FDA approves Andexxa as antidote for patients treated with rivaroxaban and apixaban.- Portola Pharma.

Portola Pharmaceuticals announced that the FDA has approved Andexxa [coagulation factor Xa (recombinant), inactivated-zhzo], the first and only antidote indicated for patients treated with rivaroxaban and apixaban, when reversal of anticoagulation is needed due to life-threatening or uncontrolled bleeding. Andexxa received both U.S. Orphan Drug and FDA Breakthrough Therapy designations and was approved under the FDA�s Accelerated Approval pathway based on the change from baseline in anti-Factor Xa activity in healthy volunteers. Continued approval for this indication may be contingent upon post-marketing study results to demonstrate an improvement in hemostasis in patients.

The approval of Andexxa is supported by data from two Phase III ANNEXA studies (ANNEXA-R and ANNEXA-A) published in The New England Journal of Medicine, which evaluated the safety and efficacy of Andexxa in reversing the anticoagulant activity of the Factor Xa inhibitors rivaroxaban and apixaban in healthy volunteers. Results demonstrated that Andexxa rapidly and significantly reversed anti-Factor Xa activity (the anticoagulant mechanism of these medicines). The median decrease in anti-Factor Xa activity from baseline was 97 percent for rivaroxaban and 92 percent for apixaban.

Interim data from the ongoing ANNEXA-4 single-arm, open-label study in patients with major bleeding also were assessed by the FDA as part of its review and approval. Data from 185 evaluable patients showed that Andexxa rapidly and significantly reversed anti-Factor Xa activity when administered as a bolus and sustained this reversal when followed by a 120-minute infusion. The median decrease from baseline was 90 percent for rivaroxaban and 93 percent for apixaban.

The post-marketing requirement is a clinical trial that randomizes patients to receive either Andexxa or usual care (the type of care the enrolling institution would provide in the absence of Andexxa). This study is scheduled to be initiated in 2019 and be reported in 2023. Portola expects to launch Andexxa under an Early Supply Program with Generation 1 product in early June. Broader commercial launch is anticipated in early 2019 upon FDA approval of its Generation 2 manufacturing process.

Comment: The Marketing Authorization Application (MAA) for andexanet alfa is also under review by the European Medicines Agency. The Committee for Medicinal Products for Human Use (CHMP) communicated a positive trend vote on the MAA in February 2018. A formal opinion from the CHMP is expected by the end of 2018, and the European Commission is expected to issue a decision in early 2019.