Results of secondary prophylaxis in children with severe hemophilia.

In this study, 13 children with severe hemophilia were given routine replacement infusions of factor VIII or IX to treat arthropathy. The children who had a mean age of 6.9 years (range 2.0-12.5) at initiation of prophylaxis had experienced an average of 43 acute hemorrhages (range 8-127) in the year prior to prophylaxis, of which a mean of 24 (range 5-46) were into joints. Therapy was begun in five children, using factor VIII concentrate at 20 U/kg three times a week, and one boy received factor IX concentrate 40 U/kg twice a week. This dose schedule was inadequate for three factor VIII-deficient boys and for the one factor IX-deficient boy. Two of three factor VIII-deficient boys responded to an increase to 30 U/kg prior to the 3-day interval. The dose frequency was increased to three times a week for the factor IX-deficient boy, but he continued to bleed and was taken to synovectomy. One of the original five factor VIII-deficient boys plus seven other factor VIII-deficient boys were begun on factor VIII 20 U/kg every other day; 3 boys ceased bleeding. Trough factor VIII levels were measured 24 hr after an infusion in the five boys who continued to bleed. Factor VIII dosage was adjusted to achieve a trough level of > 1%; 4 responded to an increase in the dose of factor VIII; 1 had an adequate trough but, due to compliance issues, was taken to synovectomy. Serial clinical and radiographic assessments determined stabilization of joint disease in more than one-half of the boys. No child showed reversal of abnormal radiographic findings. Institution of aggressive factor VIII and IX concentrate in children with established hemophilic arthropathy does not reverse joint disease but may alter the clinical course of hemophilia. Future studies to compare this intervention with primary prophylaxis instituted prior to the onset of recurrent joint hemorrhage are warranted.