Recombinant Human Tumor Necrosis Factor Receptor (Etanercept) for Treating Ankylosing Spondylitis: A Randomized, Controlled Trial

Objective. To determine the safety and efficacy of etanercept in a multicenter, randomized, placebo-controlled, double-blind trial of adults with moderate to severe active ankylosing spondylitis (AS). Methods. Patients (n = 277) were treated with either etanercept 25 mg (n = 138) or placebo (n = 139) subcutaneously twice weekly for 24 weeks. The primary outcome measures were the percentages of patients achieving the Assessments in Ankylosing Spondylitis 20% response (ASAS20) at weeks 12 and 24. Other outcome measures included the percentage of patients achieving higher ASAS responses, and the safety of etanercept in patients with AS. All outcome measures were assessed at 2, 4, 8, 12, and 24 weeks. Results. Treatment with etanercept resulted in dramatic improvement. The ASAS20 was achieved by 59% of patients in the etanercept group and by 28% of patients in the placebo group (P < 0.0001) at week 12, and by 57% and 22% of patients, respectively, at week 24 (P < 0.0001). All individual ASAS components, acute-phase reactant levels, and spinal mobility measures were also significantly improved. The safety profile of etanercept was similar to that reported in studies of patients with rheumatoid arthritis or psoriatic arthritis. The only adverse events that occurred significantly more often in the etanercept group were injection-site reactions, accidental injuries, and upper respiratory tract infections. Conclusion. Etanercept is a highly effective and well tolerated treatment in patients with active AS.