REDUCED COAGULATION ACTIVATION FOLLOWING INFUSION OF A HIGHLY PURIFIED FACTOR-IX CONCENTRATE COMPARED TO A PROTHROMBIN COMPLEX CONCENTRATE

We have looked for evidence of coagulation activation in six subjects with haemophilia B by performing a single-blind active control cross-o ver study comparing a recently developed factor IX concentrate with a conventional prothrombin complex concentrate (PCC). Samples were obtai ned before infusion and at 0.25, 0.5, 1, 2, 4, 6, 12, 24, 36 and 48 h for assay of factor IX, prothrombin time, fibrinopeptide A (FPA), prot hrombin fragment F1+2, D-dimer, thrombin-antithrombin complexes (TAT) and antithrombin III (ATIII). Following administration of the PCC ther e was evidence of coagulation activation in five of the six recipients for up to 6 h after the infusion. The factor IX concentrate induced a moderate degree of coagulation activation in one subject. There was n o significant difference between the two products in respect of either recovery or half-life. This study provides further evidence that the new high purity preparations of factor IX concentrates produce signifi cantly less coagulation activation than currently available PCCs. It r emains to be established whether this will result in a corresponding r eduction in thromboembolic complications in clinical use.