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.

Objective: To evaluate the long-term clinical and imaging efficacy of etanercept in patients with early, active nonradiographic axial spondyloarthritis (SpA).

Methods: 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.

Results: 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.

Conclusion: 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.