Comparison of drug survival and clinical outcome in patients with ankylosing spondylitis treated with etanercept or adalimumab

J. Ruwaard, M. l’Ami, A. Marsman, E. Kneepkens, J. van Denderen, I. van der Horst-Bruinsma, M. Nurmohamed, G. Wolbink

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Objective: To compare rates of drug survival and clinical response during 2 years of follow-up in ankylosing spondylitis (AS) patients treated with etanercept or adalimumab in routine care. Method: Biological-naïve consecutive AS patients treated with etanercept (n = 163) or adalimumab (n = 82) were followed. Treatment discontinuation was due to inefficacy, adverse events, loss to follow-up, planning a pregnancy, or uveitis. Disease activity was assessed by the Ankylosing Spondylitis Disease Activity Score using C-reactive protein (ASDAS-CRP). Moderate disease activity was defined as an ASDAS-CRP < 2.1. Results: Twenty-seven patients (32.9%) treated with adalimumab and 30 (18.4%) with etanercept discontinued treatment. Cox regression analysis demonstrated a significant difference in survival rate between discontinuation of the drug in adalimumab patients compared with etanercept patients [hazard ratio (HR) 2.1, 95% confidence interval (CI) 1.3–4.5, p = 0.005; corrected for confounding factors: HR 2.5, 95% CI 1.3–4.5, p = 0.006]. There was no significant difference at 2 years of follow-up between the adalimumab- and the etanercept-treated patients in mean ± sd ASDAS-CRP (1.9 ± 1.1 and 2.0 ± 0.9, respectively, p = 0.624), and 23 out of 34 (67.6%) compared to 71 out of 117 (60.7%) reached ASDAS-CRP moderate disease activity (odds ratio 0.738, 95% CI 0.329–1.657, p = 0.530). Conclusion: No significant difference was found between AS patients treated with etanercept and those treated with adalimumab in mean ASDAS-CRP and reaching ASDAS-CRP minimal disease activity at 2 year follow-up. Drug survival rate was higher in etanercept- compared to adalimumab-treated patients. However, this should be interpreted cautiously as the risk of allocation bias cannot be excluded.

Original languageEnglish
Pages (from-to)122-126
Number of pages5
JournalScandinavian Journal of Rheumatology
Issue number2
Publication statusPublished - 4 Mar 2018

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