Background Multiple biologic agents are approved treatments for moderate to severe RA. However, they differ in mechanism of action, mode of administration, dosing ranges and dosing frequency. In order to compare actual costs of these agents, it is important to capture drug usage from clinical practice. This study describes annual costs of biologics per treated patient with RA using drug utilization data from a US commercially-insured population.
Objectives To estimate annual cost per treated patient for etanercept, adalimumab, infliximab, abatacept, rituximab, golimumab, and certolizumab in RA using US claims data.
Methods The MarketScan Commercial Database was used to identify patients (18-63 years of age) with ≥1 claim for a biologic of interest between Jan 1, 2008 and Dec 31, 2010 preceded by at least 6-months of enrolment and a diagnosis of RA. The Commercial Database contains inpatient, outpatient, and prescription drug experience of several million employees and their dependents (annually), covered under a variety of fee-for-service and capitated health plans, including exclusive provider organizations, PPOs, POS plans, indemnity plans, and health maintenance organizations (HMOs). The first drug claim meeting these criteria defined the index date and biologic. “Continuing” patients had a claim for the same biologic before their index date; “New” patients did not. Patients were required to be continuously enrolled for 1-year following the index claim. Patients with a claim for psoriasis, psoriatic arthritis, ankylosing spondylitis, Crohn’s disease, or ulcerative colitis pre-index were excluded since not all biologics are approved for these indications. Mean monthly dose and total dose of other biologics after discontinuation of their index biologic was calculated for the 12-months after index. US Wholesale Acquisition Costs (WAC) as of Jan 2013 and the Medicare Physician Fee Schedules were applied to the mean monthly dose and related drug administration to calculate cost per treated patient.
Results A total of 38,026 patients were included, 88% received etanercept, adalimumab, or infliximab. Patient characteristics were similar across groups; mean age 49.9 years (SD 9.3), 78% female. For all agents other than certolizumab, persistence was higher for continuing patients. Annual cost per treated patient for new and continuing patients are shown in Table 1.
Conclusions Of the three most commonly prescribed biologics for RA, etanercept has a lower cost per treated patient than adalimumab or infliximab overall. Agents with other mechanisms of action had lower costs per treated patient than TNF-blockers, however usage was relatively uncommon, 6.6% abatacept and 3.5% rituximab and the choice of those agents may be influenced by disease severity and other patient characteristics not captured in claims data.
Acknowledgements Research funded by Immunex Corporation, a wholly owned subsidiary of Amgen Inc., and by Wyeth, which was acquired by Pfizer Inc. in October 2009.
Disclosure of Interest M. Bonafede: None Declared, G. Joseph Shareholder of: Amgen Inc., Pfizer Inc., Employee of: Amgen Inc., N. Princic: None Declared, D. Harrison Shareholder of: Amgen Inc., Employee of: Amgen Inc.