Prophylaxis for severe haemophilia: clinical challenges in the absence as well as in the presence of inhibitors.

Prophylaxis is defined as the regular administration of clotting factor concentrates to prevent bleeding. Extensive data from observational studies and a recent randomized controlled trial (have established that early prophylactic treatment prevents bleeds and arthropathy in boys with severe haemophilia. The initiation of prophylaxis in young children remains challenging. To prevent arthropathy, prophylaxis should be started early, before the onset of joint damage. Alternative strategies of starting include starting before the age of 2 years, or starting before the third joint bleed. Dose and frequency vary between the original Swedish regime of 20-40 IU kg(-1) three times per week and lower dosed and step up regimes starting with 50 IU kg(-1) once weekly and rapidly increasing dose and frequency in case of bleeds. In the second decade, most patients on prophylaxis learn self-infusion. Self-management warrants confirmation of adequate knowledge of the disease. Increasing self-management concurring with major physical and psychological changes may cause reduced adherence. The challenge is to promote adherence and continue to prevent bleeds during this important period of rapid growth. The third decade of life often represents a change in lifestyle. Patients may get a job and periods of physical activity may be more confined. About two thirds of patients experiment with discontinuing prophylaxis in their early twenties, and 20-30% with mild bleeding patterns switch to on-demand treatment for prolonged periods or even permanently. The challenge is to optimize efficiency by individualizing prophylactic dose and frequency according to lifestyle and bleeding pattern. Inhibitors may develop in up to 30% of patients with severe haemophilia. Especially those with high titre inhibitors are at increased risk of developing target joints and severe arthropathy. The use of prophylactic treatment with bypassing agents in inhibitor patients is increasing. Early studies report in a significant reduction of bleeds, including intracranial bleeds, and improvement in quality of life. Data on results of primary prophylaxis in patients with inhibitors to prevent arthropathy are not yet available.