About Hemophilia A

Factor VIII Activity Levels Matter

Lower Factor VIII levels put patients at greater risk for bleeds^1,2

WFH Guidelines,^* along with a retrospective analysis,† have shown that at Factor VIII levels of 5% to <40% (mild hemophilia), patients are vulnerable to traumatic, joint, and surgical bleeds, including subclinical bleeds.^1,2

Higher Factor VIII levels are associated with the ability to perform activities with lower risk of a bleed^{1,3‑6*‡§ll}

^* Data from the 2020 WFH Guidelines for the Management of Hemophilia, 3rd edition.^1,7
† Data from a study including 63 patients with severe hemophilia A treated with prophylaxis for at least 180 days.^2
‡ Data from a 2021 systematic review of physical activity in people with hemophilia across multiple databases, extracted using a standardized template and reported using a narrative synthesis.^4
§ Data from an expert elicitation study using Sheffield Elicitation Framework methodology quantified with probability analysis.^5
ll Data from a Delphi consensus statement using structured expert opinion to define target factor levels for use in different clinical situations.^6 
¶ WFH Guidelines define the upper limit of mild hemophilia as 40% factor activity, and the WFH Introduction to Hemophilia defines the normal range as 50% to 150%, which indicates that 40% to 50% would be in between mild hemophilia and normal, here referred to as “near-normal” levels.^1,7 

Is it time for a higher level of protection?

Achieving higher Factor VIII levels has the potential to:

^* Data from a post-hoc analysis of the association of Factor VIII levels and AUC with annualized bleeding rate in 34 patients on pharmacokinetic-guided prophylaxis.^8
† Data from a 2021 review of prophylaxis in hemophilia with respect to pharmacokinetics, alongside other factors that contribute to clinical decision-making.^9
‡ Data from a retrospective analysis of effect of hemophilia type and factor level on joint bleeding and orthopedic procedures in 4771 males with nonsevere hemophilia A or B without inhibitors receiving on-demand factor replacement therapy over a 12-year period.^10
§ Data from a randomized, controlled trial of secondary/tertiary prophylaxis vs on-demand treatment in adult and adolescent patients with severe hemophilia A over 3 years.^11
ll Data from the 2020 WFH Guidelines for the Management of Hemophilia, 3rd edition.^1,7
¶ Data from a post-hoc analysis of patient-reported pain surveys and joint health examinations assessing the association of demographic and clinical characteristics with perceptions of pain and functional abilities in 240 adult patients with hemophilia A or B (with or without inhibitors) and a history of joint pain or bleeding.^12
# Data from a 2021 systematic review of physical activity in people with hemophilia across multiple databases, extracted using a standardized template and reported using a narrative synthesis.^4
** Data from an expert elicitation study using Sheffield Elicitation Framework methodology quantified with probability analysis.^5
†† Data from a study including 63 patients with severe hemophilia A treated with prophylaxis for at least 180 days.²

Improving bleed protection may allow closer-to-normal activity for patients with hemophilia A

Factor VIII levels and their impact on the ability to perform activities

^* WFH Guidelines define the upper limit of mild hemophilia as 40% factor activity, and the WFH Introduction to Hemophilia defines the normal range as 50% to 150%, which indicates that 40% to 50% would be in between mild hemophilia and normal, here referred to as “near-normal” levels.^1,14
† Factor levels should be assessed based on an individual patient basis.