Table 4.

Andexanet alfa (PRT064445) – a factor Xa inhibitor antidote undergoing FDA review

Andexanet at a glance
Mechanism of action	Recombinant and inactivated form of factor Xa
	Binds factor Xa inhibitors: apixaban, rivaroxaban, and edoxaban
Proposed dose	400 mg IV bolus ±2 hours infusion at 4 mg/min*
Time to effect	2 minutes: 94% decrease in anti fXa activity§
	Effects of bolus last 1–2 hours
Adverse effects	No known prothrombotic effect – tissue factor pathway inhibitor interaction deserves further investigation
Possible indications	Life-threatening hemorrhage
	Emergent surgery

Notes:

^*Dose currently being investigated in Phase III, part 2 trial;

^§data from Crowther et al.⁴⁴

Abbreviation: FDA, Food and Drug Administration; IV, intravenous.