OBJECTIVES: Hemophilia A is characterized by a deficiency or absence of functional coagulation factor VIII resulting in uncontrolled or prolonged bleeding episodes. Bleeding can cause progressive joint damage with lasting effects, hence the need for prophylaxis therapy.

METHODS: We modeled the budget impact of adding antihemophilic factor (recombinant) Fc-VWF-XTEN fusion protein-ehtl to the formulary of a 1,000,000-member US private health plan (N=56 hemophilia A patients treated annually). Comparators included other factor VIII products: antihemophilic factor (recombinant), plasma/albumin-free method; antihemophilic factor, recombinant, PEGylated; and antihemophilic factor (recombinant), Fc fusion protein. We included drug acquisition costs attributable to prophylaxis and breakthrough bleeds (all assumed to be moderate severity). Antihemophilic factor (recombinant) Fc-VWF-XTEN fusion protein-ehtl dosing was based on the product label, and on real-world evidence for the comparators in the base case. Breakthrough bleeding rates during prophylaxis were based on pivotal trials. Market shares were applied to estimate the number of patients treated with each regimen over 5 years. Annual budget impact and incremental cost per patient per year (PPPY) were assessed and are reported in 2022 US dollars.

RESULTS: The addition of antihemophilic factor (recombinant) Fc-VWF-XTEN fusion protein-ehtl to a formulary was associated with a cumulative budget impact of $7.5 million over 5 years. Incremental cost PPPY ranged from $12,919 in Year 1 to $34,105 in Year 5 in the base case. A 37% discount to antihemophilic factor (recombinant) Fc-VWF-XTEN fusion protein-ehtl acquisition cost was required to generate a neutral budget impact.

CONCLUSIONS: Adding antihemophilic factor (recombinant) Fc-VWF-XTEN fusion protein-ehtl to a formulary to treat hemophilia A is associated with substantial budget impact to a US health plan. Model limitations include lacking consideration of individualized dosing, an assumption that breakthrough bleeding rates were the same regardless of patient characteristics, and exclusion of costs not related to drug acquisition.