Quantification of emicizumab by mass spectrometry in plasma of people with hemophilia A: A method validation study

Anouk A.M.T. Donners*, László Gerencsér, Kim C.M. van der Elst, Toine C.G. Egberts, Moniek P.M. de Maat, Albert Huisman, Rolf T. Urbanus, Mohsin El Amrani

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

10 Citations (Scopus)
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Background: Emicizumab is a new treatment option for people with hemophilia A. Emicizumab was approved with a body-weight-based dosage regimen, without laboratory monitoring requirements. Guidelines, however, recommend measuring emicizumab concentrations when the presence of antidrug antibodies is suspected. Furthermore, drug monitoring can be useful in clinical decision making, in adherence checking, and for research purposes. Therefore, we developed a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for quantifying emicizumab. We performed a validation study on this LC-MS/MS method quantifying emicizumab in the plasma of people with hemophilia A. Methods: Sample preparation for LC-MS/MS analysis included ammonium sulfate protein precipitation and trypsin digestion. A signature peptide of emicizumab and a matching stable isotope-labeled internal standard were used to quantify emicizumab by LC-MS/MS analysis. Validation was performed in accordance with the “Guideline on Bioanalytical Method Validation” of the European Medicines Agency (EMA). The LC-MS/MS method was cross validated against a modified and calibrated (r2 Diagnostics) one-stage clotting assay (OSA). Conclusions: The LC-MS/MS method demonstrated linearity over a wide range of emicizumab concentrations, far exceeding the concentrations observed in people with hemophilia A. Precision and accuracy were excellent, and all other validation parameters were also within the acceptance EMA criteria. Cross validation showed that the LC-MS/MS method and the OSA-based method can be used interchangeably for drug monitoring of emicizumab without the application of a correction factor.

Original languageEnglish
Article numbere12725
JournalResearch and Practice in Thrombosis and Haemostasis
Issue number4
Publication statusPublished - Apr 2022

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© 2022 The Authors. Research and Practice in Thrombosis and Haemostasis published by Wiley Periodicals LLC on behalf of International Society on Thrombosis and Haemostasis (ISTH).


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