Etanercept for Spondyloarthritis: Impact on Disease Progression

Treatment with etanercept in patients with nonradiographic axial spondyloarthritis (nr-axSpA) is associated with reductions in structural erosions in the sacroiliac joints and with increases in backfill, correlating with improvements in clinical outcomes as early as 12 weeks, according to the results of a recent randomized controlled trial published in Annals of the Rheumatic Diseases.

Patients were randomly assigned to double-blind treatment with etanercept 50 mg/wk or placebo for 12 weeks in the Effect of Etanercept on Symptoms and Objective Inflammation in nr-axSpA (EMBARK) trial (ClinicalTrials.gov identifier: NCT01258738). Structural lesions as assessed on T1-weighted magnetic resonance imaging (MRI) at 12 weeks were scored by 2 independent researchers using the Spondyloarthritis Research Consortium of Canada (SPARCC) sacroiliac joint structural score. All participants were evaluated for change in SPARCC sacroiliac joint structural score and the correlation with improvement in clinical outcomes.

The MRI scans of 185 patients (etanercept, n=88; placebo, n=97) were reviewed. No significant differences in mean SPARCC sacroiliac joint structural score between the etanercept and placebo groups were noted at baseline. From baseline to 12 weeks, however, change in mean SPARCC sacroiliac joint structural score was significantly greater with etanercept than with placebo for erosion (-0.57 vs -0.08, respectively; adjusted P =.017) and for backfill (0.36 vs 0.06, respectively; adjusted P =.022).

A treatment difference was also observed for the subgroup of patients with sacroiliac joint inflammation on MRI at baseline (defined as an SPARCC bone marrow edema score ≥2) for erosion (-0.81 vs -0.13 with etanercept vs placebo, respectively; P =.007) and backfill (0.48 vs 0.08, with etanercept vs placebo, respectively; P =.032).

The investigators concluded that additional research on the use of radiographic end points in long-term prospective studies will contribute to understanding the effect of etanercept therapy on new bone formation and maintenance of clinical response beyond 2 years in these patients with early disease.

Reference

Maksymowych WP, Wichuk S, Dougados M, et al. Modification of structural lesions on MRI of the sacroiliac joints by etanercept in the EMBARK trial: a 12-week randomised placebo-controlled trial in patients with non-radiographic axial spondyloarthritis [published online September 29, 2017]. Ann Rheum Dis. doi: 10.1136/annrheumdis-2017-211605