Efficacy of etanercept in the treatment of the entheseal pathology in resistant spondylarthropathy - A clinical and magnetic resonance imaging study

Objective. To determine the effect of tumor necrosis factor alpha (TNF alph a) blockade with etanercept on the clinical manifestations of resistant spo ndylarthropathy (SpA) and on axial and peripheral entheseal lesions using m agnetic resonance imaging (MRI). Methods. We performed a descriptive longitudinal study of 10 SpA patients, all of whom had active inflammatory back pain and peripheral involvement. P atients were treated with 25 mg subcutaneous etanercept twice weekly for 6 months. Clinical assessments included entheseal count, visual analog scale (VAS) scores for spinal pain during the day and night, VAS scores for enthe seal pain, the Bath Ankylosing Spondylitis Functional Index (BASFI), the Ba th Ankylosing Spondylitis Disease Activity Index (BASDAI), and the Ankylosi ng Spondylitis Quality of Life (ASQoL) questionnaire. MRI scans of sacroili ac (SI) joints, the lumbar spine, and affected peripheral joints were perfo rmed using a 1.5T scanner employing T1-weighted, T2-weighted fat-suppressed (FS), and T1-weighted FS postgadolinium sequences at baseline and at 6 mon ths. Enthesitis and associated osteitis were scored semiquantitatively in p re- and posttreatment scans. Results. There was a statistically significant improvement in all clinical and functional parameters (P = 0.008 for VAS spinal pain score during the d ay and for VAS spinal pain score during the night, P = 0.008 for the BASFI, and P = 0.005 for the BASDAI) as well as in quality of life (P = 0.005 for the ASQoL) at 6 months. Nine patients had a total of 44 MRI-detectable ent heseal lesions. These were seen in the SI joints in 6 patients (n = 15 lesi ons), in the lumbar or cervical spine in 9 patients (n = 22 lesions), and i n peripheral joints in 5 patients (n = 7 lesions). Overall, 86% of MRI-dete cted entheseal lesions either regressed completely or improved. No new lesi ons developed. Conclusion. These findings suggest that TNF alpha blockade with etanercept is markedly effective in controlling the clinical manifestations of SpA tha t is resistant to disease-modifying antirheumatic drugs. This is associated with marked improvement of enthesitis and associated osteitis pathology as determined by MRI.