Development of a Simple Chromogenic Factor VIII Assay for Clinical Use

Wagenvoord, Rob; Hendrix, H; Hemker, H.C.

doi:10.1159/000215917

Cited by 7 publications

(15 citation statements)

References 8 publications

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“…The K.m is 45 nM. The Km is comparable with that found in the case of factor VIII assay [24]. Although in that case the composition of the factor X activating complex was different, it was composed of bovine factor IXa and human factor VIIIa.…”

Section: Optimization O F the Factor IX Assaysupporting

confidence: 70%

“…The dependency of the assay on phospho lipid concentration and composition is very similar as described by Van Dieijen et al [7] and Wagenvoord et al [24]. For that reason only the results of these studies are given.…”

Section: Optimization O F the Factor IX Assaysupporting

confidence: 58%

“…a-NAPAP was added to the FXa substrate to inhibit hydrolysis of this chromogenic substrate by thrombin. 1 pM a-NAPAP inhibits thrombin by 99.5% [24],…”

Section: Proteinsmentioning

confidence: 97%

“…Factor VIII was measured as described by Wagenvoord et al [24], As reference plasma normal pooled citrated plasma was used that was prepared from 15 healthy donors; the plasma was donated by T. Janssen-Claessen. The reference plasma was compared a few times with the reference plasma provided by Baxter (CoagCal).…”

Section: Proteinsmentioning

confidence: 99%

“…In a similar way as described by Wagenvoord et al [24], the Km of factor X activa tion by the complete factor X activating complex was determined. The K.m is 45 nM.…”

Section: Optimization O F the Factor IX Assaymentioning

confidence: 99%

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Development of a Sensitive and Rapid Chromogenic Factor IX Assay for Clinical Use

Wagenvoord¹,

Hendrix²,

Tran

et al. 1990

Pathophysiol Haemos Thromb

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A chromogenic factor IX assay is developed which requires only two time-dependent steps. Diluted plasma is mixed with a reagent containing factors VIII and X. The reaction is started by addition of a reagent containing factor XI_a, thrombin, CaCl₂, and phospholipids. Then factor XI_a activates factor IX if present, thrombin activates factor VIII, and subsequently the complete factor X activating complex (factor IX_a, factor VIII_a, Ca ions, and phospholipids) rapidly activates factor X. Finally, ethylenediaminetetraacetic acid plus a chromogenic substrate are added to stop the reaction and to measure formed factor X_a. Factor X_a formation is proportional to the plasma factor IX concentration (from 0 to 140%). The two reagents needed for the assay are stable at room temperature during a whole working day and for 3 h at 37 °C. A new isolation procedure for factor VIII is described. Factor VIII is purified from bovine plasma in a few steps with a yield of 20% and a 8,000-fold purification.

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Section: Optimization O F the Factor IX Assaysupporting

confidence: 70%

Section: Optimization O F the Factor IX Assaysupporting

confidence: 58%

“…a-NAPAP was added to the FXa substrate to inhibit hydrolysis of this chromogenic substrate by thrombin. 1 pM a-NAPAP inhibits thrombin by 99.5% [24],…”

Section: Proteinsmentioning

confidence: 97%

Section: Proteinsmentioning

confidence: 99%

“…In a similar way as described by Wagenvoord et al [24], the Km of factor X activa tion by the complete factor X activating complex was determined. The K.m is 45 nM.…”

Section: Optimization O F the Factor IX Assaymentioning

confidence: 99%

See 3 more Smart Citations

Development of a Sensitive and Rapid Chromogenic Factor IX Assay for Clinical Use

Wagenvoord¹,

Hendrix²,

Tran

et al. 1990

Pathophysiol Haemos Thromb

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Shifting landscape of hemophilia therapy: Implications for current clinical laboratory coagulation assays

Al‐Samkari

Croteau

2018

American J Hematol

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Clinical coagulation assays are an integral part of diagnosing and managing patients with hemophilia; however, in this new era of bioengineered factor products and non-factor therapeutics, problems have arisen with use of traditional coagulation tests for the quantification of several of these new products. Discussion over the use of one-stage clotting assays versus chromogenic substrate assays for clinical decision making and potency labeling has been ongoing for many years. Emerging factor concentrates have heightened concern over assay selection and availability. Emicizumab interferes with all aPTT based assays, rendering them unreliable and potentially falsely reassuring to the unaware provider. This review explores considerations for coagulation assays in the clinical setting and highlights how awareness of institutional coagulation assays and potential limitations have never been more critical for providers caring for patients with bleeding disorders. This article is protected by copyright. All rights reserved.

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Evaluation of the Pharmacokinetics, Pharmacodynamics, and Safety of a Single Dose of Emicizumab in Healthy Chinese Subjects

Zhang

Petry

et al. 2020

Clinical Pharm in Drug Dev

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This phase 1, open‐label, single‐center study evaluated the pharmacokinetics (PK), pharmacodynamics, safety, and tolerability of single‐dose emicizumab in healthy Chinese males. Overall, 16 subjects received a single subcutaneous dose of 1‐mg/kg emicizumab. Blood samples were obtained before dosing on day 1 and at regular intervals over 16 weeks after dosing for PK evaluation. A single 1‐mg/kg subcutaneous dose of emicizumab was safe and well tolerated in healthy Chinese male subjects in the study. Mean (± standard deviation) area under the concentration‐time curve from time 0 to infinity and maximum concentration were 287 ± 74.2 μg⋅d/mL and 7.11 ± 1.77 μg/mL, respectively, with a terminal half‐life of 26.7 (±4.3) days. Emicizumab administration did not show significant impact on pharmacodynamic markers tested, which mostly remained stable throughout the study. One subject tested positive for antidrug antibody, with no impact on his PK or safety profile. Compared with results from healthy Japanese and Caucasian subjects receiving the same dose in previous clinical trials, the current results further indicated the absence of difference of emicizumab PK profile across Chinese, Japanese, and Caucasian subjects, validating the use of similar therapeutic doses in Asian and non‐Asian populations.

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Development of a Simple Chromogenic Factor VIII Assay for Clinical Use

Cited by 7 publications

References 8 publications

Development of a Sensitive and Rapid Chromogenic Factor IX Assay for Clinical Use

Development of a Sensitive and Rapid Chromogenic Factor IX Assay for Clinical Use

Shifting landscape of hemophilia therapy: Implications for current clinical laboratory coagulation assays

Evaluation of the Pharmacokinetics, Pharmacodynamics, and Safety of a Single Dose of Emicizumab in Healthy Chinese Subjects

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