Cost effectiveness of riluzole in amyotrophic lateral sclerosis. Italian Cooperative Group for the Study of Meta-Analysis and the Osservatorio SIFO sui Farmaci.

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 randomised 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 from 313 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, 2.3 months 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.