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Etanercept and Ustekinumab Dosing for Psoriasis and Psoriatic Arthritis

For patients with psoriasis and/or psoriatic arthritis, actual-to-expected dosing ratios and costs were lower for etanercept than for ustekinumab.
Published Online: Sep 21,2017
Machaon Bonafede, PhD, MPH; Derek H. Tang, PhD, BSPharm; Kathleen Wilson, MPH; Alice Huang, MS; David J. Harrison, PhD; and Bradley S. Stolshek, PharmD
ABSTRACT

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.

                                                                                         Am J Pharm Benefits. 2017;9(5):150-154

Actual use of medications is important for payers to predict the cost of a treatment. Low variation between actual versus expected dosing can reduce the uncertainty of drug expenses, which can be beneficial from the payer’s budgeting perspective. There is a lack of evidence on actual dosing versus expected dosing patterns and costs of biologic therapies used for psoriasis and/or psoriatic arthritis. Drugs that possess the combined characteristics of low expected cost and minimal uncertainty of such cost would be optimal to payers.

Etanercept (a tumor necrosis factor inhibitor) and ustekinumab (an interleukin [IL]-12 and IL-23 blocker) are commonly used biologic therapies for the treatment of moderate to severe plaque psoriasis, with both drugs being efficacious in treating psoriatic arthritis. Etanercept for psoriasis is administered subcutaneously (SC) at a starting dose of 100 mg/week for 12 weeks followed by a maintenance dose of 50 mg/week.1 Ustekinumab is administered SC based on weight: 45 mg for patients weighing ≤100 kg (220 lbs) and 90 mg for patients >100 kg, with the first 2 doses 4 weeks apart followed by a dose every 12 weeks.2 These biologics are expected to be generally representative of biologics used to treat plaque psoriasis that use standard dosing and weight-based dosing.

A study by Thayer et al that examined actual versus expected dosing with etanercept showed that patients with psoriasis and/or psoriatic arthritis used 89% to 107% of the expected dose based on claims data from 2003 to 2008.3 This wide range was dependent on whether dosing was based on the psoriasis or psoriatic arthritis indication. Actual versus expected dosing patterns and costs for ustekinumab or other biologics used to treat moderate to severe plaque psoriasis have not been reported to date. The objective of this study was to estimate current actual dosing of etanercept and ustekinumab in patients with psoriasis and/or psoriatic arthritis and compare it with the recommended dosing in the US Package Inserts (USPIs), and to estimate annual psoriasis-related costs.

METHODS

Data Source

Data for this analysis were obtained from the Truven Health MarketScan Commercial Claims and Encounters Database. This database contains the annual inpatient, outpatient, and outpatient prescription drug experience of 30 million commercially insured US patients. Enrollees are covered under a variety of fee-for-service and managed care health plans, including exclusive provider organizations, preferred provider organizations, point-of-service health insurance plans, indemnity plans, and health maintenance organizations.

Study Design

This was a retrospective, observational cohort study based on US administrative claims data from the Truven Health MarketScan® Commercial Database. Data were collected from January 1, 2010, through December 31, 2013 (Figure 1). The first new claim for etanercept or ustekinumab (index agent) between January 1, 2011, and December 31, 2012, was the index event/date. The baseline period comprised the 12 months prior to the index date, and the follow-up period was the 12 months after the index date. Patients were new to any biologic and had no outpatient medical claim or prescription claim for any biologic approved prior to initiation of the index agent.




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