Persistence to Biologic Therapy Among Patients With Ankylosing Spondylitis: An Observational Study Using the OPAL Dataset

Objective: To describe the treatment response and persistence to biologic disease-modifying antirheumatic drug (bDMARD) therapy in patients with ankylosing spondylitis (AS) in a real-world Australian cohort.

Methods: This was a retrospective, noninterventional cohort study that extracted data for patients with AS from the Optimising Patient outcomes in Australian RheumatoLogy (OPAL) dataset for the period of August 2006 to September 2019. Patients were classified as either bDMARD initiators if they commenced a bDMARD during the sampling window, or bDMARD-naïve if they did not. Results were summarized descriptively. Treatment persistence was calculated using Kaplan-Meier methods. Differences in treatment persistence were explored using log-rank tests.

Results: There were 5048 patients with AS identified. Of these, 2597 patients initiated bDMARDs and 2451 remained bDMARD-naïve throughout the study window. Treatment with first-, second-, and third-line bDMARDs significantly reduced disease activity. Median persistence on first-line bDMARDs was 96 months (95% CI 85-109), declining to 19 months (95% CI 16-22) in second-line therapy, and 15 months (95% CI 11-18) in third-line therapy. Median persistence was longest for the golimumab (GOL) group in all lines of therapy and shortest for the etanercept (ETN) group. Differences in persistence rates according to the time period that bDMARDs were prescribed (pre- and post-2012) were also seen for ETN and adalimumab.

Conclusion: In this cohort, all bDMARDs effectively reduced AS disease activity. Treatment persistence was sustained for up to 8 years for patients remaining on their first bDMARD, longer than on subsequent agents. Further research is needed to determine its influence on treatment recommendations.