Real-World Adherence and Drug Survival of Biologics among Patients with Ankylosing Spondylitis

Objectives: The objective of this study was to evaluate the real-world drug survival, adherence, and discontinuation risk of biologics disease-modifying anti-rheumatic drugs (bDMARDs) among patients with ankylosing spondylitis (AS). Methods: This was a retrospective study using a computerized database. Biologic-naïve and biologic-experienced AS patients who initiated treatment with bDMARDs (tumor necrosis factor alpha inhibitors {TNF-αis} or interleukin-17 inhibitor {IL-17i}) during 2015-2018 were included. Adherence was assessed using the proportion of days covered (PDC) method. Drug survival was analyzed using Kaplan-Meier estimates. Risk of discontinuation was estimated by the Cox proportional hazard model. Results: We identified 343 eligible patients utilizing 481 lines of therapy. The mean age was 44.6 years (SD ± 13.4), 57.7% were males, and 69.7% were biologic-naïve at baseline. The proportion of highly adherent patients (PDC ≥ 0.8) in the biologic-naïve group was 63.5% for golimumab, 69.2% for etanercept, and 71.6% for adalimumab (p > 0.9). Among the biologic-experienced group, secukinumab had the highest proportion of adherent patients (75.7%) and etanercept the lowest (50.0%) reaching statistical difference (p < 0.001). The Kaplan-Meier analysis did not show a significant difference in drug survival in either the biologic-naïve or the biologic-experienced groups (p = 0.85). Multivariable analysis demonstrated a similar risk for discontinuation for etanercept, golimumab, and secukinumab compared with adalimumab, regardless of biologic-experience status. Conclusions: Adherence, drug survival, and risk for discontinuation were similar for all TNF-αis and the IL-17i SEC, regardless of biologic-experience status. As drug survival is an indirect measure of drug efficacy, n, in real-world settings, we believe caregivers can integrate these results into treatment considerations.