treatment for 24 weeks (one dropped out for pneumonia and one for digestive symptoms). The TCZ and the concomitant dose and rate of conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) (MTX, salazosulfapyridine [SASP], and tacrolimus [TAC]) were not significantly changed during this period. Outcome measures improved significantly, as follows: DAS28-CRP from 2.9 to 1.7 (p < .001); CDAI from 15.0 to 6.0 (p < .001); modified Health Assessment Questionnaire (mHAQ) from 0.8 to 0.6 (p < .05); and rheumatoid factor (RF) from 382.1 to 240.3 IU/mL (p < .001). Using the EULAR criteria, 64.5% achieved a moderate response, and 51.6% achieved ACR 20 at 24 weeks. Conclusion: Adding IGU to inadequate responders to TCZ may be a promising and safe complementary treatment option.

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.

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.

Iguratimod prevents ovariectomy‑induced bone loss and suppresses osteoclastogenesis via inhibition of peroxisome proliferator‑activated receptor‑γ

Iguratimod is known for its anti-inflammatory activities and therapeutic effects in patients with rheumatoid arthritis. It has previously been demonstrated that iguratimod attenuates bone destruction and osteoclast formation in the Walker 256 rat mammary gland carcinoma cell-induced bone cancer pain model. Therefore, it was hypothesized that iguratimod may additionally exhibit therapeutic effects on benign osteoclast-associated diseases including postmenopausal osteoporosis. In the present study, ovariectomized mice were used to investigate the effects of iguratimod in vivo. Bone marrow mononuclear cells were cultured to detect the effects of iguratimod on receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis in vitro and the molecular mechanisms involved. It was demonstrated that iguratimod may prevent ovariectomy-induced bone loss by suppressing osteoclast activity in vivo. Consistently, iguratimod may inhibit RANKL-induced osteoclastogenesis and bone resorption in primary bone marrow mononuclear cells. At the molecular level, peroxisome proliferator-activated receptor-γ (PPAR-γ)/c-Fos pathway, which is essential in RANKL-induced osteoclast differentiation, was suppressed by iguratimod. Subsequently, iguratimod decreased the expression of nuclear factor of activated T cells c1 and downstream osteoclast marker genes. The results of the present study demonstrated that iguratimod may inhibit ovariectomy-induced bone loss and osteoclastogenesis by modulating RANKL signaling. Therefore, iguratimod may act as a novel therapeutic to prevent postmenopausal osteoporosis.

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

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

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

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

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.

Disease activity early in treatment as a predictor of future low disease activity in RA patients treated with iguratimod

OBJECTIVES

This retrospective observational study aimed to examine the efficacy of iguratimod with and without concomitant methotrexate (MTX) and to estimate the adequate observational period for predicting low disease activity (LDA) achievement at 24 weeks in patients with rheumatoid arthritis (RA).

METHODS

All patients treated with iguratimod were registered in a Japanese multicenter registry. Multivariate analyses were performed to identify predictive factors for LDA achievement at 24 weeks. Receiver operating characteristic (ROC) curve analyses were performed to estimate the association of 28-joint disease activity score based on erythrocyte sedimentation rate (DAS28-ESR) at each time point with achievement of LDA at 24 weeks and determine a cut-off for DAS28-ESR.

RESULTS

A total of 123 patients were treated with iguratimod with (n = 65) or without (n = 58) MTX. Iguratimod therapy resulted in significant clinical improvement in both groups. Multivariate analysis revealed that DAS28-ESR at each time point was an independent significant predictor of LDA achievement at 24 weeks. Cut-off values of DAS28-ESR at 12 weeks based on ROC curves were 3.2 and 3.6 in patients with and without MTX, respectively.

CONCLUSIONS

Iguratimod was effective in RA patients in clinical practice. Our results suggest that 12 weeks may be a sufficient period to judge the medium-term efficacy of iguratimod in patients treated with and without MTX.

Iguratimod for the treatment of rheumatoid arthritis in Japan

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

Efficacy of the clinical use of iguratimod therapy in patients with rheumatoid arthritis

OBJECTIVE

Iguratimod (IGU) is a new synthetic disease-modifying antirheumatic drug intended to treat patients with rheumatoid arthritis (RA). We conducted a 24-week study on the efficacy of IGU in RA patients with daily clinical use.

METHODS

Forty-one patients were enrolled in this study, and the improvement in RA was evaluated every 4 weeks during the 24 weeks.

RESULTS

The patient's global assessment of the disease activity with a scale (Pt VAS) was significantly decreased beginning at week 4. The disease activity score (DAS) 28-erythrocyte sedimentation rate, DAS28-C-reactive protein (CRP), simplified disease activity index and clinical disease activity index all significantly decreased at week 24. The matrix metalloproteinase-3 level was significantly decreased by the combination treatment with methotrexate at week 24. According to a logistic regression analysis, the factor which was most associated with the achievement of low disease activity (DAS28-CRP < 2.7) at week 24 was the DAS28-CRP at week 0.

CONCLUSIONS

IGU had significant clinical effects on the RA patients within 24 weeks. IGU might therefore represent a new practical choice to treat RA patients.

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

OBJECTIVES

To investigate the efficacy and safety of iguratimod (T-614) in Japanese patients with active rheumatoid arthritis who had inadequate response to stable background methotrexate (MTX) alone.

METHODS

In this multicenter, double-blind, controlled trial, a total of 253 patients were randomized at 2:1 ratio to either the iguratimod group or the placebo group. Iguratimod was orally administered at dosages of 25 mg/day for the first 4 weeks (25 mg once daily) and 50 mg/day for the subsequent 20 weeks (25 mg twice daily). MTX at dosage of 6 or 8 mg/week was administered to patients in both groups.

RESULTS

The rate of 20 % improvement in American College of Rheumatology criteria (ACR20) at week 24 was 69.5 % in the iguratimod group compared with 30.7 % in the placebo group (P < 0.001). Significant improvements in the ACR50, ACR70, Health Assessment Questionnaire Disability Index, Disease Activity Score 28 <3.2, and rheumatoid factor were also observed. The most commonly reported adverse events (AEs) were blood iron decrease, nasopharyngitis, and lymphocyte decrease. These AEs were mild or moderate in severity. No deaths occurred.

CONCLUSION

The study results suggest that iguratimod in combination with MTX was efficacious and had a manageable safety profile.

Efficacy and safety of iguratimod compared with placebo and salazosulfapyridine in active rheumatoid arthritis: a controlled, multicenter, double-blind, parallel-group study

We conducted a 28-week, randomized, double-blind, parallel-group study of iguratimod in 376 Japanese patients with active rheumatoid arthritis to compare the efficacy and safety of the drug with those of placebo and salazosulfapyridine. In the American College of Rheumatology (ACR) 20 response rate, iguratimod was superior to placebo (53.8% versus 17.2%; Fisher's exact test, P < 0.001) and was not inferior to salazosulfapyridine (63.1% versus 57.7%, 95% confidence interval for the rate difference, -7.9% to 18.7%). Iguratimod began exhibiting its therapeutic effect within 8 weeks after the initiation of treatment and was effective even in patients who had a poor response to previous treatment with disease-modifying antirheumatic drugs. No statistically significant difference was noted in the incidence of adverse reactions between iguratimod and salazosulfapyridine. The study results suggest that iguratimod could become a new option for the treatment of rheumatoid arthritis.

Significant inhibition of TRAIL-mediated fibroblast-like synovial cell apoptosis by IFN-gamma through JAK/STAT pathway by translational regulation

The pathway of interferon-gamma (IFN-gamma)-induced suppression in tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-mediated apoptosis of fibroblast-like synovial cells (FLS) was investigated. rTRAIL triggered FLS apoptosis in a type II cell death manner, whereas IFN-gamma pretreatment significantly inhibited TRAIL-mediated apoptosis. As disruption of mitochondrial transmembrane potential (DeltaPsim), Leu-Glu-His-Asp ase (IETD ase) activity, and the appearance of hypodiploid DNA + cells were markedly suppressed in IFN-gamma-treated FLS in response to TRAIL, IFN-gamma-induced suppression was supposed to achieve at upstream of caspase-8. IFN-gamma rapidly phosphorylated signal transducers and activators of transcription 1 (STAT1), STAT3, and STAT6 as well as ERK, whereas enhanced neither phosphorylation of Akt nor nuclear translocation of nuclear factor kappaB (NF-kappaB) p65. Janus kinase (JAK)-induced phosphorylation of STAT1/3/6, which acts at translational regulation, seemed to be crucial because chemical inhibition of JAK as well as cycloheximide (CHX) abolished both the phosphorylation of STAT1/3/6 and the IFN-gamma-induced inhibitory effect. Although ERK was phosphorylated through IFN-gamma, chemical inhibition of ERK by PD98059 did not abolish the IFN-gamma-induced inhibitory effect. The authors tried to determine the responsible molecules; however, expression of TRAIL receptors; pro-caspase-3/-8/-9; Fas-associated death domain protein (FADD); tumor necrosis factor receptor 1-associated death domain protein (TRADD); silencer of death domain (SODD); FLICE inhibitory protein (FLIP); and Bcl-2, Bcl-xL, and Bax in FLS was not modulated by IFN-gamma. Although the authors have not yet clarified the precise mechanism, these data suggest that IFN-gamma/JAK/STAT pathway, which is supposed to be activated in inflammatory rheumatoid arthritis (RA) synovial tissues, contributes to form apoptosis resistance phenotype of the cells in situ, leading to a marked increase in cellularity of synovial cells.

A novel anti-rheumatic drug, T-614, stimulates osteoblastic differentiation in vitro and bone morphogenetic protein-2-induced bone formation in vivo

T-614 (N-[3-(formylamino)-4-oxo-6-phenoxy-4H-chromen-7-yl]methanesulfonamide), a newly developed anti-rheumatic drug under clinical trial, is an anti-inflammatory agent which has been reported to show the inhibitory effect of bone destruction in vivo arthritis model. We found that T-614 stimulated osteoblastic differentiation of stromal cell line (ST2) and preosteoblastic cell line (MC3T3-E1) in the presence or absence of recombinant human bone morphogenetic protein-2 (rhBMP-2). Calcium content of mineralized nodules was 14-fold elevated by the addition of T-614 in the presence of rhBMP-2 in ST2 but not MC3T3-E1. Oral administration of T-614 to mice also promoted rhBMP-2 induced bone formation in vivo. Northern blot analysis showed that transcriptional level of osterix, an essential transcription factor for osteoblastic differentiation, was 3-fold increased by T-614 with rhBMP-2 in ST2. Taken together, these results suggested that T-614 possessed anabolic effects on bone metabolism, besides suppressor of bone resorption, by increased expression of osterix.