Matsubara T, Inoue H, Nakajima T, et al. Abatacept in combination with methotrexate in Japanese biologic-naive patients with active rheumatoid arthritis: a randomised placebo-controlled phase IV study. RMD Open 2018;4:e000813.

The article has been corrected since it was published online.

In the Results section of the abstract (page 1), sentence 4 should read “Radiographic non-progression rates (change in vdH-mTSS≤smallest detectable change (1.9)) were 88.1% and 75.4% in abatacept and placebo groups, respectively.”

In the “Radiographic assessment” paragraph of the Methods section (page 2), sentence three should read “The rate of radiographic non-progression at week 24, defined as the proportion of patients with a change from baseline vdH-mTSS ≤1.9 (smallest detectable change (SDC)),²⁰ was a secondary endpoint.”

In the “Radiographic assessment” section of the Results (page 7, paragraph 2), sentence two should read “The radiographic non-progressor rates in the abatacept plus MTX group and the placebo plus MTX group were evaluated by the proportion of patients with change from baseline in vdH-mTSS below SDC (1.9), 0.5 or 0 at week 24 and week 52 (see online supplementary table S1).”