Portola Announces Positive Data on Factor Xa Inhibitor in VTE Trial

Portola Pharmaceuticals has received positive results from EXPERT, a Phase II study of its oral Factor Xa inhibitor, PRT054021, for the prevention of venous thromboembolism (VTE) following total knee replacement surgery. Based on these results, Portola will advance PRT054021 into further clinical testing.

EXPERT enrolled more than 200 patients at 20 medical centers in the U.S. and Canada in a randomized, active comparator, parallel-group trial. Patients were randomized to receive one of two oral doses of PRT054021 or Lovenox (enoxaparin) given as a subcutaneous injection. The treatment period was for 10 to 14 days after surgery, at which time a venogram was obtained to determine the presence of VTE.

The EXPERT steering committee, which includes a group of leading physicians and orthopedic surgeons with significant experience in conducting clinical trials involving novel anticoagulants, determined that EXPERT met its objectives: PRT054021 appeared effective and safe at the two doses studied, and the results support advancing the compound into further clinical trials.

Portola expects to develop PRT054021 for additional indications including stroke prevention in patients with atrial fibrillation and secondary prevention of myocardial infarction and stroke. Factor Xa is a validated target, and inhibiting its activity is believed to have superior anticoagulant properties compared with other targets such as thrombin, according to the company. Portola believes its oral Factor Xa inhibitor will offer several advantages, including a long half-life to support once-daily dosing, and a low peak-to-trough concentration ratio, resulting in consistent activity that does not require monitoring or dose adjustment.