Among individuals with haemophilia, the inherited X-linked disorder caused by deficient factor VIII or factor IX and characterised by spontaneous and traumatic bleeding in joints and the body cavity, the major goal of treatment is prevention of bleeding or prophylaxis. Prophylaxis with factor concentrate is known to reduce the number of bleeds and improve joint health, mobility, and quality of life, 1 Manco-Johnson MJ Abshire TC Shapiro AD et al. Prophylaxis versus episodic treatment to prevent joint disease in boys with severe hemophilia.

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and pharmacokinetic studies have found that, although increasing the time above factor levels of 1% substantially reduces bleeds, 2 Collins PW Blanchette VS Fischer K et al. Break-through bleeding in relation to predicted factor VIII levels in patients receiving prophylactic treatment for severe hemophilia A.

J Thromb Haemost. 2009; 7: 413-420

maintaining levels of 15% eliminates bleeds. 3 den Uijl IE Fischer K Van Der Bom JG Grobbee DE Rosendaal FR Plug I Analysis of low frequency bleeding data: the association of joint bleeds according to baseline FVIII activity levels.

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Because compliance is the best determinant of factor VIII and bleeding, 2 Collins PW Blanchette VS Fischer K et al. Break-through bleeding in relation to predicted factor VIII levels in patients receiving prophylactic treatment for severe hemophilia A.

J Thromb Haemost. 2009; 7: 413-420

efforts to reduce dose frequency by improving half-life led to the development of extended half-life factor concentrate by Fc-fusion, albumin fusion, and pegylation technologies.