Cost-Effectiveness Analysis of Influenza Treatments in Japan Using a Transmission Model: The Impact of Baloxavir and Oseltamivir Shares.

Abstract

Introduction: Influenza is a highly transmissible respiratory viral infection, with a risk of severe complications and excess respiratory mortality. Clinical trial data showed that baloxavir was more effective than oseltamivir for reducing duration of virus shedding, which is a key predictor of transmission. Consideration of the effect of treatments on transmission rates is important to ensure that the value of treatments is captured. This study assessed the cost-effectiveness of different treatment strategies with baloxavir and oseltamivir, considering their impact on influenza transmission.

Methods: The analysis used two models: a dynamic transmission model to estimate influenza incidence, with outputs incorporated in a static population-level decision tree model, in order to evaluate the clinical outcomes and cost-effectiveness of treatment strategies with different shares of baloxavir and oseltamivir from the healthcare payer's perspective in Japan. Clinical data were sourced from phase 3 trials, and cost inputs were informed by the Ministry of Health, Labour and Welfare, as well as JammNet. Sensitivity and scenario analyses were also conducted.

Results: Increasing the use of baloxavir in adults from 40% to 50% reduces the number of influenza cases by 17%, hospitalizations by 18%, and deaths by 23%, with cost savings of JPY (Japanese yen) 16,280 million and 10,486 quality-adjusted life years (QALYs) gained, in the total population in Japan. Across all risk and age subgroups, increasing the share of baloxavir was cost-saving and more effective, and, therefore, was considered dominant, which was also confirmed by the sensitivity analysis.

Conclusion: Treatment of influenza with baloxavir is anticipated to offer value for money within Japan's healthcare system, delivering significant clinical benefits both for the general population and for all age and risk groups. Accounting for the treatment's impact on influenza transmission adds another dimension of value and further reinforces the evidence supporting the growing use of baloxavir in Japan.