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Related Experiment Videos

A multi-centre collaborative study on the potency estimation of ReFacto.

Anthony R Hubbard1, Dawn Sands, Eva Sandberg

  • 1Division of Haematology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, United Kingdom. thubbard@nibsc.ac.uk

Thrombosis and Haemostasis
|December 4, 2003
PubMed
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Estimating factor VIII (FVIII) activity using different standards yielded varied results. The ReFacto Laboratory Standard (RLS) provided more consistent estimates for recombinant FVIII concentrates compared to international standards.

Area of Science:

  • Biotechnology
  • Clinical Chemistry
  • Pharmacology

Background:

  • Accurate quantification of factor VIII (FVIII) coagulant activity is crucial for effective hemophilia treatment.
  • Chromogenic assays are widely used but can be influenced by the reference standard employed.
  • Recombinant FVIII concentrates (ReFacto) and plasma-derived FVIII (Octonativ-M) may exhibit differential responses in assays.

Purpose of the Study:

  • To compare the accuracy of factor VIII (FVIII) concentrate estimations using different reference standards.
  • To evaluate the performance of the ReFacto Laboratory Standard (RLS) against international standards (WHO 6th IS, EP#2).
  • To assess assay variability for recombinant and plasma-derived FVIII concentrates.

Main Methods:

  • Seven laboratories performed chromogenic assays to estimate FVIII coagulant activity.

Related Experiment Videos

  • Assays utilized recombinant (ReFacto) and plasma-derived (Octonativ-M) FVIII concentrates.
  • Estimations were made relative to three reference standards: WHO 6th IS, EP#2, and RLS.

    • Main Results:

    • Estimates for ReFacto were significantly higher when using the RLS compared to WHO 6th IS and EP#2.
    • ReFacto estimates using RLS were within 10% of labeled potency, while estimates using WHO 6th IS/EP#2 were 21-31% lower.
    • Octonativ-M estimates were within 10% of label using WHO 6th IS/EP#2, but 117% of label using RLS.

    Conclusions:

    • The ReFacto Laboratory Standard (RLS) offers more consistent estimates for recombinant FVIII concentrates.
    • Recombinant and plasma-derived FVIII may respond differently to assay methodologies and reference standards.
    • The initial assigned value of the RLS was likely too high, leading to adjusted unitage post-study.