Background Iguratimod (IGU) is csDMARDs developed in Japan and used in Japanese daily practice since 2012. Although IGU was developed as an anti-inflammatory drug at first, anti-rheumatic effect was found in experiments using type II collagen-induced arthritis model mice1). Main mode of action of IGU was thought to be inhibition of NF-kB resulted in decreased production of IL-6, IL-8 and TNF-alpha2). Clinical trials performed in Japan showed that efficacy of IGU was equal to sulfasalazine when used as monotherapy in patients with rheumatoid arthritis (RA)3). Additive efficacy to MTX was also shown in double-blind randomised trial in RA patients 4). Although several short-term results were published5), long-term results in daily clinical setting is lacking.
Objectives To investigate long-term outcome of IGU in patients with RA.
Methods 120 RA patients treated with IGU in our institute from April 2013 to June 2016 were included. Patients' characteristics, factors influencing to prescribing of IGU (why was IGU chosen as treating csDMARDs?), drug continuation rates (Kaplan-Meier) were investigated. Time course of disease activity (DAS28-CRP & SDAI) was also investigated using 65 cases who passed 2 years after starting of IGU.
Results Baseline characteristics was as below. Mean age was 64.9 years old, %female was 74.2%, mean RA duration was 10.0 years and MTX was concomitant in 50.0% of cases. 82% of patients had factors influencing to prescribing IGU and intolerance of dose escalation of MTX was 1st reason (23.3%), old age over 80 years old was 2nd reason (16.7%) and economical reason was 3rd (14.2%) (Table1). Drug continuation rates were 71.1% at 1 year, 48.9% at 2 years and 43.1% at 3 years (Fig1). Time course of disease activity (baseline-6 months-1 year-2 year) was 3.6–3.0–3.0–3.0 in DAS28-CRP. In 15 cases in remission of DAS28-CRP at 2 years, 2 were classified with high disease activity and 9 were moderate disease activity at baseline (Fig2).
Conclusions Efficacy of IGU in RA patients who had intolerance of MTX dose escalation or usage of biologics was observed. Although biological DMARDs is effective in RA patients, the cost is very expensive. IGU is comparative cheap (¥9,200/month) and suitable for RA patients with economical difficulties. As IGU decreased TNF-alpha production via inhibition of NF-kB, MTX+IGU may have similar mode of action with MTX+TNF inhibitor. Drug continuation rates were decreased over time and escape of efficacy may occur in some patients. Otherwise, IGU was very effective in some cases. Some of RA patients with high disease activity decreased disease activity greatly to remission state at 2 years after initiation of IGU.
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Disclosure of Interest None declared