Portola Pharmaceuticals Announces Upcoming Data Presentations on Andexanet Alfa at International Society on Thrombosis and Haemostasis (ISTH) 2015 Congress

Full Results of Second Part of ANNEXA(TM) Apixaban Study and Results of Andexanet Alfa Vs. Four-Factor Prothrombin Complex Concentrate Study to be Featured in Oral Sessions


SOUTH SAN FRANCISCO, Calif., June 9, 2015 (GLOBE NEWSWIRE) -- Portola Pharmaceuticals (Nasdaq:PTLA) today announced that data from its clinical development program for the investigational agent andexanet alfa will be highlighted in oral sessions at the upcoming International Society on Thrombosis and Haemostasis (ISTH) 2015 Congress, which is taking place from June 20-25 in Toronto. Andexanet alfa, a U.S. Food and Drug Administration (FDA)-designated breakthrough therapy, is a recombinant protein specifically designed to reverse the anticoagulant activity in patients treated with an oral or injectable Factor Xa inhibitor.

Full results from the second part of the Phase 3 ANNEXA™-A (Andexanet Alfa a Novel Antidote to the Anticoagulant Effects of FXa Inhibitors – Apixaban) study will be presented in a late- breaking abstract oral session. This registration-enabling study evaluated the safety and efficacy of andexanet alfa administered as an intravenous bolus followed by a continuous two-hour infusion to sustain the reversal of anticoagulation activity of the Factor Xa inhibitor apixaban in healthy volunteers. Data from a study comparing andexanet alfa with a four-factor prothrombin complex concentrate (PCC) in reversing the anticoagulation activity of the Factor Xa inhibitor rivaroxaban in an animal model of bleeding will be presented in a separate oral session. Additionally, data from a study evaluating the interaction of andexanet alfa with tissue factor pathway inhibitor on Factor Xa inhibitor-induced anticoagulation will be presented in a poster session.

The abstracts are now available at http://www.isth.org/page/2015AbstractOnline. Following are details of the presentations, which will include additional data not currently available in the published abstracts.

Abstract Title: ANNEXA™-A Part 2: A Phase 3 randomized, double-blind, placebo-controlled trial demonstrating sustained reversal of apixaban-induced anticoagulation in older subjects by andexanet ALFA (PRT064445), a universal antidote for factor Xa (FXA) inhibitors (abstract #LB004)
Presenting Author:  Mark Crowther, M.D., M.Sc., associate chair, Department of Medicine, McMaster University, Hamilton, Ontario
Oral Session Title: Late-Breaking Abstract Session – Thrombosis and Anticoagulation
Presentation Date, Time and Location: Monday, June 22, at 8:45 a.m. ET, Exhibit Hall G & F 
   
Abstract Title: Andexanet alfa but not four-factor prothrombin complex concentrate reverses rivaroxaban-induced anticoagulation as measured by reduction in blood loss in a rabbit liver laceration model (abstract #OR318)
Presenting Author:  Polly Pine, Ph.D., head of pharmacology, Portola Pharmaceuticals
Oral Session Title NOACs and Reversal
Presentation Date, Time and Location: Wednesday, June 24, at 2:30 p.m. ET, Exhibit Hall G & F
   
Abstract Title: Interaction of andexanet alfa, a universal antidote to fXA inhibitors, with tissue factor pathway inhibitor enhances reversal of fXA inhibitor-induced anticoagulation (abstract #PO351-TUE)
Presenting Author:  Genmin Lu, Ph.D., senior scientist, Portola Pharmaceuticals
Poster Session Title:  Non-vitamin K Antagonist Oral Anticoagulants II 
Presentation Date, Time and Location: Tuesday, June 23, from 6:00-7:30 p.m. ET, Exhibition Area in Hall D, E


About Portola Pharmaceuticals, Inc.

Portola Pharmaceuticals is a biopharmaceutical company developing product candidates that could significantly advance the fields of thrombosis and other hematologic diseases. The Company is advancing its three wholly-owned programs using novel biomarker and genetic approaches that may increase the likelihood of clinical, regulatory and commercial success of its potentially life-saving therapies. Portola's partnered programs are focused on developing selective Syk inhibitors for inflammatory conditions.

Betrixaban

Portola's wholly-owned, oral, once-daily Factor Xa inhibitor betrixaban is being evaluated in the only biomarker-based Phase 3 study for hospital-to-home prophylaxis of venous thromboembolism (VTE) in acute medically ill patients. Betrixaban's distinct properties may have the potential to allow the agent to demonstrate efficacy without the significant increase in the rate of major bleeding that was seen in this patient population with other Factor Xa inhibitors. If approved, betrixaban could be the first anticoagulant for both hospital and post-discharge VTE prophylaxis and the standard of care in this large market of more than 20 million patients in the G7 countries alone.

Andexanet Alfa

Andexanet alfa, an FDA-designated breakthrough therapy, is a recombinant protein designed to reverse the anticoagulant effect in patients treated with an oral or injectable Factor Xa inhibitor. Andexanet alfa has the potential to be a first-in-class antidote for anticoagulated patients who suffer a major bleeding episode or require emergency surgery. Portola has entered into Phase 3 clinical collaboration agreements with all of the manufacturers of direct Factor Xa inhibitors while retaining all commercial rights to andexanet alfa. The Company is currently evaluating andexanet alfa in the Phase 3 and Phase 4 ANNEXA™ (Andexanet Alfa a Novel Antidote to the Anticoagulant Effects of FXa Inhibitors) registration studies.

Cerdulatinib

Portola's product candidate in the area of hematologic cancer, cerdulatinib, is an orally available molecule that uniquely inhibits two validated tumor proliferation pathways – spleen tyrosine kinase (Syk) and janus kinase (JAK). It is currently being evaluated in a Phase 1/2a proof-of-concept study in patients with B cell leukemias or lymphomas with a focus on genetically-defined subtypes, as well as in patients who have failed therapy due to relapse or acquired mutations.

For more information, visit www.portola.com and follow the Company on Twitter @Portola_Pharma.

Forward-looking Statement

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: Portola's plans for future clinical studies and pursuit of an Accelerated Approval process for andexanet alfa, anticipated growth in the market for anticoagulants, the potential indications, efficacy, safety and activity of andexanet alfa, and the potential market and indications for its other product candidates. 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 trials; the success of Portola's clinical trials and the demonstrated efficacy of Portola's product candidates thereunder; the accuracy of Portola's estimates regarding its expenses and capital requirements; Portola's ability to manufacture andexanet alfa; regulatory developments in the United States and foreign countries; Portola's ability to obtain and maintain intellectual property protection for its product candidates; and the loss of 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, including its Annual Report on Form 10-K, which was filed on May 7, 2015. 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.



            

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