TNF inhibitors in rheumatoid arthritis and spondyloarthritis : are they the same?

The advent of anti-tumour necrosis factor (TNF) drugs for rheumatoid arthritis (RA) or spondyloarthritis (SpA) has revolutionised the approach to patients with active disease who do not respond to conventional therapy. Although there are differences in their structure, morphology, pharmacokinetic properties and activity, all anti-TNF drugs ultimately neutralise the TNFα pathway of inflammation. However, despite their similar clinical efficacy, there are disagreements concerning drug survival and safety, with systematic reviews and meta-analyses confirming one result or the other. The fact that 20–30% of patients fail to respond to TNFα inhibitors indicates the possibility of primary resistance or the development of an immune response to the drugs themselves, which may act as antigens. The overall benefit of switching to another anti-TNF drug or a biological agent with a different mechanism of action, may be a valuable option in individual patients. There are few data concerning the use of anti-TNF drugs in patients with SpA but it seems that there are fewer adverse advents and higher drug survival in comparison with patients with RA.