This paper aims to estimate the annual cost of etanercept, adalimumab, and infliximab per treated patient across adult indications using US-managed care drug use data.
Adult patients who used etanercept, adalimumab, or infliximab were identified in the Thomson Reuters MarketScan® Commercial Claims and Encounters Database (Thomson Reuters Healthcare, Ann Arbor, MI, USA) between January 1, 2005 and June 30, 2009. The index event was the first use of etanercept, adalimumab, or infliximab preceded by a diagnosis for rheumatoid arthritis, psoriasis, psoriatic arthritis, or ankylosing spondylitis. Patients were defined as either newly initiating or continuing tumor necrosis factor (TNF) blocker treatment based on their use during the 6 months before the index event. Annual cost per treated patient was the sum of the etanercept, adalimumab, and infliximab medication and administration costs during the 12 months following the index claim. Annual costs were calculated across all patients as well as within each indication group and patient type (new initiator or continuing).
In total, 21,652 patients met the study criteria (etanercept n = 12,065; adalimumab n = 5,685; infliximab n = 3,902); 43% of patients were new initiators. Patient characteristics were similar across treatment groups in terms of age (mean = 49, SD = 10) and gender (66% female). Across indications, the mean annual TNF-blocker cost per treated patient was $15,345 for etanercept, $18,046 for adalimumab, and $24,018 for infliximab. In new initiators, the TNF-blocker cost per treated patient across indications was $14,543 for etanercept, $16,978 for adalimumab, and $21,086 for infliximab; among patients continuing therapy, annual costs were $15,836 for etanercept, $19,457 for adalimumab, and $25,748 for infliximab.
Patients on etanercept had the lowest TNF-blocker cost per treated patient for adult indications when applying actual drug use from a US-managed care population. TNF-blocker costs per treated patient on adalimumab and infliximab were approximately 18% and 57% higher than etanercept, respectively, using real-world drug use data.