Potency and mass of factor VIII in FVIII products
- 15 January 2009
- journal article
- Published by Wiley in Haemophilia
- Vol. 15 (1), 63-72
- https://doi.org/10.1111/j.1365-2516.2008.01826.x
Abstract
Summary. Several factor (F) VIII products of different origin and structure are being used for haemophilia A treatment worldwide. The assessment of FVIII concentration in these products is done using activity assays, which are dependent upon the assay and its modifications. To evaluate FVIII products for potency and for FVIII concentration and specific activity, three activity-based assays [activated partial thromboplastin time (APTT), intrinsic FXase and synthetic coagulation proteome] and two immunoassays (ELISA and western blotting) were used in this study with albumin-free full-length recombinant (r) FVIII as a standard. In all activity assays, products A and B (both contain full-length rFVIII) at 1 U mL−1 showed potency similar to that of the 0.7 nm (1 U mL−1) rFVIII standard. Product E (contains truncated rFVIII) was less potent in the APTT (83% of standard) and product C (contains plasma FVIII) was less potent in FXase assays (66%). The ELISA immunoassay revealed that the specific activity of FVIII proteins in products A–C and E varied over a wide range (3900–13 200 U mg−1) and was higher for most lots when compared with the standard (5000 U mg−1), whereas the specific activity of product D (contains plasma FVIII) was lower than expected (3200–4800 U mg−1). (i) FVIII potency estimated in different assays gives dissimilar results; (ii) the specific activity of FVIII in various FVIII products is different and inconsistent. Thus, the administration of an equal FVIII potency in units means the administration of different amounts of FVIII protein, which may partly explain apparent discrepancies in product performance.Keywords
This publication has 48 references indexed in Scilit:
- Hepatitis, Epidemiology and Liver Function in Hemophiliacs in SwedenActa Medica Scandinavica, 2009
- Intrinsic stability and functional properties of disulfide bond‐stabilized coagulation factor VIIIa variantsJournal of Thrombosis and Haemostasis, 2006
- Relationships between factor VIII:Ag and factor VIII in recombinant and plasma-derived factor VIII concentratesHaemophilia, 2004
- Coagulation and Chromogenic Assays of Factor VIII Activity: General Aspects, Standardization, and RecommendationsSeminars in Thrombosis and Hemostasis, 2002
- Assaying the Circulating Factor VIII Activity in Hemophilia A Patients Treated with Recombinant Factor VIII ProductsSeminars in Thrombosis and Hemostasis, 2002
- Measurement of factor VIII activity of B-domain deleted recombinant factor VIIISeminars in Hematology, 2001
- Effects of HIV infection on age and cause of death for persons with hemophilia A in the United StatesAmerican Journal of Hematology, 2001
- The size of human factor VIII heterodimers and the effects produced by thrombinBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1986
- A CONCENTRATE OF HUMAN ANTIHÆMOPHILIC FACTOR: ITS USE IN SIX CASES OF HÆMOPHILIAThe Lancet, 1957