Effect of Etanercept on Structural Changes in the Sacroiliac Joint in Patients with Early Axial Spondyloarthritis

Study Objectives and Methodology

In patients with ankylosing spondylitis and non-radiographic axial spondyloarthritis, the efficacy of tumor necrosis factor inhibitors (TNFi) on clinical and radiographic signs of inflammation is well documented. However, the issue of early forms of the disease and its impact on structural lesions is less explored.

The primary objective of the presented study was to evaluate structural changes in the sacroiliac joint area determined by MRI. The secondary objective was to assess the relationship between structural changes and inactive disease (ASDAS < 1.3 for at least 2 consecutive controls within a 6-month timeframe).

Data from two clinical studies were used for the analysis, specifically EMBARK, which evaluated the efficacy of TNFi etanercept in patients with axial spondyloarthritis, and the observational study DESIR, from which data of patients who did not undergo targeted therapy in the first 2 years of follow-up were selected.

Results

Data from 163 patients in the EMBARK study and 76 in the DESIR study were evaluated in the analysis. As for baseline characteristics, patients in the EMBARK study had longer symptom duration, worse functional parameters, and higher disease activity.

A significantly higher proportion of patients with reduced erosive changes was observed in the etanercept group: 23.9% vs. 5.3% in the unadjusted analysis (p = 0.01) and 23.1% vs. 2.9% in the adjusted analysis (p = 0.01). In patients on etanercept with inactive disease determined by ASDAS score, a higher proportion of individuals with reduced erosive changes than with an increase was observed (32.7% vs. 4.8%; p < 0.001).

In the group with inactive disease determined by ASDAS score, a higher proportion of patients with reduced erosive changes and an increase in reparative tissue (so-called backfill) was observed compared to patients in other ASDAS categories. However, this trend was not significant across the categories, and reduction in erosive changes was observed even in patients who did not achieve a sustained response evaluated by ASDAS score.

Conclusion

The study results indicate that a higher proportion of patients on etanercept achieved a reduction in erosive changes compared to the control group without etanercept. However, no clear association between structural changes and inactive disease assessed by ASDAS score was found in the study.

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Source:

Maksymowych W. P., Claudepierre P., de Hooge M. et al. Structural changes in the sacroiliac joint on MRI and relationship to ASDAS inactive disease in axial spondyloarthritis: a 2-year study comparing treatment with etanercept in EMBARK to a contemporary control cohort in DESIR. Arthritis Res Ther 2021 Jan 29; 23 (1): 43, doi: 10.1186/s13075-021-02428-8.