Major reduction in spinal inflammation in patients with ankylosing spondylitis after treatment with infliximab: results of a multicenter, randomized, double-blind, placebo-controlled magnetic resonance imaging study

OBJECTIVE: To determine whether the effects of anti-tumor necrosis factor alpha (TNFalpha) in reducing the signs and symptoms of ankylosing spondylitis (AS) coincide with a reduction in spinal inflammation as detected by magnetic resonance imaging (MRI). METHODS: Pre- and postgadolinium T1 and STIR MR images of the spine were acquired at baseline and at week 24 in patients with AS who participated in a multicenter, randomized, double-blind, placebo-controlled study. Patients were randomly assigned at an 8:3 ratio to receive infusions of infliximab (5 mg/kg) or placebo at weeks 0, 2, and 6 and then every 6 weeks thereafter. MR images were obtained and evaluated independently by 2 readers who were blinded to the treatment allocation and time sequence of the images. RESULTS: A total of 194 patients in the infliximab group and 72 patients in the placebo group had evaluable images at baseline and week 24. About 80% of the patients had at least 1 active spinal lesion at baseline, as assessed by MRI. The improvement in the MRI Activity Score after 6 months was significantly greater in the patients who received infliximab (mean 5.02, median 2.72) than in those who received placebo (mean 0.60, median 0.0) (P < 0.001). Almost complete resolution of spinal inflammation was seen in most patients who received infliximab, irrespective of baseline activity. CONCLUSION: Patients with AS who received infliximab therapy showed a decrease in spinal inflammation as detected by MRI, whereas those who received placebo showed persistent inflammatory spondylitis.