Therapy for ankylosing spondylitis: new treatment modalities

Abstract

The therapeutic options for patients suffering from the more severe forms of spondyloarthritis (SpA) have been rather limited in recent decades. There is now accumulating evidence that anti-tumour necrosis factor (anti-TNF) therapy is highly effective in SpA, especially in ankylosing spondylitis (AS) and psoriatic arthritis (PsA). Based on the data recently published on more than 200 AS patients, and more than 100 PsA patients, this treatment seems to be even more effective than it is in rheumatoid arthritis (RA). The two major anti-TNF-alpha agents currently available, infliximab (Remicade) and etanercept (Enbrel), are approved for the treatment of RA in Europe and in the USA. The situation in SpA is different from RA because there is an unmet medical need, especially in AS, because disease-modifying anti-rheumatic therapy is not available for severely affected patients. Thus, TNF blockers might even be considered first-line immunosuppressive treatment in patients with active AS who are not sufficiently treated with non-steroidal anti-inflammatory drugs (NSAIDs). For infliximab, a dose of 5mg/kg was required, and intervals between 6 and 12 weeks were necessary for constant suppression of disease activity - a major aim also for long-term treatment. However, it remains to be shown whether patients benefit from long-term therapy and whether radiological progression and ankylosis can be stopped. The optimal doses of infliximab might well be determined individually. Allergic reactions and increased susceptibility to tuberculosis are rare side-effects which need to be recognized early. As it stands now, the benefits of anti-TNF therapy in AS seem to outweigh these shortcomings. The efficacy of etanercept was first demonstrated in PsA. A double-blind study has now been performed in AS - with similar results. There is preliminary evidence that both agents also work in other SpA such as undifferentiated SpA. Hopefully, both agents will be approved soon for the short-term treatment of severe SpA. In parallel, studies should be performed to document the long-term efficacy and safety of this treatment.