Pharmacokinetic properties of two factor VIII concentrates with single and double viral inactivation

In order to assess whether addition of a modified pasteurization step to the manufacture of a solvent/detergent-treated factor VIII concentrate of high purity has affected its properties, three sets of pharmacokinetic studies were performed. In an open, controlled study with seven patients and a double-blind cross-over study with nine patients, the pharmacokinetic parameters of the double virus-inactivated preparation were compared with those of a mono-inactivated product, using a one-stage clotting assay. In a longitudinal study comparison was made between baseline and 8 months after treatment with the double virus-inactivated product in six patients, using three different factor VIII assays. There were no differences in recovery, clearance or half-life between the single- and double-inactivated products. After 8 months of treatment, the half-life and mean residence time were longer with the one-stage clotting assay, whereas the chromogenic assay showed a lower recovery, a faster cleareance and smaller area under the curve with the double virus-inactivated product. All differences were small and none was consistent in all three methods. In conclusion, the double virus inactivation does not appear to have affected the pharmacokinetic characteristics of this factor VIII preparation.