IndexXa is in development for patients treated with a Factor Xa inhibitor when reversal of anticoagulation is needed due to life-threatening or uncontrolled bleeding and for patients requiring urgent or emergency surgery.
Portola is seeking conditional approval of IndexXa in the EU through the centralized procedure. With the acceptance of the application, the EMA’s Committee for Medicinal Products for Human Use (CHMP) will now begin the centralized review procedure under a standard 210-day review period.
“An estimated 73,000 patients treated with an oral Factor Xa inhibitor will be hospitalized this year due to major bleeding or because they require urgent surgery in the EU5i. These patients are critically ill and could potentially benefit from a Factor Xa inhibitor antidote,” said Bill Lis, chief executive officer of Portola.
“As there is currently no approved antidote for Factor Xa inhibitors in the EU, we are working diligently to bring IndexXa to patients. The MAA validation is an important milestone toward achieving that goal.”
Portola’s MAA submission is based on data from two Phase 3 ANNEXA studies that evaluated the safety and efficacy of andexanet alfa in reversing the anticoagulant activity of the Factor Xa inhibitors rivaroxaban and apixaban in healthy volunteers. Results of the ANNEXA studies were published by The New England Journal of Medicine.
The MAA also included limited adjudicated efficacy and safety data from initial patients enrolled in the ongoing ANNEXA-4 study.
Portola is currently evaluating andexanet alfa in this global, Phase 3b/4 single-arm, open-label study in patients receiving apixaban, rivaroxaban, edoxaban or enoxaparin who present with an acute major bleed. The study is enrolling patients in the United States, Canada and the EU.
On August 17, 2016, Portola received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) regarding its Biologics License Application (BLA) for AndexXa. The Company plans to meet with the FDA as soon as possible in order to resolve the outstanding questions in the CRL and determine appropriate next steps.
The Urgent Need for a Factor Xa Inhibitor Antidote
Annually, 1 to 4 percent of patients treated with Factor Xa inhibitors may experience major bleeding, and an additional one percent may require emergency surgery. Commensurate with the increase in the use of Factor Xa inhibitors — for stroke prevention in atrial fibrillation; treatment and prevention of deep vein thrombosis (DVT) and pulmonary embolism; and prevention of DVT following knee or hip replacement surgery — the number of hospital admissions due to bleeding associated with these agents continues to grow. In the EU5 an estimated 73,000 oral Factor Xa inhibitor-treated patients will be hospitalized this year due to major bleeding or will require urgent surgery.ii
About IndexXa
IndexXa, an investigational drug, is a modified human Factor Xa molecule that acts as a decoy to target and sequester with high specificity both oral and injectable Factor Xa inhibitors in the blood.
Once bound, the Factor Xa inhibitors are unable to bind to and inhibit native Factor Xa, thus potentially allowing for the restoration of normal hemostatic processes. IndexXa is the first compound being studied as an antidote for Factor Xa inhibitors that directly and specifically reverses anti-Factor Xa activity – the anticoagulant mechanism of these agents.