Cost‑effectiveness analysis of anti‑influenza drugs in adult outpatient settings in Japan

The loss of productivity due to influenza virus (flu) infections (3 to 5
million cases globally), which can sometimes amount to as much as five
working days, is a major socioeconomic issue. This study compares
baloxavir marboxil’s cost-effectiveness with that of oseltamivir for
influenza treatment in adult outpatient settings in Japan from the
healthcare-payer perspective. A decision tree model was constructed with
probabilities from CAPSTONE 1 for low-risk patients and CAPSTONE 2 for
high-risk patients. Direct costs included medical costs and drug prices.
Medical costs were obtained from the Japanese Medical Fee Index (2019
version). Effectiveness outcomes (quality-adjusted life-year [QALY]) were
measured using the EQ-5D-5L questionnaire for adult patients who
previously experienced flu infection. The time horizon was 14 days.
Deterministic and probabilistic sensitivity analyses were performed to
examine the robustness of the results. The base case analysis revealed
oseltamivir dominated baloxavir marboxil for low-risk patients. However,
the incremental cost-effectiveness ratio (ICER) for high-risk patients
with body weight < 80 kg was 3,178,163 yen/QALY (US$ 30,905/QALY),
which was less than the willingness to pay 5,000,000 yen/QALY (US$
48,621/QALY).  Moreover, the ICER for high-risk patients with
influenza and body weight ≥ 80 kg was 10,709,187 yen/QALY (US$
104,139/QALY). The study revealed baloxavir marboxil was more
cost-effective than oseltamivir for high-risk patients with body weight
< 80 kg. As the concept of a formulary in hospitals has gradually
become popular, healthcare providers may find the insights from this study
helpful in developing a novel formulary for decision-makers to consider.