Switching anti-TNF therapy in ankylosing spondylitis

Sir, The introduction of anti-TNF drugs has revolutionized the management of ankylosing spondylitis (AS) [1] and the efficacy of these drugs has been confirmed in clinical trials [2–4]. However, a significant proportion of patients withdraw from treatment because of inadequate efficacy (IE) or adverse effects (AEs). Because there are significant differences between chemical structure of anti-TNF drugs and mechanism of action there is a rationale for switching in these circumstances. Data from patients with RA suggest that switching from one anti-TNF drug to another is effective [5] and now it has become common practice to switch in RA.Very few data however are available regarding the potential benefits of switching in AS. Coates et al. [6] report a favourable clinical outcome from their cohort of whom 15 patients were switched to a second drug; 14 showed a significant and sustained response. To our knowledge, this is the first study addressing anti-TNF drugs and switching in patients with established AS.