Differential Effects of Dabigatran, Rivaroxaban, Apixaban, Edoxaban and Betrixaban on Fibrinokinetics and their Modulation by FEIBA
Authors: Venkitasubramony Vishnu , Hoppensteadt Debra , Jeske Walter , Siddiqui Fakiha , Fareed Jawed 
Published: June 2021

ObjectiveNew direct oral anticoagulants have a safety profile that differentiates them from traditionally used oral anticoagulants. DOACs with the similar mechanisms of action and structural similarities are being marketed by numerous companies under varied brands. Such widespread use warrants differentiation of these DOACs on clot formation and their neutralization profile by antidotes. Fibrinokinetics is a method in which thrombin induced clot formation can be measured. The purpose of this study is to compare the effect of Dabigatran, Rivaroxaban, Edoxaban, Betrixaban and Apixaban on thrombin induced fibrinokinetics in normal human plasma. Furthermore, the feasibility of factor eight inhibitor bypass agent (FEIBA) as an antidote to modulate these DOACs is investigated.Materials and MethodsCitrated pool blood plasma was obtained from Loyola blood bank. Purified thrombin was used as a trigger to generate clot at a concentration of 5U/ml. Powdered forms of Dabigatran, Rivaroxaban, and Apixaban were obtained commercially and were used at a working dilution of 1ug/mL. Fibrinokinetics was measured in microtiter plates using 175 microliter of plasma supplemented with the drugs to be tested at a concentration of 25uL of 5U of thrombin followed by 25uL of 0.025M of CaCl2. For the control well plates 25uL of saline was added. To study the FEIBA neutralization, 25uL of FEIBA at a concentration of 0.1U/mL was added in the other set of experimental well plates. The rate of clot formation was monitored for 30 minutes at A45 nm. Both kinetic and endpoint methods were used to calculate the rate of clot formation.ResultsIn the saline control system the time dependent increase in the clot formation was observed for a period of 30 minutes reaching the maximum of 1. Dabigatran, Edoxaban, Rivaroxaban produced a concentration dependent inhibition of clot formation whereas Apixaban and Betrixaban did not produce any significant inhibition of clot formation at concentration up to 1ug/mL. FEIBA supplementation at a final concentration 0.1U/mL produced an increase in clot density in the case of Betrixaban and Apixaban whereas FEIBA reversed the effect of Rivaroxaban, Edoxaban and Dabigatran at a lower concentration up to 0.125U/mL.ConclusionsThree groups can be stipulated from the results of this experiment. The first group includes Dabigatran and has the strongest effect on clot formation and experienced significant inhibition by FEIBA. The second group includes Rivaroxaban and Edoxaban with a strong factor Xa inhibitory activity and moderate neutralization by FEIBA. The third group includes Betrixaban and Apixaban with a weak factor Xa activity and insignificant modulation by FEIBA. The successful modulation by FEIBA on certain DOACs indicate that antidotes for these drugs in the future can stem from procoagulants that are already in use such as FEIBA.Support or Funding InformationNone.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.