Hospital Budget Impact and Provider-Side Economic Evaluation of Lecanemab and Donanemab Under Japan's National Fee...

The study aimed to assess the provider-side financial viability of antiamyloid disease-modifying therapies for early Alzheimer's disease in Japan, we developed a linear hospital-provider model that separates a short inpatient diagnostic phase from an outpatient infusion phase.

Using public National Health Insurance tariffs, official 2025 drug prices, and workflow-based labor costing with time-driven activity-based costing, we estimated per-case outpatient margins and program-level break-even case volumes. Scenarios examined fee-for-service versus diagnosis procedure combination/per-diem payment system hospitals, magnetic resonance imaging surveillance intensity, purchase discounts, wage growth, routine-workflow staff time, and the scheduled 15% lecanemab price reduction effective November 1, 2025.

At 1.5 T with no assumed wage growth, donanemab yielded positive outpatient margins from + 37,670JPY at no purchase discount to + ¥110 777 at a 2.6% discount. Lecanemab at 50 kg yielded -¥9048 at no discount and broke even at a discount of 0.304% before the scheduled price reduction and 0.358% after it. At 55 to 60 kg, the equal-discount threshold at which lecanemab overtook donanemab shifted from about 6.2% before the price reduction to 20.9% after it. Sensitivity analyses showed purchase discounts were the dominant driver, whereas labor and workflow inputs affected lecanemab more because it requires more infusions per year.

Under Japan's fee schedule, both therapies were financially viable across typical purchase-discount ranges in scenario analyses, but findings should be interpreted as provider-margin estimates rather than comparative clinical judgments.