• ankylosing spondylitis
• tumour necrosis factor α
• infliximab

The spondyloarthropathies (SpA) comprise ankylosing spondylitis (AS), reactive arthritis, some forms of psoriatic arthritis/spondylitis, arthritis/spondylitis associated with inflammatory bowel disease, and undifferentiated SpA. AS is the most common subgroup with the most severe course of the disease. In two studies from Germany, one performed among blood donors and one in an outpatient clinic with special interest in SpA, AS was slightly more common than undifferentiated SpA.1 ,2 The prevalence for the whole group of SpA has been estimated in recent studies at between 0.6% and 1.9%.1 ,3 ,4 Thus it can be assumed that the SpA have a similar prevalence to rheumatoid arthritis (RA).

Only recently, researchers have started to investigate the burden of disease in patients with AS, both personally and economically. Although a direct comparison between RA and AS is difficult, because there are far more studies in RA and AS usually starts considerably earlier in life, some studies have now been performed. When age and sex matched patients with severe AS were compared with patients with severe RA the grade of disability was similar.5 Furthermore, work disability is clearly greater in patients with AS than in normal subjects.6 Thus SpA, in general, and AS, especially, is more prevalent than previously thought and active disease has a clear socioeconomic impact.

With this background it is rather surprising that there are no established disease modifying antirheumatic drugs (DMARDs) for AS. Although some of the treatments, such as sulfasalazine, seem to be effective for peripheral arthritis in patients with SpA, there is no such treatment for the axial manifestation. Not only is there no accepted DMARD treatment for this chronic rheumatic disease but also most of the few studies are—in comparison with RA treatment trials—of bad quality with small patient numbers and without …