Comparison of Healthcare Costs Between Rheumatoid Arthritis Patients Treated with Infused Biologics After Switching from Another Biologic

Introduction: While there is a substantial body of literature on the comparative healthcare costs of biologics used to treat rheumatoid arthritis (RA), nearly all of these investigations have been exclusively focused on anti-tumor necrosis factor-α (anti-TNF) agents in the setting of first-line biologic treatment. This study compared healthcare costs between RA patients treated with infused biologics after previously using at least one other biologic agent.

Methods: Using a large US administrative claims dataset, adult RA patients initiating an infused biologic (abatacept, infliximab, tocilizumab) between January 1, 2010 and January 1, 2012 (initiation = index) were identified. Rituximab was excluded because of unique dosing intervals, which make it difficult to determine treatment discontinuation using a claims database. Patients were required to have used one or more other biologic (infused or injected) at any time before index. Patients could contribute multiple observations to the dataset; one for each infused biologic they initiated between January 1, 2010 and January 1, 2012. A 6-month period before index was used to measure patient characteristics. A variable-length follow-up period after index was used to measure per-patient per-month (PPPM) healthcare costs, including biologic costs, RA-related healthcare costs, and all-cause healthcare costs. Generalized estimating equations models compared healthcare costs between the biologic agents, adjusting for patients' demographics and clinical characteristics.

Results: The sample comprised 3,771 infused biologic initiations (abatacept = 1,759; infliximab = 922; tocilizumab = 1,090); the mean age of participants was 55 years, 82 % were female, and the median follow-up ranged from 251 to 280 days. Compared with other patients, patients treated with tocilizumab had significantly lower (all P < 0.05) PPPM biologic costs (abatacept = $2,597, infliximab = $3,141, tocilizumab = $1,894), RA-related healthcare costs (abatacept = $2,929, infliximab = $3,598, tocilizumab = $2,236), and all-cause healthcare costs (abatacept = $3,735, infliximab = $4,600, tocilizumab = $3,042).

Conclusions: Among RA patients treated with infused biologics after previously using at least one other biologic, patients treated with tocilizumab had the lowest real-world healthcare costs, largely driven by lower costs directly related to biologic treatment. Such biologic-related cost differences may be driven by variations in real-world treatment patterns (e.g., dose, escalation, treatment frequency).