Andexanet Alfa Can Reverse Effect of Factor Xa Inhibitors

(HealthDay News) — Andexanet alfa (andexanet) can reverse the anticoagulant effects of factor Xa inhibitors, according to a study published online Nov. 11 in the New England Journal of Medicine to coincide with the annual meeting of the American Heart Association, held from Nov. 7 to 11 in Orlando, Fla.

Deborah M. Siegal, M.D., from McMaster University in Hamilton, Canada, and colleagues gave healthy older volunteers apixaban or rivaroxaban daily. For each factor Xa inhibitor, they conducted a two-part randomized placebo-controlled study to examine andexanet administered as a bolus or bolus plus two-hour infusion.

The researchers found that among apixaban-treated participants, there was a 94 and 21 percent reduction in anti-factor Xa activity with andexanet bolus and placebo, respectively; unbound apixaban concentration was reduced by 9.3 and 1.9 ng/mL, respectively; and thrombin generation was fully restored in 100 and 11 percent of participants, respectively (all P < 0.001). Among rivaroxaban-treated participants, anti-factor Xa activity was reduced by 92 and 18 percent among those who received andexanet bolus and placebo, respectively; unbound rivaroxaban concentration was reduced by 23.4 and 4.2 ng/mL, respectively; and thrombin generation was fully restored in 96 and 7 percent, respectively (all P < 0.001).

“Andexanet reversed the anticoagulant activity of apixaban and rivaroxaban in older healthy participants within minutes after administration and for the duration of infusion, without evidence of clinical toxic effects,” the authors write.

The study was funded by pharmaceutical companies, including Portola Pharmaceuticals, the manufacturer of andexanet alfa.

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