Similar response rates in patients with ankylosing spondylitis and non-radiographic axial spondyloarthritis after 1 year of treatment with etanercept: results from the ESTHER trial

Objective We assessed whether there is a difference to etanercept (ETA) treatment in patients with ankylosing spondylitis (AS) compared with non-radiographic axial SpA (nr-axSpA) patients with a disease duration <5 years. Method AS (n=20) and nr-axSpA (n=20) patients who were treated with ETA for 1 year were compared for differences in baseline data and treatment effect. Clinical, laboratory and MRI of sacroiliac joints (SI-joints) and spine were analysed. Results At baseline, there were no significant differences between the 20 AS and the 20 nr-axSpA patients regarding age, disease duration, gender, HLA-B27 and clinical disease activity in terms of Bath AS Disease Activity Index (BASDAI), C-reactive protein and MRI SI-joint and spine scores in the AS compared with the nr-axSpA group. After 1 year of treatment with ETA the treatment effect was similarly good in AS and nr-axSpA (reduction of BASDAI by 3.3 (95% CI 2.2 to 3.8) vs 3.6 (95% CI 2.8 to 4.4) and reduction of AS Disease Activity Score by 1.8 (95% CI 1.5 to 2.2) vs 1.8 (95% CI 1.5 to 2.1), respectively. Conclusions The response rate to TNF-blockers does not differ between AS and nr-axSpA if the baseline data regarding symptom duration and disease activity are similar for the two groups.