Long-Term Prophylaxis In Children, Adolescents and Young Adults with Von Willebrand Disease – First Results of a Cohort Study

Abstract 714

In children and young adults with von Willebrand disease [vWD] replacement therapy with von Willebrand factor (vWF)/factor VIII concentrates is increasingly performed as “prophylactic” therapy. Between 2000 and 2008, 82 consecutively enrolled children, adolescents and young adults with clinically meaningful bleeding episodes [spontaneous, peri- or postoperative] were diagnosed with vWD [type 1: 42/82; type 2: 24/82; type 3: 13/82; acquired: 3/82]. Here we report results of prophylaxic VWF replacement therapy in 32 patients [female: n=15; >Tanner 2: 9/15] with VWD type 1 [n=4], 2 [n=15] and 3 [n=13] in which a prophylactic treatment regimen was performed. Decision on prophylaxis was based on i) a pre-diagnostic bleeding score, and ii) on recurrent bleeds associated with microcytic anemia after diagnosis in patients with on-demand VWD therapy. Patients were treated with Humate P® (n=8; once switched to Wilfact®) or Wilate® (n=24). Median [min-max] dose was 40 (20-47) IU/kg, 23 patients were substituted twice weekly, 7 were treated three times, and two children 4 times per week. Within a six-months-period hemoglobin concentrations returned to normal values. Median [min-max] duration of prophylaxis was 3 years [1.0-9.0]. Recurrent bleeding episodes stopped in 31/32 patients, inhibitor development occurred in one. Following a 12-months observation period the bleeding frequency/bleeding score was significantly reduced, compared to pre-prophylaxis/pre-diagnostic values. The use of prophylactic VWF replacement therapy is an effective and well tolerated treatment modality, highly beneficial for children and young adults with vWD with recurrent bleeding events on on-demand therapy.