Long term data on efficacy and safety of anti-TNF treatment with infliximab in patients with ankylosing spondylitis (AS) beyond 5 years is lacking. These data are important because patients with AS usually are younger and withdrawal of anti-TNF therapy in these patients almost always leads to a disease relapse. Furthermore it is still unclear whether long term anti-TNF treatment in AS patients can inhibit radiographic progression. Patients who participated in the EASIC and the DIKAS trial respectively who were treated with infliximab within these studies for 7 and 10 years respectively are followed up by using clinical outcome parameters every 6 months assessing efficacy and safety of long term treatment. Furthermore radiographs of the spine, if done for clinical indication, are analyzed. It is hypothesized that anti-TNF treatment with infliximab is effective and safe over a time period of 9 and 12 years respectively and that long term anti-TNF therapy may inhibit radiographic progression of the spine.

Ankylosing spondylitis (AS) is the most frequent subtype of spondyloarthritides (SpA)(Braun et al.Lancet 2007, 369:1379-90). Treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) is the cornerstone of the treatment of the disease and is widely used to suppress inflammation and ameliorate spinal pain (Zochling et al.:Ann Rheum Dis 2006, 65:442-52). There is evidence that antitumour necrosis factor (TNF) therapy is highly effective in SpA, especially in AS and psoriatic arthritis. Thus, TNF blockers may even be considered as first line treatment in a patient with active AS whose condition is not sufficiently controlled with NSAIDs in the case of axial disease, and sulfasalazine or methotrexate in the case of peripheral arthritis (Zochling et al.:Ann Rheum Dis 2006, 65:442-52). Long-term data on anti-TNF therapy in patients with AS are rather limited. Infliximab in a dosage of 5mg/kg was shown to be efficacious over 5 years, including a short period of withdrawal and readministration (Baraliakos et al.:Arthritis Res Ther 2005, 7: R439-44; Baraliakos et al.:J Rheumatol 2007, 34: 510-5; Braun J et al: Ann Rheum Dis 2008, 67: 340-5). In our EASIC study the investigators have also shown the efficacy and safety of infliximab treatment in patients with AS over 5 years. Long term data for the treatment of AS with etanercept has proven the efficacy as well (Dijkmans B et al.:J Rheumatol 2009, 36: 1256-64). But long term data for efficacy and safety of treatment with anti-TNF therapy beyond a time period of 5 years is lacking. These data on long term treatment are essential for several reasons. At first patients with AS are predominantly of younger age. When taking into account that withdrawal of anti-TNF therapy leads to disease relapse in a very high proportion of patients , anti-TNF therapy in AS patients is most often designed as a continuous therapy on a long term basis. The second reason for the need of long term data beyond 5 years is the ongoing debate whether anti-TNF agents have the potential to inhibit radiographic progression (Baraliakos X et al.:Ann Rheum Dis 2005, 64:1462-6; van der heijde D et al:Arthritis Rheum 2008, 58: 3063-70). Radiographic data on a larger cohort of patients treated with infliximab or other anti-TNF blockers for a long time period could contribute to answer this important question.

Inclusion Criteria:

• Established diagnosis of ankylosing spondylitis according to the modified New York criteria
• Participation in the EASIC trial or participation in the DIKAS/TNF bei AS-trial
• Completion of the EASIC extension or the DIKAS trial
• Presence of written informed consent from the patient

Exclusion Criteria:

• None

Patients with ankylosing spondylitis who have completed:

1. the trials ASSERT, EASIC and EASIC extension (overall 7 years)
2. the trial DIKAS (overall 10 years)

and who are still on infliximab or another anti-TNF agent wor who have terminated anti-TNF treatment