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Semin Thromb Hemost 2002; 28(3): 257-264
DOI: 10.1055/s-2002-32659
Copyright © 2002 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.: +1(212) 584-4662

Assaying the Circulating Factor VIII Activity in Hemophilia A Patients Treated with Recombinant Factor VIII Products

Marianne Mikaelsson1 , Ulla Oswaldsson2
  • 1Kabio HB, Stockholm, Sweden
  • 2Biovitrum AB, Stockholm, Sweden
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Publication History

Publication Date:
04 July 2002 (online)

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ABSTRACT

Large discrepancies between factor VIII assay methods have been reported from pharmacokinetic studies of recombinant factor VIII concentrates. In the assay of postinfusion patient plasma samples, traditional activated partial thromboplastin time (aPTT)-based one-stage clotting methods usually give results that are 20 to 50% lower than those obtained by chromogenic substrate assays. Investigations into the cause of these discrepancies have shown that the choice of phospholipid in the one-stage assay is crucial. The use of platelets or liposomes resembling platelet factor 3 instead of traditional aPTT reagents results in an increase in the apparent one-stage activity and a fairly good correlation with the chromogenic results. These and other functional test results, antigen measurements as well as clinical data, support the view that the chromogenic assay most accurately reflects the therapeutic effect. In addition to the differences among assay methods, there is also a discrepancy between the World Health Organization (WHO) standards for concentrates and plasma. The use of product-specific standards, prepared by diluting the factor VIII concentrate into hemophilic plasma, when assaying postinfusion plasma samples seems to be a feasible approach to overcome the problems encountered in pharmacokinetic studies.

KEYWORDS

Hemophilia A - factor VIII - recombinant - assay - pharmacokinetics

REFERENCES

  • 1 Barrowcliffe T W. Standardisation and assay.  Semin Thromb Hemost . 1993;  19 73-79
    Thieme ConnectPubMedSearch in Google Scholar
  • 2 Barrowcliffe T W, Raut S, Hubbard A R. Discrepancies in potency assessment of recombinant FVIII concentrates.  Haemophilia . 1998;  4 634-640
    CrossrefPubMedSearch in Google Scholar
  • 3 Barrowcliffe T W. Recommendations for the assay of high-purity factor VIII concentrates.  Thromb Haemost . 1993;  70 876-877
    PubMedSearch in Google Scholar
  • 4 Morfini M, Lee M, Messori A. The design and analysis of half-life and recovery studies for factor VIII and factor IX.  Thromb Haemost . 1991;  66 384-386
    Thieme ConnectPubMedSearch in Google Scholar
  • 5 Lusher J M, Hillman-Wiseman C, Hurst D. In vivo recovery with products of very high purity-assay discrepancies.  Haemophilia . 1998;  4 641-645
    CrossrefPubMedSearch in Google Scholar
  • 6 Lee C A, Owens D, Bray G. Pharmacokinetics of recombinant factor VIII (Recombinate) using one-stage clotting and chromogenic factor VIII assay.  Thromb Haemost . 1999;  82 1644-1647
    PubMedSearch in Google Scholar
  • 7 Mikaelsson M, Oswaldsson U, Frank L. Comparison of activity and antigen measurements in a pharmacokinetic study of recombinant factor VIII SQ (Abst 131).  Haemophilia . 1998;  4 187
    PubMedSearch in Google Scholar
  • 8 Nilsson I M, Barrowcliffe T W, Schimpf K. Factor VIII concentrates and their clotting activity.  Scand J Hematol . 1984;  33(Suppl 41) 13-68
    PubMedSearch in Google Scholar
  • 9 Rosén S. Assay of factor VIII:C with chromogenic substrate.  Scand J Hematol . 1984;  33(Suppl 40) 139-145
    PubMedSearch in Google Scholar
  • 10 Carlebjörk G, Oswaldsson U, Rosén S. A simple and accurate microplate assay for determination of factor VIII activity.  Thromb Res . 1987;  47 5-14
    CrossrefPubMedSearch in Google Scholar
  • 11 Mikaelsson M, Oswaldsson U, Sandberg H. Influence of phospholipids on the assessment of factor VIII activity.  Haemophilia . 1998;  4 646-650
    CrossrefPubMedSearch in Google Scholar
  • 12 Mikaelsson M. Assay discrepancies in pharmacokinetic studies of recombinant factor VIII concentrates. Presented at the SSC/ISTH subcommittee meeting, Maastricht, The Netherlands; June 15, 2000
  • 13 Mikaelsson M, Oswaldsson U. One-stage factor VIII assays are affected by both type and amount of phospholipids (Abst 1805).  Thromb Haemost . 1999;  82(Suppl) 574
    PubMedSearch in Google Scholar
  • 14 Roberts H R, Monroe D M, Oliver J A. Newer concepts of blood coagulation.  Haemophilia . 1998;  4 331-334
    CrossrefPubMedSearch in Google Scholar
  • 15 Mann K G. Biochemistry and physiology of blood coagulation.  Thromb Haemost . 1999;  82 165-174
    PubMedSearch in Google Scholar
  • 16 Bajaj S P, Joist J H. New insights into how blood clots: implications for the use of aPTT and PT as coagulation screening tests and in monitoring of anticoagulant therapy.  Semin Thromb Hemost . 1999;  25 407-418
    PubMedSearch in Google Scholar
  • 17 Nordfang O, Valentin S, Beck T C, Hedner U. Inhibition of extrinsic pathway inhibitor shortens the coagulation time of normal plasma and of hemophilia plasma.  Thromb Haemost . 1991;  66 464-467
    PubMedSearch in Google Scholar
  • 18 Aaro A, Oswaldsson U, Mikaelsson M. Comparison of r-VIII SQ with other factor VIII concentrates in the dilute thromboplastin test (Abst 34).  Haemophilia . 1998;  4 163
    PubMedSearch in Google Scholar
  • 19 Berntorp E. Second generation, B-domain deleted recombinant factor VIII.  Thromb Haemost . 1997;  78 256-260
    PubMedSearch in Google Scholar
  • 20 Oswaldsson U, Frank L, Mikaelsson M. Comparison of normal plasma and product-specific standards in the assessment of post-injection factor VIII activity (Abst 1806).  Thromb Haemost . 1999;  (Suppl) 574
    PubMedSearch in Google Scholar