Pharmacokinetic study of a high-purity factor IX concentrate (Factor IX Grifols®) with a 6-month follow up in previously treated patients with severe haemophilia B

Optimal replacement treatment in haemophilia B patients requires a good understanding of the pharmacokinetics of factor IX (FIX). The aim of this study was to compare the pharmacokinetic profile of Factor IX Grifols (R), a highly purified human FIX concentrate with two specific pathogen inactivation/removal steps, to that of available FIX preparations. The study was an open, non-randomized trial including 25 male subjects older than 12 years of age with severe haemophilia B. Pharmacokinetic profile of the FIX preparation regularly used by the subjects was determined as control. Pharmacokinetic profile of Factor IX Grifols (R) was determined twice, one 7-15 days after control assessment and second after a 6 months period had elapsed. Results showed that all products had peak plasma levels of FIX:C within 30 min. Mean recovery was 1.3 +/- 0.3 IU dL-1 per IU kg-1 for Factor IX Grifols (R) and 1.0 +/- 0.3 IU dL-1 per IU kg-1 for control products (P < 0.001). The mean terminal half-life (t(1/2)) for Factor IX Grifols (R) was 26.7 h and 26.8 h for control product. Pharmacokinetic parameters after 6 months of treatment with Factor IX Grifols (R) did not statistically differ from the parameters obtained with the first infusion. There were no adverse events related to Factor IX Grifols (R) for the duration of the study. In conclusion, Factor IX Grifols (R) has adequated pharmacokinetic properties comparable to the control plasma-derived FIX and these parameters remain stable after 6 months of treatment. Factor IX Grifols (R) can be an effective and safe plasma-derived FIX concentrate for replacement therapy in haemophilia B patients.