Bristol-Myers Squibb, Pfizer and Portola partner to conduct clinical study of PRT4445 and ELIQUIS

Portola Pharmaceuticals, Inc., Bristol-Myers Squibb Company (NYSE: BMY) and Pfizer Inc. (NYSE: PFE) today announced a clinical collaboration agreement to conduct a proof-of-concept study of PRT4445 and the investigational oral Factor Xa inhibitor ELIQUIS^® (apixaban). PRT4445 is a universal Factor Xa inhibitor antidote in clinical development designed to reverse the anticoagulant activity of any Factor Xa inhibitor. No agents are approved to reverse the activity of Factor Xa inhibitors.

The collaboration will be in effect during the clinical proof-of-concept study, which is anticipated to start by the end of this year. The study is designed to demonstrate the safety of PRT4445 and its ability to reverse the anticoagulation activity of ELIQUIS and other Factor Xa inhibitors, including betrixaban, Portola's Phase 3 oral Factor Xa inhibitor. Bristol-Myers Squibb and Pfizer will make an undisclosed cash payment to Portola upon initiation of the proof-of-concept study with ELIQUIS and will provide development and regulatory guidance for the study. Portola retains 100 percent global development and commercialization rights for PRT4445.

"Oral Factor Xa inhibitors address an important unmet need for patients requiring anticoagulant therapy, but as with all anticoagulants, there is a need for an antidote to help manage the concerns physicians have around infrequent but serious bleeding events." said William Lis, chief executive officer of Portola. "This clinical collaboration brings together world-class expertise in the field of thrombosis from Bristol-Myers Squibb, Pfizer and Portola with the goal of accelerating the development of PRT4445 as an antidote to ELIQUIS, while allowing Portola to retain all rights to develop and commercialize the compound in the future."

"Patient safety and improved patient outcomes have guided our clinical development program for ELIQUIS, including our efforts to identify a reversal agent for urgent clinical situations," said Brian Daniels, senior vice president, Global Development and Medical Affairs, Bristol-Myers Squibb. "With our partner Pfizer, we look forward to working with Portola to advance the scientific understanding of the role of PRT4445 as a potential antidote for ELIQUIS."

Major bleeding events occur infrequently in patients taking Factor Xa inhibitors (1-4% per year in clinical studies) and standard measures are employed to manage these events. Development of an agent specifically designed to reverse the activity of Factor Xa inhibitors may provide an antidote for patients who, in rare instances, experience an uncontrolled major bleeding event or require emergency surgery.