Portola Pharma Announces Positive Phase 2 Data With Andexanet Alfa

(RTTNews) - Portola Pharmaceuticals (PTLA) reported positive data from Phase 2 study in healthy volunteers, which showed that andexanet alfa, an FDA-designated breakthrough therapy, can reverse a low molecular weight heparin, thereby expanding its potential use to enoxaparin-treated patients.

Andexanet alfa is a first-in-class Factor Xa inhibitor antidote and is being developed as a direct reversal agent for patients receiving a Factor Xa inhibitor who suffer a major bleeding episode or who may require emergency surgery.

The Phase 2 proof-of-concept study was a randomized, double-blind, placebo-controlled, dose-escalation trial where 27 healthy volunteers were administered enoxaparin 40 mg subcutaneously once daily for six days and then randomized in a 2:1 ratio to andexanet alfa administered as an IV bolus or to placebo. Enoxaparin is an indirect inhibitor of Factor Xa, and results showed that anti-Factor Xa activity was reduced within two minutes to a level below the established enoxaparin therapeutic anticoagulation threshold.

Currently, millions of patients are treated with Factor Xa inhibitors for short-term use or chronic conditions, and the anticoagulant market is expected to continue to grow.