Early etanercept treatment of no benefit in suspected nonradiographic axial SpA

Initiating patients with suspected nonradiographic axial spondyloarthritis (SpA) with high disease activity on etanercept without first getting a positive finding on sacroiliac (SI) joint magnetic resonance imaging (MRI) and/or confirming an elevation in C‐reactive protein (CRP) level may be a futile effort, according to a study.

A total of 80 tumour necrosis factor inhibitor–naive patients with inflammatory back pain with at least two SpA features and high disease activity (Bath Ankylosing Spondylitis Disease Activity Index score ≥4) were randomized to receive etanercept (n=40) or placebo (n=40) for 16 weeks and subsequently followed for 8 additional weeks (to 24 weeks from baseline) without study medication. Treatment was given without the requirement of a positive finding on MRI of the SI joint and/or increased CRP level.

The mean age of the population was 34 years, and 64 percent were female. Baseline patient characteristics were similar in the treatment groups.  At week 16, as many patients on etanercept as on placebo achieved the primary endpoint of Assessment of SpondyloArthritis international Society 20 (ASAS20) response (16.7 percent vs 11.1 percent; relative risk, 0.7, 95 percent confidence interval, 0.2–2.2; p=0.5).

Among the disease parameters examined, only the erythrocyte sedimentation rate (ESR) showed greater improvement in the active treatment group at week 16 (–2.2 vs –1.4 mm/hour), although the difference did not reach statistical significance.

Between 16 and 24 weeks, the Bath Ankylosing Spondylitis Metrology Index (BASMI), CRP level, and ESR worsened to a larger extent in the etanercept group than in the placebo group, with the difference being significant for the CRP level.

The findings indicate that early treatment with etanercept is not beneficial to patients with suspected nonradiographic axial SpA without the requirement of a positive MRI result or increased CRP level.