Objective: To determine the incremental cost-effectiveness ratios (ICERs) of two therapeutic regimens of infliximab for ankylosing spondylitis (AS).
Methods: 230 patients with active AS who were participating in a randomised controlled trial comparing two infliximab infusion modalities-every 6 weeks (Q6) and on demand (DEM)-were included in an economic evaluation within the trial. Data were collected by phone every 3 months for 1 year. Direct and indirect costs were calculated from a payer perspective. Health-related quality of life was assessed with a general health rating scale. ICERs were calculated for one 20% improvement (ASAS20), for one partial remission and for one quality-adjusted life year (QALY) gained.
Results: The Q6 regimen was significantly more efficacious than the DEM regimen but also more costly (euro22 388 vs euro17 596; p<0.001), because it required significantly more infliximab infusions per patient (8.4 vs 6.2). The ICERs of the Q6 to DEM regimen were euro15 841 for one ASAS20 response, euro23 296 for one partial remission and euro50 760 for one QALY gained.
Conclusion: The administration of infliximab every 6 weeks is cost effective as compared with a DEM regimen; however, the ICER is close to the acceptability threshold of euro50 000 for one QALY gained.
Trial registration number: NCT 00439283.
Trial registration: ClinicalTrials.gov NCT00439283.