Economic evaluation of etoricoxib versus non-selective NSAIDs in the treatment of ankylosing spondylitis in the UK

Objectives: To evaluate the cost-effectiveness of etoricoxib, a cyclooxygenase (COX)-2 selective inhibitor, versus non-selective nonsteroidal anti-inflammatory drugs (nsNSAIDs) in the treatment of ankylosing spondylitis (AS). Methods: The cost-effectiveness of etoricoxib versus nsNSAIDs was evaluated from the UK National Health Service (NHS) and society perspective with a decision-analytic model, Patients stayed on initial therapy throughout 52 weeks unless they experienced an adverse event (AE) or lacked efficacy, in which case they switched to another nsNSAID or a tumor necrosis factor alpha antagonist. Efficacy data were obtained from a 1-year etoricoxib clinical trial in AS. Bath AS Functional Index (BASFI) data were translated into Quality Adjusted Life Year (OALY) weights using a published data on the relation between BASFI and Short-form (SF) 36 Quality of life scores, as well as the relation between SF-36 and utility. Safety data were based on meta-analyses of etoricoxib trials. Information on treatment pathways, resource consumption, and absenteeism from work was obtained from literature and experts. Model outcomes included QALYs, perforations, ulcers, or bleeds, cardiovascular events, and costs, Results: Etoricoxib was cost-effective compared to nsNSAIDs in terms of cost per QALY saved (5611) pound. Probabilistic sensitivity analysis found a 77% probability of the incremental cost per QALY saved being within a threshold for cost-effectiveness of 20 pound 000. The expected direct costs over the 52-week period were 1.23 pound (95% uncertainty distribution 1.10; pound 1.39) pound and 1.13 pound per day (0.78; pound 1.55) pound for patients starting with etoricoxib and nsNSAIDs, respectively. When costs related to absenteeism were taken into account, the cost per QALY saved was 281 pound. Conclusions: Given the underlying assumptions and data used, this economic evaluation demonstrated that, compared to nsNSAIDs, etoricoxib is a cost-effective therapy for AS patients in the UK.