Twenty-five years' experience of prophylactic treatment in severe haemophilia A and B.

In Sweden, prophylactic treatment of boys with severe haemophilia has been practised since 1958 in an attempt to convert the disease from a severe to a milder form. The present study population consisted of 60 severe haemophiliacs (52 A, 8 B), aged 3-32 years. Treatment is started when the boys are 1-2 years of age, the regimens used being 24-40 IU F VIII kg-1 three times weekly in haemophilia-A cases (i.e. greater than 2000 IU kg-1 annually) and 25-40 IU F IX kg-1 twice weekly in haemophilia-B cases. The orthopaedic and radiological joint scores (maximum scores of 90 and 78, respectively) are evaluated as recommended by the World Federation of Haemophilia. Of those subjects aged 3-17 years, 29 out of 35 individuals had joint scores of zero. The oldest group had only minor joint defects. The VIII:C and IX:C concentrations had usually not fallen below 1% of normal. All 60 patients are able to lead normal lives. In conclusion, it appears to be possible to prevent haemophilic arthropathy by giving effective continuous prophylaxis from an early age, and preventing the VIII:C or IX:C concentration from falling below 1% of normal.