1511 – Extended half-life (EHL) blood clotting factors VIII + IX

Health technology assessment

In Australia, recombinant clotting factors are currently used to treat haemophilia. In patients with severe haemophilia, the main form of treatment is prophylaxis with regular infusions of factor VIII or factor IX containing products. An alternative style of treatment is “on-demand”, administering clotting factors only after bleeds appear.

Prophylaxis for haemophilia A is usually given 2-3 times a week, or more frequently, due to the short half-life of the standard half-life FVIII products (10 – 14 hours). Plasma-derived or recombinant FIX products have a slightly longer half-life of around 15 to 20 hours. Prophylaxis for haemophilia B is therefore often approximately 40 IU/kg of FIX twice weekly.

A number of extended half-life (EHL) clotting factors have now been developed for the treatment of haemophilia A and B. Different strategies have been utilised to prolong the half-life with greater extension achieved for factor IX than factor VIII.

Type: Therapeutic

Haemophilia A and B are X-linked genetic diseases, caused by mutations affecting the coagulation protein factors VIII (Haemophilia A) and IX (Haemophilia B). Severe disease is defined as having <1% of FVIII or IX clotting activity. Moderate disease is between 1 and 5% of clotting activity, and mild haemophilia is having between 5 and 49% of clotting activity (Miguelino & Powell 2014). Patients with severe haemophilia are at risk of severe, life-threatening bleeding episodes, which may occur spontaneously (Miguelino & Powell 2014). Recurrent bleeds may cause severe arthropathy, soft-tissue haematomas, and retroperitoneal and intracerebral haemorrhages (Mancuso & Mannucci 2014). When patients are untreated, they have a short life expectancy of approximately 25 years (Miguelino & Powell 2014).

• PASC meeting: 7 - 8 December 2017
• ESC meeting: 8 June 2018
• MSAC meeting: 26 8 27 July 2018