Etanercept and Ustekinumab Dosing for Plaque Psoriasis and Psoriatic Arthritis

Objectives: To compare estimated actual dosing of etanercept and ustekinumab in patients with psoriasis and/or psoriatic arthritis with recommended dosing, and to estimate annual cost of these psoriasis treatments. Study Design: Retrospective, observational cohort study. Methods: Administrative claims data from a commercial claims database from January 1, 2010, through December 31, 2013, were analyzed. Patients had a diagnosis of psoriasis and/or psoriatic arthritis, and continuous enrollment with medical and pharmacy benefits for the 12-month preindex period and the 12-month post index follow-up period. Dosing was determined with actual-to-expected dose ratios computed while patients were persistent to therapy. Expected dose was calculated according to US Package Inserts; expected weight-based dosing of ustekinumab was estimated using random weight assignment based on starting dose. Annual psoriasis-related costs consisting of biologics, nonbiologic psoriasis therapies, and psoriasis- related healthcare utilization were calculated. Results: Data from 2997 patients (2128 etanercept, 869 ustekinumab) were analyzed. Actual-to-expected dose ratios (SD) for etanercept and ustekinumab were 0.939 (0.304) and 1.169 (0.687), respectively, for all patients; 1.012 (0.295) and 1.164 (0.666) for patients with psoriasis but without psoriatic arthritis; and 0.783 (0.261) and 1.203 (0.813) for patients with psoriatic arthritis. Annual costs (SD) for all patients were $28,291 ($13,296) and $37,537 ($17,209) for etanercept and ustekinumab, respectively; for psoriasis patients without psoriatic arthritis, they were $29,712 ($13,988) and $ 36,976 ($ 16,817), respectively; and for patients with psoriatic arthritis, they were $ 25,246 ($ 11,084) and $ 41,068 ($ 19,199), respectively. Conclusions: Actual-to-expected dosing ratios and annual costs were lower for etanercept than for ustekinumab in patients with psoriasis and/or psoriatic arthritis.