Low-dose infliximab (3 mg/kg) significantly reduces spinal inflammation on magnetic resonance imaging in patients with ankylosing spondylitis: a randomized placebo-controlled study.
OBJECTIVE
To evaluate the influence of low-dose infliximab (IFX) on spinal inflammation scored by magnetic resonance imaging (MRI). The dose recommended for rheumatoid arthritis (3 mg/kg) is also clinically effective for ankylosing spondylitis (AS), although effects on spinal inflammation as defined by MRI have yet to be described in a placebo-controlled trial.


METHODS
In a 12-week double-blind period, patients were randomized 1:1 to receive either IFX 3 mg/kg at 0, 2, and 6 weeks, or placebo. Spinal inflammation in discovertebral units (DVU) was measured by the Spondyloarthritis Research Consortium of Canada (SPARCC) MRI Index at baseline and 12 weeks by 3 readers blinded to timepoint and treatment allocation. We also compared reliability and discrimination of the SPARCC MRI index based on evaluation of the entire spine (23 DVU score) compared to assessment of only the 6 most severely affected DVU (6 DVU score).


RESULTS
At Week 12, patients treated with IFX experienced mean reductions of 55.1% and 57.2% in the 6 DVU and 23 DVU SPARCC scores, respectively, compared with a mean increase of 5.8% and decrease of 3.4% in 6 DVU and 23 DVU scores, respectively, for patients taking placebo (p < 0.001). A large treatment effect (Guyatt's effect size >or= 1.7) and high reliability was evident and comparable between 6 DVU and 23 DVU scoring methods.


CONCLUSIONS
Treatment with low-dose IFX leads to a large treatment effect on spinal inflammation as measured by MRI. Scoring for inflammation of only the most severely affected regions of the spine by MRI is comparable to assessment of the entire spine.
Maksymowych
Walter P
WP
Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. walter.maksymowych@ualberta.ca
Salonen
David
D
Inman
Robert D
RD
Rahman
Proton
P
Lambert
Robert G W
RG
D000328:Adult; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001855:Bone Marrow Diseases / Q000473:pathology; D002986:Clinical Trials as Topic; D004185:Disability Evaluation; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D004487:Edema / Q000473:pathology; D005260:Female; D006304:Health Status; D006801:Humans; D007249:Inflammation / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D000069285:Infliximab; D007403:Intervertebral Disc / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D020127:Recovery of Function; D012720:Severity of Illness Index; D013131:Spine / Q000473:pathology*; D013167:Spondylitis, Ankylosing / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D018501:Antirheumatic Agents; D000069285:Infliximab