Effects of Long‐Term Etanercept Treatment on Clinical Outcomes and Objective Signs of Inflammation in Early Nonradiographic Axial Spondyloarthritis: 104‐Week Results From a Randomized, Placebo‐Controlled Study

To evaluate the long‐term clinical and imaging efficacy of etanercept in patients with early, active nonradiographic axial spondyloarthritis (SpA). Adult patients who satisfied the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial SpA (but not the modified New York radiographic criteria), with symptom duration >3 months to <5 years, and who were unresponsive to ≥2 nonsteroidal antirheumatic drugs (NSAIDs) received double‐blind etanercept 50 mg/week or placebo for 12 weeks, followed by open‐label etanercept 50 mg/week to week 104. Clinical, magnetic resonance imaging (MRI; Spondyloarthritis Research Consortium of Canada [SPARCC] scores), and safety outcomes at 104 weeks were analyzed. Of 215 randomized patients (etanercept: n = 106; placebo: n = 109), 205 entered the study (etanercept/etanercept: n = 100; placebo/etanercept: n = 105) and 169 completed the open‐label period (etanercept/etanercept: n = 83; placebo/etanercept: n = 86). At week 104, 61 of 81 (75%), 49 of 81 (61%), 48 of 80 (60%), and 57 of 81 (70%) patients who received etanercept throughout the trial achieved ASAS20, ASAS40, Ankylosing Spondylitis Disease Activity Score (ASDAS) inactive disease, and Bath Ankylosing Spondylitis Disease Activity Index criteria for 50% improvement (BASDAI 50) scores, respectively (observed). From baseline to week 104, continued improvements in clinical outcomes (ASDAS–C‐reactive protein: −1.5 and −1.7; BASDAI: −3.3 and −3.8 [last observation carried forward]), and SPARCC MRI scores (sacroiliac joint: −6.0 and −3.4; spinal: −2.1 and −0.8 [observed]) were seen in patients receiving etanercept/etanercept and placebo/etanercept. During the study, 8% in the etanercept/etanercept group and 7% in the placebo/etanercept group had serious adverse events; no new safety signals were seen. Patients with early, active nonradiographic axial SpA and an inadequate response to at least 2 NSAIDs demonstrated improvement in clinical and imaging outcomes that were sustained through 104 weeks of etanercept treatment.