Cost Effectiveness of Riluzole in Amyotrophic Lateral Sclerosis

Abstract

Objective: In patients with amyotrophic lateral sclerosis, long term treatment with riluzole has been reported to improve survival or tracheostomy-free survival in comparison with placebo. We conducted a pharmacoeconomic analysis for estimating the cost per life-year gained using this drug. Design: This study was an incremental cost-effectiveness lifetime analysis. Setting: The clinical material was derived from 2 placebo-controlled randomized controlled trials comparing riluzole versus usual care without riluzole, which were identified through a literature search based on the IOWA and the Medline systems. Patients and interventions: The study included 633 patients with amyotrophic lateral sclerosis. Patient-level information was retrieved from313 patients treated with riluzole and 320 patients assigned to placebo. Survival after randomisation was compared between the 2 groups using standard statistics (log-rank test and Cox analysis), whereas the lifetime survival gain was estimated using Gompertz extrapolation. Cost data relative to the expenditure for healthcare resources were obtained from published information (using the US average wholesale price for the acquisition cost of riluzole). Sensitivity testing assessed the impact of different cost-of-illness assumptions for treated and untreated patients. Main outcome measures and results: Our primary analysis showed that treatment with riluzole significantly prolonged survival [death risk = 0.77; 95% confidence interval (CI): 0.62 to 0.96; p = 0.022]. The lifetime survival gain (including 3% annual discounting) was, on average, 2.3months per patient, while the incremental cost was around $US12 000 per patient. Hence, the cost-effectiveness ratio of riluzole versus usual care without riluzole was $US62 609 per life-year gained (discounted dollars per discounted years; 95%CI: $US13 458 to $US205 714). The sensitivity analysis, considering different values of national cost for riluzole, suggested an interval for this parameter ranging from $US45 048 to $US62 609. Conclusions: Our study indicates that in patients with amyotrophic lateral sclerosis, riluzole has an unfavourable cost-effectiveness ratio or, at best, a borderline pharmacoeconomic profile.