Preferences and health utilities related to disease and treatment features for patients with hemophilia A in Canada

Background: Hemophilia A is caused by a mutation of clotting factor genes resulting in a deficiency of factor VIII (FVIII). Current treatments for hemophilia A in Canada include on-demand treatment as bleeds occur and regular intravenous prophylactic FVIII infusions. The subcutaneous therapy emicizumab was recently approved for the treatment of hemophilia A. The objective of this study was to estimate utility values associated with hemophilia A health and treatment states from a Canadian societal perspective, including preferences related to treatment efficacy as well as frequency and route of administration.Methods: A vignette-based time trade-off (TTO) utilities elicitation was undertaken to compare population preferences for 6 hemophilia health states describing prophylactic and on-demand treatment, with varying bleed rates and frequency of treatment administration. Health state definitions were informed by clinical experience, HAVEN3 results regarding bleed frequency, and supplemented with qualitative interviews of hemophilia patients and caregivers (n=10). Results: TTO interviews were conducted with 82 general population respondents. Mean utilities [95% CI] were highest for subcutaneous prophylaxis (0.90 [0.87-0.93]), followed by intravenous prophylaxis (0.81 [0.78-0.85]), with on-demand having the lowest utility (0.70 [0.65-0.76]). In regression analysis, subcutaneous treatment health states were associated with a utility increment of +0.1112. Additional bleeds and more frequent infusions were associated with lower utility values (-0.0027 per bleed and -0.0003 per infusion, respectively). Conclusion: Subcutaneous prophylaxis is associated with higher utility values compared to intravenous prophylactic and on-demand treatment, while increased bleeds and infusions are associated with reduced utility.