Objectives: To investigate the efficacy and safety of low-dose etanercept treatment after clinical remission of ankylosing spondylitis (AS) in the real world.
Methods: Data on 134 AS patients who were treated with etanercept for more than 12 months and achieved clinical remission (BASDAI<4 and CRP<0.5 mg/dL) were extracted from a large single centre registry. Drug survival and incidence of adverse events in 100 patients who reduced the dose during follow up (low-dose group) were compared with 34 patients who maintained the initial dose (standard-dose group). For minimisation of selection bias between the two groups, the same analyses were performed in a propensity score-matched population.
Results: Both groups showed similar BASDAI score and CRP levels during the follow-up. Drug survivals between the two groups were also comparable up to 4 years (vs. standard-dose group, adjusted HR=0.472, 95% CI 0.155-1.435). The same analysis performed after propensity score-matching showed concordant result. The incidence of injection site reactions in the low-dose group was significantly lower, and the incidence of other adverse events showed no differences between the two groups. In the low-dose group, dose reduction after more than 24 weeks of standard-dose treatment was associated with longer drug survival (adjusted HR=0.261, 95% CI 0.084-0.809).
Conclusions: Low-dose etanercept treatment after achieving clinical remission can be an alternative treatment option in terms of its comparable long-term efficacy and favourable safety in AS. More than 24 weeks of standard-dose treatment before dose reduction may be beneficial for longer drug survival in this strategy.