Figure 1 Median serum trough adalimumab concentrations (mg/l) over time in patients with anti‐adalimumab antibody concentrations of 12–100 AU/ml and >100 AU/ml compared with patients without anti‐adalimumab antibodies. Adalimumab concentrations were significantly lower in patients with high anti‐adalimumab antibody concentrations than in those with low (*p<0.001) or absent (**p<0.001) antibodies at week 16. The difference in adalimumab concentrations between patients with low antibody concentrations and no antibodies was also significant (p = 0.001). At week 28, differences between all groups were highly significant (p<0.001).