Portola's andexanet alfa reverses Xarelto activity

Portola Pharmaceuticals Inc. (NASDAQ:PTLA) said in a Phase II trial a single IV bolus of andexanet alfa ( PRT064445) dose-dependently reversed the anticoagulant activity of Xarelto rivaroxaban from Bayer AG (Xetra:BAYN) and partner Johnson & Johnson (NYSE:JNJ). In 18 healthy volunteers who had taken once-daily oral Xarelto for six days, 210 mg andexanet alfa reversed the anticoagulant activity of Xarelto by 20% within two minutes of being administered. The 420 mg dose of andexanet alfa reversed the anticoagulant activity by 53%. Portola plans to start Phase III testing with andexanet alfa -- a recombinant protein designed to reverse anticoagulant activity of Factor Xa inhibitors -- in 2014. The company was up $2.18 to $26.80 on Monday. ...