Persistent reduction of spinal inflammation as assessed by magnetic resonance imaging in patients with ankylosing spondylitis after 2 yrs of treatment with the anti-tumour necrosis factor agent infliximab

Abstract

Objectives: Patients with ankylosing spondylitis (AS) benefit from anti-TNF therapy both on a clinical basis and as depicted by magnetic resonance imaging (MRI). It is not known whether spinal inflammation remains suppressed over time. Our objective was to assess spinal inflammation by MRI in AS patients after 2 yr of continuous infliximab treatment.

Methods: Twenty patients with active AS were examined by MRI at baseline, after 3 months (end of placebo-controlled-phase) and after 2 yr of continuous infliximab therapy (5 mg/kg/6 weeks). T1 pre- and post-gadolinium (T1/gadolinium-diethylenetriamine-pentaacetic acid) and short tau inversion recovery (STIR) MRI sequences were performed and read by one blinded reader using the ASspiMRI score.

Results: Spinal inflammation, detected by MRI in all patients at baseline, decreased after 3 months only in the infliximab group in both MRI sequences. Persistent improvement of spinal inflammation was seen after 2 yr by scoring STIR sequences, with a mean score of 4.6 +/- 5.9 vs 15.2 +/- 13.2 at baseline (P = 0.01). On an individual level, inflammatory spinal lesions decreased from 6.7 +/- 5.0 per patient at baseline to 2.2 +/- 1.8 after 2 yr (P = 0.003). Improvement in spinal inflammation was found in all patients by both MRI sequences. Only a minor degree but some spinal inflammation was still present after 2 yrs.

Conclusion: Spinal inflammation in MRI was persistently reduced in all patients constantly treated with infliximab, but it was not completely eradicated. Disease activity parameters did not directly correlate with MRI, but both pointed in the same direction. Both types of information may be useful for the definition of response to anti-TNF therapy.