Background: Infliximab is an anti-tumour necrosis factor monoclonal antibody, which significantly improves pain, stiffness and functional disability outcomes in patients with active ankylosing spondylitis. There are limited data available on the efficacy of this treatment for the subgroup with established spinal ankylosis.
Aim: To compare the treatment response of infliximab in active severe ankylosing spondylitis for patients with and without radiographic evidence of spinal ankylosis in the clinical practice setting.
Methods: Twenty-seven patients with mean Bath Ankylosing Spondylitis Disease Activity Index of 8.7, all HLA-B27 positive, with 11 (41%) having spinal ankylosis, were studied for 54 weeks. The qualification for initial and ongoing infliximab treatment was defined by the Australian Pharmaceutical Benefit Schedule (PBS), and 5 mg/kg of infliximab was given at 0 week (baseline), repeated at 2 and 6 weeks and every 6 weeks thereafter. At each time point, PBS-mandated and international consensus response measures were completed. Disease activity and outcome measures for spinal ankylosis subgroup and those who did not have spinal ankylosis were cross-sectionally compared at baseline and 1 year.
Results: Patients with spinal ankylosis tended to be older (P = 0.01). Although the subgroup with spinal ankylosis had higher baseline activity scores, the only significant difference between the subgroups was the degree of morning stiffness (P = 0.04). By 54 weeks, all patients including the subgroup with spinal ankylosis fulfilled the PBS criteria for continuation of treatment. Majority of patients including the subgroup with spinal ankylosis achieved the various international consensus response measures. Patients with spinal ankylosis also experienced significant improvements in health-related quality of life, with majority returning to full-time employment by 1 year.
Conclusion: In real-life clinical practice, patients with established disease with spinal ankylosis and high levels of inflammation and disease activity can achieve a major clinical response with infliximab.