Dose reduction of recombinant human tumor necrosis factor inhibitors (etanercept) can be effective in ankylosing spondylitis patients with synovitis of the hip in a Chinese population.

Ankylosing spondylitis (AS) is an immune-mediated inflammatory arthritis and enthesitis involving the spine and peripheral joints. In recent years, specific antagonist of tumor necrosis factor (anti-TNFα, etanercept) 50 mg weekly therapy has rapidly gained popularity for the treatment of AS. However, the dose of etanercept has not been determined in Asian, particularly Chinese populations. The purpose of the study was to evaluate the efficacy and safety of dose reduction of etanercept (50 mg/week in 4 weeks followed by 25 mg/week in 8 weeks) in the treatment of AS with synovitis of the hip, as against the conventional dose (50 mg/week in 12 weeks) in a Chinese population. Forty-three Chinese AS patients with synovitis of the hip were involved in this study. Seventeen of them were randomized to receive conventional dose of etanercept treatment and 26 were given a dose reduction regimen for 12 weeks. The primary efficacy endpoint was disease activity of response for AS at week 12, including Bath AS Disease Activity Index (BASDAI), the serum erythrocyte sediment rate (ESR), C-reactive protein (CRP), and assessment of synovitis of the hip by ultrasonography. At 12 weeks, all of the patients had responses to some extent and the efficacy variables improved significantly over time, but not between treatment groups. Nine patients experienced at least one adverse event (generally, infections and injection site reactions), most of them mild or moderate. In sum, the dose reduction of etanercept regimen in the 12-week AS treatment was confirmed as a safe and effective therapy as the conventional dose was given.