Treatment Patterns and Annual Drug Costs of Biologic Therapies Across Indications from the Humana Commercial Database

BACKGROUND: A variety of biologic therapies are currently used for the treatment of inflammatory autoimmune diseases, including rheumatoid arthritis (RA), psoriasis (PsO), psoriatic arthritis (PsA), and ankylosing spondylitis (AS). These diseases require long-term treatment, and information regarding the use and costs of biologic therapies can be valuable in making treatment and formulary decisions for clinicians and payers. OBJECTIVES: To evaluate current utilization and annual costs of biologic therapies for treatment of RA, PsO, PsA, and AS in a real-world setting. METHODS: This retrospective observational cohort analysis utilized data from the Humana commercial claims database. Eligible patients had an index (first) claim between February 1, 2008, and September 30, 2011, for abatacept, adalimumab, certolizumab pegol, etanercept, golimumab, infliximab, rituximab, or ustekinumab and a diagnosis of RA, PsO, PsA, AS, or combination of these diseases. Patients with and without a claim for their index therapy within 180 days prior to their index dates were defined as continuing and new patients, respectively. Outcomes included 1-year rates of persistence; rates of restarting, discontinuing, or switching for patients who were not persistent; and annual costs. Costs were based on dose and the October 2013 wholesale acquisition cost (WAC). Total expenditure was calculated as the (total index biologic drug utilization × WAC) + (number of administrations × Medicare fee schedule) + Σ(biologic dose after discontinuation × associated WAC price). RESULTS: Of 2,721 patients analyzed, 1,308 (48%) were new patients, and 1,413 (52%) were continuing patients. Across approved indications, the most commonly used biologics were adalimumab, etanercept, and infliximab. Continuing patients had higher rates of persistence on index therapy than new patients. The mean annual cost [SD] per treated patient for new patients across all indications was numerically lowest for adalimumab ($20,916 [$7,572]), followed by infliximab ($22,516 [$8,460]) and etanercept ($23,567 [$8,314]). The mean annual cost [SD] per treated patient for continuing patients across all indications was numerically lowest for etanercept ($21,508 [$6,769]), followed by infliximab ($22,852 [$11,674]) and adalimumab ($24,341 [$8,906]). CONCLUSIONS: The tumor necrosis factor blockers adalimumab, etanercept, and infliximab were the most commonly used biologics across indications. New patients were less persistent than those continuing on therapy. Among new patients, adalimumab had the lowest mean annual cost per treated patient, and etanercept had the lowest mean annual cost per treated patient among those continuing on therapy.