Background The 3 most common tumor necrosis factor (TNF)-blocker therapies for the treatment of moderate to severe rheumatoid arthritis (RA) are etanercept (ETN), adalimumab (ADA), and infliximab (INF). Treatment patterns (discontinuation, switch, or restart) after TNF-blocker initiation have not been well characterized. RA patients may require dose escalation of TNF-blockers, which may impact costs.
Objectives To describe the real-world utilization and dosing patterns of ETN, ADA, and INF in RA patients in a US managed care population.
Methods In this retrospective analysis, the HealthCore Integrated Research Database was used to identify biologic-naïve, adult (18-64 years) RA patients with ≥1 claim for ETN, ADA, or INF between 1 July 2007 and 31 January 2010 (first claim is index claim). Patients having 6 months pre-index eligibility and 12 months post-index claim were included (study end date 31 January 2011). Patients were excluded if they had any other conditions for which RA biologic therapies were indicated or contraindicated. Therapy persistence, discontinuation, dose escalation, and biologic switch patterns were evaluated. Patients who remained on index TNF-blocker therapy for 1 year without ≥60-day gap were included in the dose escalation analysis, where dose escalation was defined as follows: 50mg to 75mg or 100mg weekly of ETN; 40mg every other week to 40mg weekly of ADA; or increase in vial or decrease in infusion interval to <6 weeks for INF after the fourth infusion (maintenance only).
Results Data from 2426 patients were analyzed (1595 ETN; 417 ADA; 414 INF); mean age was 48.8 yrs, 77% were women. Rates of persistence, discontinuation, switching, and dose escalation are shown (Table). Rates of persistence, switching, and discontinuation were similar between groups (P>0.1 for all 2-way comparisons).
Conclusions Discontinuation and switching patterns within the first year of initiating TNF-blocker therapy were similar among patients receiving ETN, ADA, and INF in a US managed care population. The percentage of patients with a dose escalation was similar to previous studies with lower percentages in patients on ETN than on ADA or INF.
This study sponsored by Immunex, a wholly owned subsidiary of Amgen Inc. and by Wyeth, which was acquired by Pfizer Inc. in October 2009.
Disclosure of Interest M. Fisher Grant/Research support from: Amgen Inc., C. Watson Shareholder of: Amgen Inc., Employee of: Amgen Inc., K. Fox Consultant for: Amgen Inc., Y.-W. Chen Grant/Research support from: Amgen Inc., S. Gandra Shareholder of: Amgen Inc., Employee of: Amgen Inc.