Cost-utility analysis of isavuconazole compared with the standard of care as a first-line therapy for patients with invasive fungal infection prior to differential pathogen diagnosis in Japan

This study aimed to evaluate the cost-effectiveness of isavuconazole compared with voriconazole as a first-line therapy for patients with invasive aspergillosis prior to differential pathogen diagnosis. Using a state-transition model, a cost-utility analysis of isavuconazole compared with voriconazole was conducted in patients with presumptive invasive aspergillosis. The study population consisted of patients with hematological malignancies undergoing hematopoietic stem cell transplantation (HSCT) or chemotherapy who developed invasive fungal infections. The incremental cost-effectiveness ratio (ICER) was analyzed from the perspective of public healthcare. In patients with presumptive invasive aspergillosis, 6.6% were assumed to have mucormycosis. Efficacy data were sourced from the SECURE and VITAL trials, which included patients with invasive aspergillosis and mucormycosis. Expected survival was based on data for acute myeloid leukemia. The cost of voriconazole was based on its generic price. Different parameters were set for quality of life, expected survival period, and hospitalization costs in the HSCT and chemotherapy models, and the robustness of the model was evaluated using probabilistic and deterministic sensitivity analyses. In the HSCT model, the base case showed an incremental quality-adjusted life-years (QALYs) of 0.37 and an incremental cost of JPY 918,682 for isavuconazole compared with voriconazole, with an ICER of JPY 2,515,813. In the chemotherapy model, the incremental QALYs was 0.16, and the incremental cost was JPY 723,111, with an ICER of JPY 4,411,564. The probability sensitivity analysis showed that the proportion of ICERs below JPY 5 million was 100.0% in the HSCT model and 79.1% in the chemotherapy model. Reference efficacy data were obtained from non-Japanese clinical trials. Assuming a willingness-to-pay threshold of JPY 5 million for additional QALYs, isavuconazole was shown to be cost-effective compared with voriconazole in both the HSCT and chemotherapy models as a first-line therapy for patients with presumptive invasive aspergillosis.