About Portola Pharmaceuticals, Inc.Portola Pharmaceuticals is a biopharmaceutical company focused on the development and commercialization of novel therapeutics in the areas of thrombosis, other hematologic disorders and inflammation. Portola's wholly-owned lead compound, betrixaban, is a novel, oral, once-daily Factor Xa inhibitor in Phase 3 development for extended-duration prophylaxis of a form of thrombosis known as venous thromboembolism (VTE) in acute medically ill patients. Currently, there is no anticoagulant approved for extended-duration VTE prophylaxis in this population. Portola's second lead development candidate, andexanet alfa (PRT4445*), has the potential to be the first universal antidote to reverse the effects of Factor Xa inhibitors in patients who suffer an uncontrolled bleeding episode or who require emergency surgery. Portola retains full, worldwide commercial rights to andexanet alfa. Portola's third product candidate, PRT2070, is an orally available kinase inhibitor that uniquely inhibits two validated tumor proliferation pathways -- spleen tyrosine kinase (Syk) and janus kinase (JAK). It is currently being studied in patients with genetically-defined hematologic cancers, as well as for patients who have failed therapy due to relapse or acquired mutations. Portola's fourth program is partnered with Biogen Idec and is focused on the development of PRT2607, a selective Syk inhibitor. For more information, visit www.portola.com . Forward-looking statements Statements contained in this press release regarding matters that are not historical facts are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements regarding andexanet alfa's potential efficacy, safety, duration of activity and potential to reverse the effects of all Factor Xa inhibitors, our plans for future clinical studies and pursuit of an Accelerated Approval process for andexanet alfa and anticipated growth in the market for anticoagulants. Risks that contribute to the uncertain nature of the forward-looking statements include: the accuracy of Portola's estimates regarding its ability to initiate and/or complete its clinical studies; the success of Portola's clinical studies and the demonstrated efficacy of Portola's product candidates thereunder; regulatory developments in the United States and foreign countries; and Portola's ability to attract and retain key scientific or management personnel. These and other risks and uncertainties are described more fully in Portola's most recent filings with the Securities and Exchange Commission. All forward-looking statements contained in this press release speak only as of the date on which they were made. Portola undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made.