Cost-Effectiveness Analysis of Isavuconazole vs. Voriconazole as First-Line Treatment for Invasive Aspergillosis

INTRODUCTION Invasive aspergillosis (IA) is associated with a significant clinical and economic burden. The phase III SECURE trial demonstrated non-inferiority in clinical efficacy between isavuconazole and voriconazole. No studies have evaluated the cost-effectiveness of isavuconazole compared to voriconazole. The objective of this study was to evaluate the costs and cost-effectiveness of isavuconazole vs. voriconazole for the first-line treatment of IA from the US hospital perspective. METHODS An economic model was developed to assess the costs and cost-effectiveness of isavuconazole vs. voriconazole in hospitalized patients with IA. The time horizon was the duration of hospitalization. Length of stay for the initial admission, incidence of readmission, clinical response, overall survival rates, and experience of adverse events (AEs) came from the SECURE trial. Unit costs were from the literature. Total costs per patient were estimated, composed of drug costs, costs of AEs, and costs of hospitalizations. Incremental costs per death avoided and per additional clinical responders were reported. Deterministic and probabilistic sensitivity analyses (DSA and PSA) were conducted. RESULTS Base case analysis showed that isavuconazole was associated with a $7418 lower total cost per patient than voriconazole. In both incremental costs per death avoided and incremental costs per additional clinical responder, isavuconazole dominated voriconazole. Results were robust in sensitivity analysis. Isavuconazole was cost saving and dominant vs. voriconazole in most DSA. In PSA, isavuconazole was cost saving in 80.2% of the simulations and cost-effective in 82.0% of the simulations at the $50,000 willingness to pay threshold per additional outcome. CONCLUSION Isavuconazole is a cost-effective option for the treatment of IA among hospitalized patients. FUNDING Astellas Pharma Global Development, Inc.