Tumor Necrosis Factor Inhibitor Discontinuation in Patients with Ankylosing Spondylitis: An Observational Study From the US-Based Corrona Registry

INTRODUCTION: Tumor necrosis factor inhibitors (TNFis) have shown efficacy for the treatment of ankylosing spondylitis (AS). However, many patients may discontinue or switch TNFis due to lack of effect or adverse events. As biologics with alternative mechanisms of action become available for the treatment of AS, it is important to better understand the characteristics of patients who discontinue or have an inadequate response to TNFis to help inform treatment choices regarding initiating or switching to a biologic therapy. This study compared demographic and clinical characteristics of patients with AS who discontinued vs. continued a TNFi by their second follow-up visit in the US-based Corrona Psoriatic Arthritis and Spondyloarthritis (PsA/SpA) Registry. METHODS: All patients aged ≥ 18 years with AS enrolled in the Corrona PsA/SpA Registry between April 2013 and January 2015 who were receiving or had initiated a TNFi (index therapy) at the time of registry enrollment (baseline) and had ≥ 2 follow-up visits were included. Patient demographics, clinical characteristics, and patient-reported outcome scores at baseline were compared between cohorts of patients who discontinued or continued their TNFi by the second follow-up visit. RESULTS: Of the 155 included patients, 37 (23.9%) discontinued their index TNFi therapy by the second follow-up visit (mean follow-up, 17.8 months). Patients who discontinued their TNFi were older (mean age, 52.1 vs. 46.6 years; P = 0.04), were more likely to be obese (59.5% vs. 34.2%; P < 0.01), and had worse mean Bath Ankylosing Spondylitis Disease Activity Index and Bath Ankylosing Spondylitis Functional Index scores (4.8 vs. 3.5 and 4.2 vs. 2.8, respectively; P = 0.01 for both) at baseline than those who continued their TNFi. CONCLUSIONS: The results of this real-world study provide insight into the demographic and clinical characteristics of patients with AS who discontinue vs. continue TNFi therapy in US clinical practice. FUNDING: Corrona, LLC. PLAIN LANGUAGE SUMMARY: Plain language summary available for this article.