Title: SAT0022 Successful treatment of patients with severe undifferentiated spondyloarthropathy with the anti-tnfa antibody infliximab
Abstract: <h3>Background</h3> Anti-TNFa therapy has been successfully used in patients with active ankylosing spondylitis (AS;A&R June 2000). Whether this treatment is also efficacious in patients with undifferentiated spondyloarthropathies (uSpA), the second most frequent SpA subset, has not been assessed to date. <h3>Objectives</h3> To test the efficacy of the monoclonal anti-TNFa antibody infliximab in patients with severe uSpA. <h3>Methods</h3> Six uSpA patients (4 male, 2 female) with a median age of 36 years (range 19–49) were diagnosed according to the 1991 ESSG criteria. The median disease duration was 6.2 years (1.2–35 years). They had been refractory to other therapies including NSAIDs, steroids and sulfasalazine and were treated with infliximab in an open observational way at week 0, 2 and 6 and followed up for 12 weeks. Three patients received infliximab in a dosage of 3 mg/kg and the other three received 5 mg/kg. The leading clinical symptoms were peripheral arthritis (n = 6), inflammatory back pain (n = 6) and enthesitis of the heels (n = 4). HLA B27 was positive in 5/6 patients. No patient had sacroiliitis > grade II unilateral. The Bath AS disease activity index (BASDAI), the functional index (BASFI), pain on a visual analogue scale (VAS), and the Bath AS Metrology Index (BASMI) were assessed before, during and after therapy. Quality of life was measured using the Short Form (SF) 36 instrument. <h3>Results</h3> All patients improved after 1–3 days. There was a more substantial response in the group treated with 5 mg/kg infliximab then in the 3 mg/kg group. The range of the BASDAI in the 5 mg/kg group was 7.0 -7.6 (3 mg/kg-group: 7.7–8.6) before and 6 weeks after the third infusion 0.7–2.7 (3 mg/kg-group: 1.7–7.8). The functional index also improved in all but one patient: the BASFI values had decreased from 7.0–7.6 in the 5 mg/kg group (3 mg/kg-group: 6.7–8.5) to 0.8–2.7 (3 mg/kg-group: 0.8–8.4). Pain on a VAS improved in the 5 mg/kg group from 7.1–7.7 (3 mg/kg-group: 5.1–9.0) to 0.8–2.6 (3 mg/kg-group: 1.2–8.1). Joints, entheses and spinal symptoms improved equally. CRP levels dropped from <6.0–120 mg/l before therapy to <6.0–15.6 mg/l at week 12. No side effects occurred. There was improvement in all 8 SF-36 concepts assessed at baseline and at week 12; the improvement was significant for the concepts bodily pain and vitality. <h3>Conclusion</h3> These data suggest that anti-TNFa therapy has significant short-term efficacy in severe uSpA. Infusions with 5 mg/kg infliximab might be more effective than 3 mg/kg in SpA patients. Since it is known that 30–50% of uSpA patients develop AS over time it seems worthwhile to study whether this can be prevented by anti-TNFa therapy.