What Was So Bad About Results Of Portola's APEX Trial For Betrixaban?

Shares of Portola Pharmaceuticals Inc PTLA plunged more than 27 percent to set a new 52-week low of $20 after the topline results of a late stage study showed that its oral treatment betrixaban was not statistically different than the standard therapy in preventing blood clots.

However, the company said a positive net clinical benefit with betrixaban was observed, providing a pathway for an NDA application later this year.

The company's Phase 3 APEX study evaluated the superiority of two anticoagulation medications, namely betrixaban and injectable enoxaparin for the prevention of blood clots in acute medically ill patients. These are patients who are hospitalized for serious common medical conditions, such as heart failure, stroke, infection and pulmonary disease.

"Cohort 1 achieved a p value of 0.054, which did not meet the threshold. Cohort 2 and the overall study population achieved p values of 0.029 and 0.006, respectively. There was no statistical difference in major bleeding between the betrixaban and enoxaparin arms in any of these three patient groups," Portola said in a press release.

However, according to the company, the number of fatal bleeds was balanced between the two arms, and the number of intracranial hemorrhages was numerically lower in the betrixaban arm.

"While we understand that the interpretation of these statistical and clinical results will be subject to discussions with regulatory agencies, we and the APEX Study academic leadership believe that the data in Cohort 1 were sufficiently strong to support a full assessment of Cohort 2 and the overall study population," Bill Lis, chief executive officer of Portola, said in a statement.

"We believe the overall robustness of the efficacy and safety results in this high-risk patient population, including the positive net clinical benefit observed, provide ample evidence to support the submission of an NDA later this year."

Shares of Portola plummeted 27.46 percent to $20.75. More than 9.8 million shares changed hands, compared to its three-month average volume of 769,513 shares.