The efficacy and safety of iguratimod treatment in stable systemic lupus erythematosus: a preliminary prospective cohort study.

Objectives: To evaluate the efficacy and safety of iguratimod as maintenance therapy in patients with stable systemic lupus erythematosus (SLE). Methods: Eligible participants were adults with stable SLE (SLEDAI-2K ≤4 for ≥12 weeks) and on stable standard-of-care medication. Patients treated with iguratimod (iguratimod group) were matched to those not receiving iguratimod (control group) using prospectively frequency matching at a 1:2 ratio. The coprimary end points were the flare rate at week 52 and the time to first flare. Results: This prospective cohort study consecutively screened 220 patients, of whom 52 meeting the inclusion criteria were enrolled. The final analysis included 16 patients in the iguratimod group and 31 in the control group. In the coprimary analysis, The flare rates at week 52 were 37.5% in the iguratimod group and 29% in the control group. Iguratimod was associated with a non-significant, numerically higher relapse risk versus control (HR = 1.45, 95% CI 0.57 to 3.74), with sensitivity analyses confirming the direction of this trend. No significant between-group differences were observed in the changes of secondary endpoints. Regarding safety, iguratimod was well-tolerated, and no serious adverse events were reported. Conclusion: This cohort study of 52 stable SLE patients found that the 52-week flare risk did not differ significantly between those exposed to iguratimod and those who were not. However, these null findings should be interpreted with caution and are not evidence of equivalence.