Abstract Number: PB0218
Meeting: ISTH 2022 Congress
Background: Mim8 is a new bispecific antibody that mimics the cofactor function of activated factor VIII (FVIIIa) by bridging activated factor IX (FIXa) and factor X, and enhancing the proteolytic function of FIXa to activate FX. It is currently in phase 3 clinical development for prophylaxis in patients with haemophilia A (HA), independent of inhibitor status.
Measurement of the drug concentration in a plasma sample may be useful to follow up Mim8 therapy.
Aims: Evaluate the use of Stago modified one stage assay (OSA) and chromogenic substrate assay (CSA) to determine plasma levels of Mim8.
Methods: A severe haemophilia A plasma was spiked with Mim8 at concentrations ranging from 0 to 30 µg/mL. The concentration of Mim8 samples is determined with modified FVIII:C OSA using STA-PTT Automate / STA-Deficient FVIII or STA-CK Prest / STA-ImmunoDef FVIII and a modified FVIII:C CSA using TriniCHROM Factor VIII:C (all reagents Stago, Asnières sur Seine, France) on a STAR Max analyzer (Stago). Mim8 reference material from Novo Nordisk A/S (Malov, Denmark) was used as calibrator.
Results: Recovery of measured Mim8 concentration compared to the expected target concentration is similar for the different reagents tested with modified FVIII:C OSA and modified FVIII:C CSA, with a relative difference lower than 10% in most cases (12% for the lowest Mim8 concentration tested with STA-CK Prest and STA-ImmunoDef VIII) (table 1 and figure 1).
Conclusion(s): Modified method using either aPTT or chromogenic reagents from Stago can be used to quantify Mim8 concentration in a hemophiliac plasma sample using Mim8 reference material as calibrator.
To cite this abstract in AMA style:Martineau N, Fauconnier L, Roland N, Carlo A, Hervé T, Depasse F, Ezban M, Nicoud L. Adaptative methods using one-stage and chromogenic substrate assays for the quantitative measurement of Mim8 in human plasma [abstract]. https://abstracts.isth.org/abstract/adaptative-methods-using-one-stage-and-chromogenic-substrate-assays-for-the-quantitative-measurement-of-mim8-in-human-plasma/. Accessed November 30, 2023.
« Back to ISTH 2022 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/adaptative-methods-using-one-stage-and-chromogenic-substrate-assays-for-the-quantitative-measurement-of-mim8-in-human-plasma/