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Measuring FVIII activity of glycopegylated recombinant factor VIII, N8-GP, with commercially available one-stage clotting and chromogenic assay kits : A two-centre study

Hillarp, A. LU ; Bowyer, A. E.; Ezban, M; Persson, P. and Kitchen, S. (2017) In Haemophilia 23(3). p.458-465
Abstract

Introduction: Factor VIII activity (FVIII:C) assays of samples containing glycoPEGylated recombinant FVIII such as turoctocog alfa pegol (N8-GP) can be associated with differences in FVIII recovery in vitro between various one-stage activated partial thromboplastin time (APTT)-based clotting assays and some chromogenic assays. Careful validation and qualification of specific assays and conditions is therefore necessary for the assessment of FVIII:C in samples containing modified FVIII molecules. Aim: To assess the ability of various one-stage clotting and chromogenic FVIII:C assays to measure samples containing N8-GP compared to unmodified recombinant FVIII (rFVIII) across two laboratory sites. Methods: Factor VIII activity in severe... (More)

Introduction: Factor VIII activity (FVIII:C) assays of samples containing glycoPEGylated recombinant FVIII such as turoctocog alfa pegol (N8-GP) can be associated with differences in FVIII recovery in vitro between various one-stage activated partial thromboplastin time (APTT)-based clotting assays and some chromogenic assays. Careful validation and qualification of specific assays and conditions is therefore necessary for the assessment of FVIII:C in samples containing modified FVIII molecules. Aim: To assess the ability of various one-stage clotting and chromogenic FVIII:C assays to measure samples containing N8-GP compared to unmodified recombinant FVIII (rFVIII) across two laboratory sites. Methods: Factor VIII activity in severe haemophilia A (HA) plasma spiked with a range of concentrations (from low, 0.20 IU mL-1, to high, 0.90 IU mL-1) of N8-GP and rFVIII, was determined at two laboratory sites using 12 commercially available one-stage clotting and chromogenic FVIII:C assays. Assays were performed using a plasma calibrator and different analysers. Results: Acceptable N8-GP recovery was observed in the low to high concentration samples tested using the majority of the tested APTT reagents with only one reagent causing a significant underestimation as compared to rFVIII. For the chromogenic assays, a slight overestimation was observed with some of the kits. Variability between the two laboratory sites are likely attributable to the use of different analysers with the respective APTT reagents. Conclusions: These results highlight the need to investigate the performance of modified factor products using standard assays. The performance of different one-stage clotting assays, APTT reagents, reference calibrators and instrumentation should also be evaluated.

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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Chromogenic FVIII assay, N8-GP, One-stage FVIII assay, Polyethylene glycol, Turoctocog alfa, Turoctocog alfa pegol
in
Haemophilia
volume
23
issue
3
pages
458 - 465
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • scopus:85013149291
ISSN
1351-8216
DOI
10.1111/hae.13168
language
English
LU publication?
no
id
e9c3aec7-6f62-44ec-b5d6-922d48e16ed0
date added to LUP
2017-03-02 10:11:34
date last changed
2018-01-07 11:53:31
@article{e9c3aec7-6f62-44ec-b5d6-922d48e16ed0,
  abstract     = {<p>Introduction: Factor VIII activity (FVIII:C) assays of samples containing glycoPEGylated recombinant FVIII such as turoctocog alfa pegol (N8-GP) can be associated with differences in FVIII recovery in vitro between various one-stage activated partial thromboplastin time (APTT)-based clotting assays and some chromogenic assays. Careful validation and qualification of specific assays and conditions is therefore necessary for the assessment of FVIII:C in samples containing modified FVIII molecules. Aim: To assess the ability of various one-stage clotting and chromogenic FVIII:C assays to measure samples containing N8-GP compared to unmodified recombinant FVIII (rFVIII) across two laboratory sites. Methods: Factor VIII activity in severe haemophilia A (HA) plasma spiked with a range of concentrations (from low, 0.20 IU mL<sup>-1</sup>, to high, 0.90 IU mL<sup>-1</sup>) of N8-GP and rFVIII, was determined at two laboratory sites using 12 commercially available one-stage clotting and chromogenic FVIII:C assays. Assays were performed using a plasma calibrator and different analysers. Results: Acceptable N8-GP recovery was observed in the low to high concentration samples tested using the majority of the tested APTT reagents with only one reagent causing a significant underestimation as compared to rFVIII. For the chromogenic assays, a slight overestimation was observed with some of the kits. Variability between the two laboratory sites are likely attributable to the use of different analysers with the respective APTT reagents. Conclusions: These results highlight the need to investigate the performance of modified factor products using standard assays. The performance of different one-stage clotting assays, APTT reagents, reference calibrators and instrumentation should also be evaluated.</p>},
  author       = {Hillarp, A. and Bowyer, A. E. and Ezban, M and Persson, P. and Kitchen, S.},
  issn         = {1351-8216},
  keyword      = {Chromogenic FVIII assay,N8-GP,One-stage FVIII assay,Polyethylene glycol,Turoctocog alfa,Turoctocog alfa pegol},
  language     = {eng},
  number       = {3},
  pages        = {458--465},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {Haemophilia},
  title        = {Measuring FVIII activity of glycopegylated recombinant factor VIII, N8-GP, with commercially available one-stage clotting and chromogenic assay kits : A two-centre study},
  url          = {http://dx.doi.org/10.1111/hae.13168},
  volume       = {23},
  year         = {2017},
}