In another study, Okamura et al. adopted a similar approach ina 52-week follow-up of 41 RA patients using iguratimod to evaluate its efficacy and safety.72 The disease activity score, CRP, disease activity indices, and matrix metalloproteinase-3 (MMP-3) were all significantly decreased, and only one case of Pneumocystis jiroveci pneumonia was recorded as an adverse effect. Here, MMP3 is linked to rheumatoid arthritis.