Objective: To determine the incremental cost-effectiveness ratios (ICERs) of 2 therapeutic regimens of infliximab for ankylosing spondylitis (AS).
Methods: 230 patients with active AS who were participating in a randomized controlled trial comparing 2 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 (22,388 € vs 17,596 €; p<0.0001), because it required significantly more infliximab infusions per patient (8.4 vs 6.2). The ICERs of the Q6 to DEM regimen were 15,841 € for one ASAS20 response, 23,296 € for one partial remission and 50,760 € 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 50,000 € for one QALY gained.