Based on increasing evidence that tumor necrosis factor-a (TNF-a) is centrally involved in the development of ankylosing spondylitis (AS) and other spondyloarthropathies, researchers investigated the effectiveness of the TNF-a medication etanercept (Enbrel) in active AS. Data from this six-month, randomized, placebo-controlled trial shows that Etanercept is "clearly efficacious" for patients with active AS. Wyeth Pharmaceuticals, Enbrel's manufacturer, supported this study and provided the study drug.

Etanercept is not yet approved for use in AS by the Food and Drug Administration (FDA), but some rheumatologists prescribe it to their AS patients.

"The findings of this trial not only confirm the clear-cut efficacy of etanercept in the treatment of patients with active AS who are receiving conventional nonsteroidal anti-inflammatory drug (NSAID) therapy, but also show that no additional therapy with disease-modifying anti-rheumatic drugs (DMARDs) and steroids is needed to obtain these results," states study lead author J. Brandt, MD, from Free University in Berlin Germany.

The study enrolled 30 men in their thirties with active AS. They could continue treatment with NSAIDs before and during the study, but DMARDs and steroids medications had to be withdrawn prior to the study. During the first phase, 14 men received etanercept, 25 mg twice weekly, and 16 received placebo for six weeks. For the following six weeks, all 30 received etanercept. All participants were followed up for at least 24 weeks.

Results

• Treatment with etanercept resulted in at least a 50% regression of disease activity in 57% of these patients at week 6 versus 6% of the placebo-treated patients.
  
• After the placebo-treated patients switched to etanercept, 56% improved.
  
• Pain, function, mobility, and quality of life improved with etanercept but not with placebo at week 6.
  
• Average C-reative protein (CRP) levels decreased significantly with etanercept but not with placebo.
  
• Improvements continued throughout etanercept treatment, but relapses occurred in most patients (on average about six weeks after stopping treatment).
  
• No severe adverse events, including major infections, were observed during the trial.

The researchers suggest that on a short-term basis (three months), treatment with etanercept is effective in patients with active AS who are receiving NSAID therapy but not DMARDs or steroids. Since almost all patients experienced disease relapse within a few weeks of stopping etanercept, the study's authors suggests that etanercept must be administered continuously in most AS patients to achieve "permanent inhibition of the inflammatory process."

The article is published in a recent issue of the American College of Rheumatology's Arthritis & Rheumatism.