Biological therapies in the spondyloarthritides--the current state

Abstract

Therapeutic options for patients suffering from the more severe spondyloarthritides (SpA) have been rather limited in the last decades. Evidence is now accumulating that anti-tumour necrosis factor (TNF) therapy is highly effective in SpA, especially in ankylosing spondylitis (AS) and psoriatic arthritis (PsA). Based on the data recently published concerning more than 1000 patients with AS and PsA, this treatment seems to be even more effective than in rheumatoid arthritis (RA). The anti-TNFalpha agents currently available, infliximab (Remicade), etanercept (Enbrel) and adalimumab (Humira), are approved for the treatment of RA in the USA and Europe. The situation for SpA is different from RA because there is an unmet medical need, especially in AS, since no therapies with disease-modifying anti-rheumatic drugs (DMARDs) are available for severely affected patients, especially those with spinal disease. Thus, TNF blockers may even be considered a first-line treatment in a patient with active AS and PsA whose condition is not sufficiently controlled with non-steroidal anti-inflammatory drugs (NSAIDs) in the case of axial disease, and sulphasalazine or methotrexate in the case of peripheral arthritis. For infliximab, a dose of 5 mg/kg is required, and intervals of between 6 and 12 weeks are necessary to constantly suppress disease activity-also a major aim for long-term treatment. The standard dosage of etanercept is 2 x 25 mg subcutaneously per week. There are almost no studies yet on adalimumab (standard dose in RA, 20-40 mg subcutaneously every 1-2 weeks) in SpA. Infliximab and etanercept are now both approved for AS in Europe. The efficacy of etanercept was first demonstrated in PsA, and it is now approved for this indication in the USA and Europe. There is preliminary evidence that both agents also work in other SpA, such as undifferentiated SpA (uSpA). Studies should be performed to document the long-term efficacy of this treatment. There is hope that ankylosis may be preventable, but it remains to be shown whether patients benefit from long-term anti-TNF therapy and whether radiological progression and ankylosis can be stopped. Severe adverse events have remained rare. Complicated infections including tuberculosis have been reported. These can largely be prevented by appropriate screening. As it stands now, the benefits of anti-TNF therapy in AS seem to outweigh these shortcomings.