PB0010 - Monitoring Direct Oral Anti Coagulants (DOAC) reversal agents in a chemiluminescent thrombin generation assay.

Background: Bleeding remains a clinical concern for patients at risk for thrombosis treated with traditional and direct oral anticoagulants (DOACs). In general, DOACs do not need any monitoring, but the following patient groups may experience an unmet medical need for DOAC therapy monitoring: acute trauma, advanced age, severe kidney disease, or other chronic medical conditions We analyzed with our chemiluminescence-based thrombin generation assay (TGAlum) whether reversal agents Idaricizumab and Andexanet Alfa were able to curtail clinical DOAC concentrations. This assay is intended to be implemented in a point of care use handheld system for anticoagulant DOAC therapy monitoring.

Aims: Evaluate the ability for our TGAlum to monitor reversal agents for DOAC therapy.

Methods: The chemiluminescence-based thrombin generation assay was performed in in 60 µL volume, using 40 µl 0.32% citrated plasma, and 20 µL buffer containing calcium, 1.0 pM Tissue Factor, phospholipids, a thrombin-specific aminoluciferin substrate and luciferase. 700 ng/mL Apixaban, Edoxaban and Dabigatran spiked in normal pooled plasma were titrated with 1-80 µg/mL Andaxenet Alfa (AA) and 15- 125 µg/ml Idaricizumab, respectively.

Results: Both DOACs reversal agents significantly curtailed the reduction of the thrombin generation assay. 60 µg/ml Idaricizumab cancelled the effect of 700 ng/mL Dabigatran. 10 µg/mL AA completely reversed 700 ng/mL Apixaban whereas 80 µg/mL AA was required for reversing the same concentration of Edoxaban. Moreover, AA shortened the lag-time from 3 min to 1 min, thereby indicating that the TGAlum is also sensitive towards inhibiting TFPI (Tissue Factor Pathway Inhibitor) function.

Conclusion(s): Our TGAlum thrombin generation assay may be a versatile tool for monitoring of DOAC reversal therapy. Ongoing studies are aimed the assay to monitor DOAC levels in acute or home settings using a prototype device that enables nanoscale-volume chemiluminescent thrombin generation assays.