Radiographic progression in patients with ankylosing spondylitis after 4 yrs of treatment with the anti-TNF-α antibody infliximab

Objectives. Anti-tumour necrosis factor therapy with infliximab has been shown to improve signs and symptoms of patients with active ankylosing spondylitis (AS). The objective of this article was to study the effect of infliximab on structural changes in AS over 4yrs. Methods. Conventional radiographs of the cervical and the lumbar spine of 33 AS patients at baseline (BL), after 2 (FU1) and after 4yrs (FU2) of infliximab therapy were scored by the modified Stokes ankylosing spondylitis spinal score (mSASSS). Definite baseline damage was defined when at least one syndesmophyte (mSASSS >= 2) was seen. Definite radiographic progression was defined as a change from 0 or 1 to syndesmophytes or ankylosis (mSASSS >= 2). Results. The mean change over 4 yrs was 1.6 +/- 2.6 mSASSS units (P= 0.001), (0.9 +/- 2.3 for BL-FU1 vs 0.7 +/- 1.6 for FL11-F1.12). This is less radiographic progression in comparison with published data from the OASIS cohort (4.4 within 4yrs). Definite radiographic progression was found in 10/33 (30.3%) patients for BL-FU2. Patients with definite damage at BL developed more chronic changes at FU2 (2.3 +/- 3.1, P= 0.003) than those with no damage at BL (0.7 +/- 1.5, P= 0.08). Four out of seven patients with no damage at 13L showed radiographic deterioration after 4 yrs. The change of the mean mSASSS in comparison with 13L was significantly different after 2 (P= 0.007) but not after 4yrs of infliximab therapy. Conclusions. There is some radiographic progression after 2 and 4yrs of infliximab therapy in AS patients. A comparison with the historical OASIS cohort suggests that infliximab may decelerate progression of structural changes. Larger studies are needed to confirm this finding.