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FDA grants orphan drug status to Factor Xa inhibitor antidote
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The FDA has granted orphan drug designation to andexanet alfa for the treatment of patients with serious, uncontrolled bleeding events or who require emergency surgery, according to a press release from the drug’s manufacturer.
Andexanet alfa (Portola Pharmaceuticals) is a breakthrough-designated Factor Xa inhibitor antidote. The agent is designed to reverse the anticoagulant effects of direct or indirect Factor Xa inhibitors to restore normal hemostatic processes. Currently, there is no approved antidote for bleeding associated with Factor Xa inhibitors.
"Orphan drug designation for andexanet alfa recognizes its potential to address a significant unmet medical need and to advance the field by helping patients who currently have no treatment options. Four factor prothrombin complex concentrates (PCCs), which are indicated for warfarin reversal, have not demonstrated reversal of Factor Xa inhibitor activity and have a black box warning for fatal and nonfatal thromboembolic events," Bill Lis, CEO of Portola Pharmaceuticals, said in a press release.
Portola is evaluating andexanet alfa in two randomized, placebo-controlled phase 3 ANNEXA registration studies.
Portola reported statistically significant results from the first part of the phase 3 ANNEXA-A study, which studied andexanet alfa administered as a single IV bolus dose with apixaban (Eliquis, Bristol-Myers Squibb/Pfizer) and from the first part of the phase 3 ANNEXA-R study with direct Factor Xa inhibitor rivaroxaban (Xarelto, Janssen Pharmaceuticals).
The ongoing second parts of both studies are evaluating a bolus plus a continuous infusion of andexanet alfa to maintain the reversal of anticoagulation activity.
In four different phase 2 proof-of-concept studies, andexanet alfa demonstrated immediate reversal of anticoagulation activity after apixaban, rivaroxaban, edoxaban and enoxaparin in healthy volunteers. Results also showed that activity of andexanet alfa could be sustained.
Portola plans to conduct a phase 2 proof-of-concept study with its investigational Factor Xa inhibitor betrixaban.
The FDA Office of Orphan Products Development grants orphan drug designation to novel drugs and biologics that are intended for the safe and effective treatment, diagnosis or prevention of rare diseases or disorders that affect fewer than 200,000 people in the United States.