Inefficacy of infliximab in ankylosing spondylitis is correlated with antibody formation

Table 1 Clinical reponse to infliximab in patients with ankylosing spondylitis in relation to infliximab levels and antibodies to infliximab after 24 weeks Patient BASDAI week 0 Mean: 5.5 Median: 5.2 BASDAI week 24 Mean: 1.9 Median: 1.8 ESR week 0 Mean: 43 Median: 26.5 ESR week 24 Mean: 11 Median: 8.5 CRP week 0 Mean: 52 Median: 25 CRP week 24 Mean: 8 Median: 5 ASAS 20% Infliximab level (ng/ml) ATI (ng/ml) 1 6.4 1.2 88 4 115 4 + 17 800 0 2 4.5 0.7 90 8 120 6 + 10 100 0 3* [dagger] [dagger] 22 26 14 21 [dagger] 0 7200 4 7.2 0.0 72 18 104 6 + 20 600 0 5* 4.7 3.1 12 18 7 20 + 0 15 600 6 4.5 1.8 23 9 11