DDAVP (desmopressin; 1-deamino-cys-8-D-arginine-vasopressin) treatment in children with haemophilia B

We tested the response to desmopressin (1-deamino-cys-8-D-arginine-vasopres sin: DDAVP) in four patients with haemophilia B [factor IX (F IX) at diagno sis 1.4-5%]. The activated partial thromboplastin time (aPTT) was significa ntly shortened in all patients. Although there was an up to 1.4-fold increa se in F IX levels in three patients, maximal F TX activity remained below 1 0%. Much more prominent were the increases in F VIII (three- to fourfold), in von Willebrand factor antigen (VWF:Ag; 2.5-fold) and particularly in VWF collagen-binding activity (VWF:CBA; fivefold). These changes were reflecte d by the prophylactic efficacy of DDAVP for dental surgery. After pretestin g, DDAVP could be a useful drug for reducing the need for plasma products f or prevention of minor surgical bleeding in patients with mild to moderate haemophilia B.