The Nijmegen ultra-sensitive Bethesda Assay detects very low-titer factor VIII inhibitors in patients with congenital and acquired hemophilia A.
Acquired hemophilia A
Factor VIII
Hemophilia A
Inhibitor
Nijmegen Bethesda Assay
Non-neutralizing antibodies
Pharmacokinetic
Journal
Thrombosis research
ISSN: 1879-2472
Titre abrégé: Thromb Res
Pays: United States
ID NLM: 0326377
Informations de publication
Date de publication:
11 2023
11 2023
Historique:
received:
19
07
2023
revised:
23
09
2023
accepted:
04
10
2023
medline:
6
11
2023
pubmed:
17
10
2023
entrez:
16
10
2023
Statut:
ppublish
Résumé
An inhibitor can develop in congenital hemophilia A (HA) patients against exogenous infused factor (F)VIII, whereas in acquired HA (AHA) inhibitors initially develop against endogenous FVIII. Inhibitors can be detected with the Nijmegen Bethesda Assay (NBA), which has an international cut-off level of 0.60 Nijmegen Bethesda Units/mL (NBU/mL). Thereby, very low-titer inhibitors may remain undetected. To describe the design and validation of the Nijmegen ultra-sensitive Bethesda Assay (NusBA) for the detection of very low-titer inhibitors. The NusBA is a modification of the NBA in which the ratio of patient plasma to normal pooled plasma is changed from 1:1 to 9:1. Analytical validation was performed according to the CLSI EP10 guideline in order to determine trueness and reproducibility. Clinical validation was performed in two cohorts of congenital HA patients (82 adults) with pharmacokinetic data and four AHA patients. The limit of quantitation (LOQ) was determined by measuring plasma samples spiked with inhibitor levels in the low range (0.05-0.80 NBU/mL). The LOQ for the NusBA was 0.10 NusBU/mL, with a coefficient of variation of 24.2 %. Seven (8.5 %) congenital HA patients had a positive NusBA result, of which only one was detected with the NBA. There was no correlation between NusBA and FVIII half-life. In three of the AHA patients the NusBA remained positive, when the NBA became negative. The NusBA is able to detect very low-titer FVIII inhibitors of ≥0.10 NBU/mL. Thereby, it may have added value in early inhibitor detection and therapy adjustments in patients with congenital HA and AHA.
Sections du résumé
BACKGROUND
An inhibitor can develop in congenital hemophilia A (HA) patients against exogenous infused factor (F)VIII, whereas in acquired HA (AHA) inhibitors initially develop against endogenous FVIII. Inhibitors can be detected with the Nijmegen Bethesda Assay (NBA), which has an international cut-off level of 0.60 Nijmegen Bethesda Units/mL (NBU/mL). Thereby, very low-titer inhibitors may remain undetected.
AIM
To describe the design and validation of the Nijmegen ultra-sensitive Bethesda Assay (NusBA) for the detection of very low-titer inhibitors.
METHODS
The NusBA is a modification of the NBA in which the ratio of patient plasma to normal pooled plasma is changed from 1:1 to 9:1. Analytical validation was performed according to the CLSI EP10 guideline in order to determine trueness and reproducibility. Clinical validation was performed in two cohorts of congenital HA patients (82 adults) with pharmacokinetic data and four AHA patients. The limit of quantitation (LOQ) was determined by measuring plasma samples spiked with inhibitor levels in the low range (0.05-0.80 NBU/mL).
RESULTS
The LOQ for the NusBA was 0.10 NusBU/mL, with a coefficient of variation of 24.2 %. Seven (8.5 %) congenital HA patients had a positive NusBA result, of which only one was detected with the NBA. There was no correlation between NusBA and FVIII half-life. In three of the AHA patients the NusBA remained positive, when the NBA became negative.
DISCUSSION
The NusBA is able to detect very low-titer FVIII inhibitors of ≥0.10 NBU/mL. Thereby, it may have added value in early inhibitor detection and therapy adjustments in patients with congenital HA and AHA.
Identifiants
pubmed: 37844518
pii: S0049-3848(23)00284-0
doi: 10.1016/j.thromres.2023.10.007
pii:
doi:
Substances chimiques
Factor VIII
9001-27-8
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
112-120Informations de copyright
Copyright © 2023. Published by Elsevier Ltd.
Déclaration de conflit d'intérêts
Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: MV and DM received a research grant from Sobi. WvH received unrestricted grants from Bayer, Shire, Novo Nordisk and CSL Behring. WvH is the founder and CSO of Enzyre BV, a Radboudumc spinoff company. SS received a research grant from Bayer. JOD has served on the speaker's bureau for Baxter, Bayer, Novo Nordisk, Sobi, Boehringer Ingelheim, Leo Pharma, Takeda and Octapharma. He has also served on the advisory boards of Baxter, Sobi, Bayer, Octapharma CSL Behring, Daiichi Sankyo, Boehringer Ingelheim, Takeda and Pfizer. JOD has also received research grant funding awards from 3M, Baxter, Bayer, Pfizer, Shire, Takeda, 3M and Novo Nordisk. BR was a full-time employees of Baxalta Innovations GmbH at the time when the laboratory part of the study was conducted. PT is full-time employee of Baxalta Innovations GmbH, a member of the Takeda group of companies, and shareholder of Takeda Pharmaceutical Company Limited. LV, BS, RP, NB, JJ, HT, EE have no conflict of interests to declare.