Etanercept and adalimumab treatment patterns in psoriatic arthritis patients enrolled in a commercial health plan.

INTRODUCTION: Treatment patterns, including persistence, gaps in therapy, switching, and discontinuation, were examined in patients with psoriatic arthritis (PsA) who received the tumor necrosis factor (TNF)-blockers etanercept or adalimumab.

METHODS: This retrospective study utilized administrative claims data from a United States commercial health plan. Adults (age 18-64 years) with PsA who started therapy with etanercept or adalimumab as index therapy between January 1, 2006 and December 31, 2008 were included in the analysis. Patients were continuously enrolled in the health plan for at least 6 months before and at least 12 months after the start of index therapy. Initial TNF-blocker dose and rates of therapy persistence (continuous use of index medication without a gap of at least 60 days), therapy gaps, and discontinuation (gap in therapy of at least 60 days) were estimated. Those who discontinued were further classified as: (1) discontinued all biologic therapy, (2) restarted index medication, (3) switched to another biologic therapy, or (4) other.

RESULTS: A total of 346 patients with PsA (202 etanercept, 144 adalimumab) were eligible. Most (90.6% etanercept; 88.9% adalimumab) started index therapy at the labeled dose. Persistence with index therapy for 12 months was observed in 50% of patients on etanercept and 45% of patients on adalimumab (P = 0.37). Patients on etanercept had a longer duration of persistence (434 vs. 353 days; P = 0.02), more pauses of at least 7 days (4.7 vs. 3.5; P = 0.004), and a longer mean pause length (48.6 vs. 29.3 days; P = 0.01) than patients on adalimumab. Of patients who discontinued (24.8% etanercept; 35.1% adalimumab), 46.4% and 41.5% restarted etanercept and adalimumab, respectively; 24.8% and 35.1% discontinued all TNF-blockers; 20.0% and 19.2% switched to another biologic; and 8.8% and 4.3% had other therapy changes.

CONCLUSIONS: Approximately half of PsA patients were persistent on their index TNF-blocker for 12 months. Pauses in therapy and therapy discontinuation were common, but more than 40% of patients restarted their index TNF-blocker after discontinuation.