|View printer-friendly version|
Portola Pharmaceuticals Announces Second Part of Phase 3 ANNEXA(TM)-R Study: Andexanet Alfa and Rivaroxaban Meets Primary and Secondary Endpoints
"These positive topline data from Part 2 of the ANNEXA-R study mark the successful completion of our Phase 3 clinical program for andexanet alfa. We believe that the findings support the potential of andexanet alfa to become the first approved universal reversal agent for Factor Xa inhibitors and a standard of care to manage major bleeding associated with these novel anticoagulants," said
The ANNEXA-R study evaluated the safety and efficacy of andexanet alfa in reversing the anticoagulant effect of the Factor Xa inhibitor rivaroxaban, as measured by anti-Factor Xa activity, in older healthy volunteers. Part 1 of the study demonstrated rapid reversal with a bolus infusion, and Part 2 of the study now shows the ability of andexanet alfa to sustain that reversal. Topline data from Part 2 show that andexanet alfa, which was administered as an intravenous (IV) bolus followed by a continuous two-hour infusion, produced rapid reversal of the anticoagulant effect of rivaroxaban and sustained it for the duration of the infusion. In the study, andexanet alfa was well tolerated, with no serious adverse events, thrombotic events, or antibodies to Factor X or Xa reported.
"Just as with the ANNEXA-A study with apixaban, we now have clinical evidence that andexanet alfa can rapidly and significantly reverse the anticoagulant effect of rivaroxaban when administered as a bolus only or a bolus plus continuous infusion," continued Dr. Curnutte. "This means that andexanet alfa has the potential to treat patients who may need only short-duration reversal of their Factor Xa inhibitor anticoagulant as well as those who might require longer-duration reversal, such as those experiencing a severe intracranial hemorrhage or requiring emergency surgery."
About the ANNEXA-R Study
The randomized, double-blind, placebo-controlled Phase 3 ANNEXA-R study evaluated the safety and efficacy of andexanet alfa in reversing rivaroxaban-induced anticoagulation in healthy volunteers ages 50-68 years. Efficacy was evaluated using biomarker endpoints, with anti-Factor Xa levels as the primary endpoint. Secondary endpoints included plasma levels of free unbound rivaroxaban and endogenous thrombin potential (ETP), a measure of thrombin generation.
In Part 1, 41 healthy volunteers were given rivaroxaban 20 mg once daily for four days to steady state. They were then randomized in a 2:1 ratio to receive either andexanet alfa administered as an 800 mg IV bolus (n=27) or placebo (n=14).
Full results of Part 1 were presented at the
In Part 2, 39 healthy volunteers were given rivaroxaban 20 mg once daily for four days and were then randomized in a 2:1 ratio to receive either andexanet alfa administered as an 800 mg IV bolus followed by a continuous infusion of 8 mg/min for 120 minutes (n=26) or placebo (n=13). Part 2 of ANNEXA-R met all the primary and secondary endpoints with high statistical significance.
Full data from Part 2 of the ANNEXA–R study have been accepted for presentation during a Late Breaking Clinical Trial session at the
Statements contained in this press release regarding matters that are not historical facts are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements regarding: andexanet alfa's potential to treat patients needing reversal of Factor Xa anticoagulation effects, Portola's plans for pursuit of regulatory approval of andexanet alfa, and the likelihood of clinical, regulatory and commercial success for andexanet alfa and Portola's other product candidates. Risks that contribute to the uncertain nature of the forward-looking statements include: the accuracy of Portola's estimates regarding its ability to initiate and/or complete its clinical trials; the success of Portola's clinical trials and the demonstrated efficacy of Portola's product candidates to the satisfaction of regulatory authorities; the accuracy of Portola's estimates regarding its expenses and capital requirements; Portola's ability to manufacture andexanet alfa; regulatory developments in
CONTACT: Investor Contact:
Michele Mantynen Portola Pharmaceuticalsir@portola.com Media Contact: Julie Normart W2O Groupjnormart@w2ogroup.com