Cost Effectiveness of Tofacitinib for the Treatment of Active Ankylosing Spondylitis in Greece.

Abstract

Ankylosing spondylitis is a chronic, progressive, inflammatory, multidimensional, musculoskeletal disease primarily involving the axial skeleton. In addition, ankylosing spondylitis is associated with increased morbidity and mortality, significantly affecting productivity and overall quality of life. The aim of the present study was to evaluate the cost effectiveness of tofacitinib compared to currently marketed biologic treatment in patients with active ankylosing spondylitis who have responded inadequately to conventional therapy (biologic-naïve population) or previous biologic therapy (biologic-experienced population) in Greece. A published model comprising a decision tree and a three-state Markov model was adapted from a public payer perspective over a lifetime horizon. Adalimumab and secukinumab, having the highest market shares among biologics for the treatment of ankylosing spondylitis in Greece (standard practice), were selected as comparators in the analysis. Clinical parameters captured treatment response defined per Assessment of Spondyloarthritis International Society 20 response, short-term and long-term changes in Bath Ankylosing Spondylitis Disease Activity Index and Bath Ankylosing Spondylitis Functional Index scores, long-term biologic treatment discontinuation, and adverse events. Efficacy, safety data, and utility values were elicited from the published literature. Direct costs pertaining to drug acquisition, monitoring, adverse events, and disease management costs were considered in the analysis (€2022). Model outcomes were patients' quality-adjusted life-years, total costs, and incremental cost-effectiveness ratios. All future outcomes were discounted at 3.5% per annum. A probabilistic sensitivity analysis was conducted to account for model uncertainty. In a biologic-naïve population, compared with adalimumab, tofacitinib produced an estimated 0.06 additional quality-adjusted life-years [QALYs] (10.67 vs 10.73), at additional costs of €2403 (€147,096 vs €149,500) resulting in an incremental cost-effectiveness ratio of €41,378 per QALY gained. In a biologic-experienced population, the total cost per patient for tofacitinib and secukinumab was estimated to be €151,371 and €145,757, respectively. In terms of health outcomes, tofacitinib was associated with a 0.13 increment in QALYs compared with secukinumab resulting in an incremental cost-effectiveness ratio of €42,784 per QALY gained. The probabilistic sensitivity analysis confirmed the deterministic results for both populations. Tofacitinib was estimated to be a cost-effective option for the treatment of active ankylosing spondylitis in Greece for both biologic-naive and biologic-experienced patients.