To determine annual biologic drug and administration costs to the US Veterans Health Administration (VHA) per treated patient with rheumatoid arthritis (RA), psoriasis (PsO), psoriatic arthritis (PsA), or ankylosing spondylitis (AS) who received abatacept, adalimumab, certolizumab pegol, etanercept, golimumab, infliximab, rituximab, tocilizumab, or ustekinumab.
Adults with at least one biologic claim between January 1, 2008 and December 31, 2011 were included. Evidence of enrollment in the VHA was required from 365 days before (pre-index) to 360 days after (post-index) the date of the first biologic claim (index date). Included patients had pre-index diagnoses of RA, PsO, PsA, and/or AS. Drug costs were from Federal Supply Schedule or 'Big Four' in November 2014. Administration costs were VHA fixed costs for infused ($169) and subcutaneous ($25) biologics.
Of the 20,465 patients in the analysis, 10,711 received etanercept, 7838 received adalimumab, and 1196 received infliximab as the index biologic. In these patients, across all uses studied, the VHA incurred greater annual cost per treated patient for infliximab ($18,066) compared with adalimumab ($16,523) and etanercept ($16,526). In the first year post-index, ∼80% of patients were either persistent on these index biologics or re-started these index biologics after a ≥45-day treatment gap. Other biologics comprised <5% of the study population, with sample sizes ranging from 3-374 patients each. Cost by indication for biologics used by >20 patients ranged from $15,056 (etanercept) to $17,050 (abatacept) for RA; $16,697 (adalimumab) to $33,163 (ustekinumab) for PsO; $15,035 (etanercept) to $20,465 (infliximab) for PsA; and $14,239 (etanercept) to $18,536 (infliximab) for AS.
The model was limited to the VHA. Results for biologics other than adalimumab, etanercept, and infliximab were difficult to interpret because of small sample sizes.
Infliximab has higher cost to the VHA than adalimumab or etanercept.