PB1177 - Preliminary performance data of an Anti-Xa Assay for the Quantitative Determination of Edoxaban

Background: For prevention from stroke in nonvalvular atrial fibrillation and for therapy in venous thromboembolism, patients require therapeutic anticoagulation with either vitamin K antagonists, or direct oral anticoagulants (DOACs). Although laboratory monitoring of DOACs is not required according to manufacturers, in specific clinical situations and for particular patient populations, testing may be helpful for patient management. For the quantitative determination of Xa-directed DOACs (i.e., rivaroxaban, apixaban, edoxaban) chromogenic anti-Xa assays originally developed for the quantitative determination of heparins, are proven valuable tools. In combination with drug specific calibrators, they allow quantification over a wide concentration range.

Aims: The INNOVANCE® Anti-Xa assay in combination with drug specific standards and controls is used for the quantitative determination of heparins, rivaroxaban and apixaban in human citrated plasma. Respective applications for automated analyzers are based on a chromogenic assay principle. For the quantitative determination of edoxaban, new applications employing edoxaban containing standards and controls are under development.
Aim of the studies was to assess the performance of these new edoxaban applications.

Methods: Studies were performed on the Sysmex® CS-2500 System, the Sysmex CN-3000/6000 Systems and the Atellica® COAG 360 System. Following studies were conducted: linearity, limit of quantitation (LoQ), precision, dilution recovery, and method comparison.

Results: Based on first results from linearity-, LoQ-, and precision-studies, the analytical measuring interval for all analyzer applications was defined to be 20–350 ng/mL. An extended measuring interval (1:2 sample dilution) of 350–700 ng/mL for all applications was demonstrated by dilution-recovery studies. Method comparison studies revealed good comparability to STA-Liquid Anti-Xa assay on the STA Compact Max system.

Conclusion(s): Applications for the Sysmex CS-2500 System, the Sysmex CN-3000/6000 Systems and the Atellica COAG 360 System using the INNOVANCE Anti-Xa assay in combination with edoxaban standards and controls demonstrate good performance regarding the quantitative determination of edoxaban in human citrated plasma.