Effectiveness of a modified dosing regimen with a lower maintenance dose of infliximab in the treatment of patients with ankylosing spondylitis and spondyloarthropathy

Abstract

AbstractObjective: Anti‐tumour necrosis factor therapy offers hope to patients with ankylosing spondylitis (AS) and spondyloarthropathy (SpA) refractory to conventional disease‐modifying antirheumatic drugs (DMARDs). However, it is expensive with the standard recommended dosing (5 mg/kg) every 6–8 weeks. We assess the effectiveness of treating AS and SpA with a modified lower maintenance dosing regimen of infliximab.Methods: An open‐labelled, prospective trial with subjects recruited from a local tertiary hospital. Patients either fulfilled the modified New York criteria for classification of ankylosing spondylitis (AS) or European Spondyloarthropathy Study Group (ESSG) classification criteria for SpA with active disease. After induction with infliximab at 5 mg/kg at week 0 and 2 (induction period), patients were given 3 mg/kg at week 6 and then 8‐weekly (maintenance period) to 22 weeks. The patients were assessed with a standard protocol to 30 weeks. Erythrocyte sedimentation rate, c‐reactive protein, Visual Analogue Scale (VAS) pain score, VAS global health score (GH), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Bath Ankylosing Spondylitis Functional Index (BASFI) were recorded. The Ankylosing Spondylitis Assessment (ASAS) 20, ASAS 40 and ASAS 5/6 were determined at the end of the study.Results: Eighteen Chinese patients were recruited (16 AS, 2 SpA; M : F 8 : 10), with the mean age of 38.2 years and mean disease duration of 8 years. Nine patients had extra‐articular manifestations (9 uveitis, 1 aortic valve insufficiency, 1 colitis). Thirteen of these were on concurrent DMARDs. When comparing baseline with 6, 14, 22 or 30 weeks, erythrocyte sedimentation rate, c‐reactive protein, VAS pain, VAS GH, BASDAI and BASFI all achieved a statistical significant reduction. Half of the patients (9/18) achieved ASAS20 and ASAS40, whereas 61.1% (11/18) achieved ASAS5/6 at the end of the study. Partial remission was achieved in 22.2% (4/18) of subjects studied. Improvement in VAS pain score, VAS GH and BASFI after the induction period was sustained during the maintenance period.Conclusion: The modified dosing regimen with a lower maintenance dosage of infliximab was feasible and effective in the treatment of spondyloarthropathy. This would allow more patients to access and afford the therapy. A larger cohort with longer follow‐up would be useful to assess structural changes as well as confirmation of our current findings.