Background Etanercept is a soluble TNF receptor (humanized protein) indicated for the treatment of immune-mediated inflammatory diseases such as rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis (AS), and psoriasis (PsO). Limited information exists on the factors associated with long-term retention and use of etanercept in Canada in a real-world setting.
Objectives To evaluate the 6-year retention rates of etanercept patients in Canada, and to identify factors associated with discontinuation.
Methods A retrospective cohort study was conducted using longitudinal prescription drug claims data from QuintilesIMS Private Drug Plan database (PDP), Ontario Public Drug Plan database (OPDP), and Quebec Public Drug Plan database (RAMQ). Between 07/2008 and 06/2010, bio-naïve patients who initiated etanercept were identified and followed for 72 months. 12-month retention rates were evaluated in 1-year increments for all patients retained on therapy at years 1, 2, 3, 4 and 5 and compared to retention rates in the first year. The covariates associated with time to discontinuation over the entire 72 month period were identified using a Cox proportional hazards regression model.
Results The study identified 4,528 etanercept patients (61% female, 85% rheumatic diseases, and 15% PsO) across Canada who started their therapy during the selection period. Overall, 12-month retention rates on etanercept increased significantly for patients following their first year on therapy (p<.0001), with 66% of patients retained at year 1 vs. 12- month retention rates of 79%, 82%, 84%, 83% and 79% at year 2, 3, 4, 5 and 6, respectively. A total of 17.1% (n=771) of patients were retained for the entire 72 month study. Regression analysis showed PsO patients were less likely to be retained on therapy than other indications (HR 1.199; p<.0001), older patients (65+) were more likely to be retained than younger patients (HR 0.802; p<.0001), and public plan patients (ODB HR 0.735, RAMQ HR 0.55; p<.0001) were more likely to be retained than private plan patients.
Conclusions Etanercept patient retention likelihood increased the more years a patient was retained on therapy. This pattern was consistent across therapeutic areas, sex, age, and payers. Age, indication, and payer were found to have a significant impact in determining etanercept patients' time to therapy discontinuation. With better understanding of factors associated with retention, patient support programs can be designed to address the specific needs of at-risk groups while supporting patients stable on therapy.
Disclosure of Interest M. Khraishi Consultant for: Pfizer Canada and Amgen Canada, Y. Zhang: None declared, J. Ivanovic: None declared, B. Millson: None declared, M.-J. Brabant: None declared, K. Charland: None declared, E. Singh: None declared, J. Woolcott: None declared, H. Jones: None declared