Joachim Sieper, MD, of the University of Berlin, Germany, reported at the 2004 annual meeting of the American College of Rheumatology (ACR). "Fifty percent of ankylosing spondylitis patients show at least a 50% improvement in disease activity upon treatment with TNF-blockers," Dr. Sieper said during an ACR symposium on October 20 th .
The anti-TNF-α agents infliximab and etanercept are both effective in reducing the symptoms of ankylosing spondylitis, according to Dr. Sieper, an investigator for 2 recent trials, each involving one of the agents. 1,2 "A similar result is achieved both with infliximab and etanercept," he said, adding that "adalimumab seems to have comparable efficacy based on preliminary results."
Once a patient is diagnosed with ankylosing spondylitis, clinicians should first try to see if he or she will respond to nonsteroidal anti-inflammatory drugs (NSAIDs), Dr. Sieper pointed out, adding that clinicians should attempt at least 2 different NSAIDs over a 3-month period before considering the biologic agents.
If there is an increased activity index ― a score of 4 or more on the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), plus affirming expert opinion based on positive laboratory and imaging studies, the anti-TNF-α agents should be initiated. Although the high cost of the biologic agents is a factor that may influence the decision to use them, Dr. Sieper noted that the drugs favorably impact quality of life, 3 and one study with infliximab indicates that sick leave decreases as patients with ankylosing spondylitis remain on treatment. 4
In a study of 26 individuals with the disease, the group averaged 16 days of sick leave in the previous year prior to treatment. After 1 year of infliximab treatment, the average duration of sick leave was 10 days; after 2 years of treatment, the average duration of sick leave was 4 days.
However, getting the proper diagnosis of ankylosing spondylitis is not simple, as explained during the symposium by Martin Rudwaleit, MD, a rheumatologist at Charité University Hospital in Berlin, Germany. Dr. Rudwaleit noted that the prevalence of ankylosing spondylitis is about 0.2% to 0.8% of the population. While the disease usually manifests itself in the third decade of life, "time from first symptoms to diagnosis of ankylosing spondylitis is 5 to 7 years," he added. This is probably due to a low awareness of the disease and other spondyloarthritis conditions, according to Dr. Rudwaleit, who pointed out that "the relatively late appearance of radiographic sacroiliitis, a definitive diagnostic criterion, also makes diagnosis difficult." 5
Dr. Rundwaleit proposed that a diagnosis could be made before radiographic evidence is seen if one considers that inflammatory back pain plus 2 or 3 other features ― a positive family history, heel pain, alternating buttock pain, psoriasis, and Crohn's disease ― give a relatively high degree of confidence that the condition is ankylosing spondylitis.
The moderator of the symposium, Muhammad Khan, MD, of Case Western Reserve University, Cleveland, Ohio, concurred with Dr. Rundwaleit that in ankylosing spondylitis, "the first 10 years of disease progression is critical, but the delay in diagnosis is 5 to 8 years." He also agreed that reliable diagnosis of the disease is possible without waiting until changes are seen on conventional x-rays.
In another talk during the symposium, Oliver Fitzgerald, MD, of St. Vincent's University Hospital, Dublin, Ireland, reviewed studies that indicated that psoriatic arthritis also appears to respond well to anti-TNF-α drugs. 6
"New targeted treatments offer promise for disease modification and prevention of joint damage and disability," Dr. Fitzgerald said. He noted that psoriatic arthritis is a chronic, progressive disease in the majority of patients, adding that anti-TNF-α drugs appear to work in both the skin and joints of these patients because T-cell activation and cytokine release are important in the pathogenesis of the disease as has been highlighted in studies. Dr. Fitzgerald said research shows that etanercept, infliximab, and adalimumab are effective against psoriatic arthritis.
References
1. Braun J, Brandt J, Listing J, et al. Two-year maintenance of efficacy and safety of infliximab in the treatment of ankylosing spondylitis. Ann Rheum Dis. 2004; Sept 23 [Epub ahead of print].
2. Calin A, Dijkmans BA, Emery P, et al. Outcomes of a multicentre randomised clinical trial of etanercept to treat ankylosing spondylitis. Ann Rheum Dis. 2004; Sep 2 [Epub ahead of print].
3. Braun J, Brandt J, Listing J, Zink A, Alten R, Golder W, et al. Treatment of active ankylosing spondylitis with infliximab: a randomised controlled multicentre trial. Lancet. 2002; 359:1187-1193.
4. Listing J, et al. Ann Rheum Dis. In press.
5. Rudwaleit M, Sieper J. Diagnosis and early diagnosis of ankylosing spondylitis. Z Rheumatol. 2004;63:193-202.
6. Kane D, FitzGerald O. Tumor necrosis factor-alpha in psoriasis and psoriatic arthritis: clinical, genetic, and histopathologic perspective. Curr Rheumatol Rep. 2004;6:292-298.