Adalimumab Reduces Whole-Body MRI Indices of Inflammation in axSpA

Adalimumab (ADA) outperformed placebo in terms of reduction of axial, peripheral, entheseal, and whole-body inflammation assessed by magnetic resonance imaging (MRI) indices in patients with axial spondyloarthritis (axSpA), according to a report published in the Journal of Rheumatology.

The study investigators were interested in determining whether whole-body MRI (WBMRI) could be used to reliably indicate outcome measures in patients with axSpA taking ADA. WBMRI indices had never been used for this purpose before.

The ABILITY-1 trial (Clinicaltrials.gov identifier: NCT01029847) was a randomized, double-blind, placebo-controlled 48-week study that recruited 49 patients with axSpA (51% male) in Denmark between February 2010 and March 2014. Participants were divided to receive ADA 40 mg or placebo, subcutaneously, every other week for 6 weeks. Thereafter, all remaining individuals received ADA.

Standard MRI and WBMRI were performed at baseline and at weeks 6, 24, and 48. The primary outcome on WBMRI was the percentage of patients at week 6 demonstrating improvement in the total inflammation index beyond the smallest detectable change (>2.3).

At week 6, 11 (44%) ADA and 3 (13%) placebo patients met the WBMRI endpoint, with a risk difference of 32% (95% CI, 4%-59%; P =.025). In addition, at 6 weeks, 9 (36%) ADA and 4 (17%) placebo participants achieved the conventional MRI endpoint of minimally important change in the Spondyloarthritis Research Consortium of Canada (SPARCC) Spine MRI Inflammation Index, with a risk difference of 19%, but this was not statistically significant (95% CI, −9% to 47%; P =.20).

Also at week 6, 13 (52%) patients receiving ADA and 3 (13%) patients receiving placebo had reached the primary clinical outcome of >50% reduction (or a score of 2.0) on the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), demonstrating statistical significance (P =.005).

After adjustment for baseline measures of inflammation, at week 6, both the WBMRI and SPARCC indices revealed a significant difference in improvement when comparing ADA with placebo (P =.011 and P =.013, respectively).

Those patients with axSpA taking ADA vs placebo saw a marked reduction in total body inflammation, as well as reduced inflammatory activity in the spine and sacroiliac joints, peripheral joints, and entheses. Further investigation is warranted in future studies, using independent cohorts, to examine the utility of WBMRI as an objective measure to assess inflammatory activity in axSpA and related disorders, as well as to evaluate response to therapies for these conditions.

Disclosures

The work was supported by AbbVie, the manufacturer of adalimumab.

Reference

Krabbe S, Østergaard M, Eshed I, et al. Whole-body magnetic resonance imaging in axial spondyloarthritis: reduction of sacroiliac, spinal, and entheseal inflammation in a placebo-controlled trial of adalimumab [published online February 15, 2018]. J Rheumatol. doi: 10.3899/jrheum.170408