*Healthy Patient Studies

July 15, 2013

Portola Pharmaceuticals reported results from a phase II proof-of-concept study of its investigational Factor Xa inhibitor antidote PRT4445 in healthy volunteers who were administered the Factor Xa inhibitor Eliquis. The randomized, placebo-controlled, double-blind, cohort dose-escalation study enrolled 27 healthy volunteers who were treated on days one through six with Eliquis 5mg twice daily and then randomized in a 6:3 ratio to intravenous PRT4445 (in three different dose cohorts—90mg, 210mg or 420mg) or saline on day six, three hours after receiving the last Eliquis dose. Two minutes after administration of 420mg PRT4445 (n=6), the anticoagulant activity of Eliquis decreased by > 95% as measured by anti-Factor Xa activity. The 210mg dose reduced anti-Factor Xa activity by 80% compared with saline (n=9). The reversal of anti-Factor Xa activity correlated with a reduction in the level of free, unbound Eliquis in the plasma consistent with the mechanism of action of PRT4445. In the study, PRT4445 was well-tolerated, with no serious effects observed.

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