Long-term drug survival and clinical effectiveness of etanercept treatment in patients with ankylosing spondylitis in daily clinical practice.

Objectives: Randomised controlled trials and open-label extension studies have demonstrated the clinical efficacy and safety of tumour necrosis factor-alpha (TNF-α) blocking therapy in pre-selected study patients with ankylosing spondylitis (AS). Our aim was to investigate the 7-year drug survival and clinical effectiveness of etanercept treatment in AS patients in daily clinical practice.

Methods: Consecutive AS patients from the prospective observational GLAS cohort who started etanercept because of active disease were included and evaluated over 7 years according to a fixed protocol. Continuation of treatment was based on BASDAI improvement and/or expert opinion.

Results: Of the 89 included AS patients, 45 (51%) were still using etanercept at 7 years of follow-up. Reasons for treatment discontinuation were adverse events (n=22), inefficacy (n=13), or other reasons although good clinical response (n=9). Etanercept treatment resulted in a rapid (after 6 weeks) and sustained improvement in disease activity (BASDAI, ASDAS, CRP, physician GDA), spinal mobility, physical function (BASFI), quality of life (ASQoL), and extra-spinal manifestations (swollen joints, tender joints and tender entheses). Furthermore, concomitant NSAID or DMARD use decreased significantly during follow-up. At 7 years, low disease activity and remission were present in 67-73% and 29-30% of the 45 patients, respectively. Of the patients who discontinued etanercept, 18 switched successfully to a second or third TNF-α blocker during follow-up.

Conclusions: In a large cohort of AS patients treated with etanercept, approximately 50% continued this treatment for 7 years. Our broad evaluation of clinical endpoints proves the long-term effectiveness of etanercept treatment in daily clinical practice.