Safety and efficacy of combination therapy of iguratimod with methotrexate for patients with active rheumatoid arthritis with an inadequate response to methotrexate: An open-label extension of a randomized, double-blind, placebo-controlled trial

Objective. To obtain safety and efficacy data on combination treatment with iguratimod and methotrexate (MTX) in an open-label extension study in patients with active rheumatoid arthritis (RA). Methods. Following a 28-week, randomized, double-blind trial of adding iguratimod or placebo to stable MTX therapy, patients entered a 24-week extension. Patients randomized to the iguratimod + MTX group continued treatment. Patients treated with placebo + MTX switched to iguratimod + MTX [the (placebo/iguratimod) + MTX group]. Results. In the iguratimod + MTX group, the rate of 20% improvement in American College of Rheumatology criteria (ACR20) at week 52 (71.3%) was similar to that at week 24 (69.5%). ACR50, ACR70 and Health Assessment Questionnaire Disability Index at week 52 significantly improved compared with the values at week 24. In the (placebo/iguratimod + MTX) group, the switch to iguratimod treatment significantly improved ACR20 from 30.7% at week 24 to 72.1% at week 52. Frequent adverse events for 52 weeks in the iguratimod + MTX group were nasopharyngitis, upper respiratory tract inflammation, stomatitis, lymphocyte decrease, AST increase, ALT increase and blood iron decrease. These adverse events were predominantly mild or moderate in severity. No deaths occurred. Conclusion. Efficacy and tolerance of iguratimod + MTX therapy was maintained to 52 weeks in patients with active RA with inadequate response to MTX.