Treatment persistence of subcutaneous TNF inhibitors among Australian patients with immune-mediated rheumatic disease (IMRD)

Introduction: To describe the persistence of treatment with subcutaneous tumor necrosis factor inhibitor (TNFi) adalimumab, etanercept, and golimumab in immune-mediated rheumatic disease (rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis) by treatment sequence (first-line treatment, second-line or further lines of treatment). Methods: A retrospective cohort analysis was conducted using the Australian Commonwealth Department of Human Services Pharmaceutical Benefits Scheme 10% sample data from January 1, 2010, to June 30, 2016. Pharmaceutical Benefits Scheme indications were used to identify patient prescriptions for rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. A patient was considered persistent until a 3-month gap period where a prescription was not dispensed. The 3-month gap interval was chosen because only 1% of all discontinuations occurred beyond this 3-month period. Results: Data from 2,612 first-line patients were included. Treatment discontinuation among first-line patients treated with etanercept or adalimumab was not significantly different from those treated with golimumab (HR 1.10, 95% CI 0.95-1.28, P=0.22; HR 1.06, 95% CI 0.93-1.22, P=0.39; respectively). Among the 1,276 patients in the second-line cohort (etanercept=41%, adalimumab=41%, golimumab=18%) discontinuation was significantly higher for patients on etanercept compared with golimumab (HR 1.24, 95% CI 1.03-1.50, P=0.03); but not for adalimumab compared with golimumab (HR 1.11, 95% CI 0.91-1.34, P=0.31). In the third-line setting, treatment persistence with etanercept was longer than golimumab (HR 0.75, 95% CI 0.59-0.96, P=0.02), but there was no difference between golimumab and adalimumab. Similar findings occurred in the propensity score matched population. Conclusion: Our study shows there is variance in real-world persistence to TNFi in patients with immune-mediated rheumatic disease by line of therapy, with the time on therapy decreasing by line. Australian persistence has been reported at lower overall rates than international evidence.