(PTLA) to Present Results of Phase 3 APEX Study of Betrixaban

–Company Plans to Submit NDA and MAA for Betrixaban in Second Half of 2016–

–Webcast with APEX Study Executive Committee Members Today at 11 a.m. ET–

MONTPELLIER, France, and SOUTH SAN FRANCISCO, Calif. , May 27, 2016  — Portola Pharmaceuticals Inc.^® (NASDAQ:PTLA) announced that the full results of its pivotal Phase 3 APEX (Acute Medically Ill VTE Prevention with Extended Duration Betrixaban) Study were presented today for the first time in a late-breaking clinical trial session (http://investors.portola.com/) at the 62^nd Annual International Society on Thrombosis and Haemostasis (ISTH) Scientific and Standardization Committee (SSC) Meeting. Full results from the APEX trial were published simultaneously online in The New England Journal of Medicine (http://www.nejm.org/doi/full/10.1056/NEJMoa1601747). Portola announced topline results (http://topline.portola.com) from the APEX trial in March 2016.

APEX, which enrolled 7,513 patients at more than 450 clinical sites worldwide, assessed the superiority of extended-duration betrixaban for 35 days compared to standard-duration enoxaparin for 10+4 days. The trial was designed in cooperation with the FDA and EMA to incorporate a novel patient enrichment and statistical analysis plan derived from the 2012 FDA guidance document on enrichment strategies for clinical trials.

“In a pre-specified subgroup of medically ill patients who were D-dimer positive, extended- duration betrixaban demonstrated a reduction in VTE events approaching statistical significance. In the pre-specified exploratory analyses of central lab D-dimer values and in progressively larger cohorts, including all study patients, the data demonstrated a consistent and significant reduction in VTE with betrixaban with no statistical difference in major bleeding between the betrixaban and enoxaparin arms,” said C. Michael Gibson, M.S., M.D., senior author of the NEJM publication and APEX Executive Committee Member and Steering Committee Chairman.

Betrixaban, an investigational drug, is an oral, once-daily Factor Xa inhibitor anticoagulant. It is an FDA-designated Fast Track therapy for extended-duration VTE prophylaxis in acute medically ill patients. Acute medically ill patients are hospitalized for serious common medical conditions, such as heart failure, stroke, infection and pulmonary disease. Despite the use of standard of care anticoagulation, a significant number of patients will suffer a VTE event. Over half of these events will occur after discontinuation of enoxaparin and hospital discharge. Currently no anticoagulant, including any of the marketed oral Factor Xa inhibitors, is approved or guideline-recommended for extended-duration VTE prophylaxis in this patient population.

“The APEX Study results show consistent evidence that VTE events can be reduced with betrixaban with no statistical difference in major bleeding between the betrixaban and enoxaparin arms. This is particularly true for the most clinically relevant symptomatic disease where we observed a 30 to 45 percent reduction in events over the duration of the study,” said lead author of the NEJM publication Alexander (Ander) T. Cohen, MBBS, M.Sc., M.D., FRACP, APEX Co-Principal Investigator and Co-Chairman of the APEX Executive Committee and Consultant Physician at Guy’s and St Thomas’ NHS Foundation Trust. “Such meaningful results in an area where there is currently no available recommended therapy offer important potential benefits for public health worldwide. Based on the number of reduced events in APEX, this could translate into preventing over 100,000 additional VTE events per year and over 50,000 deaths from pulmonary embolism in the G7 countries if betrixaban is approved.”

Later this year, Portola plans to submit the APEX Study data as part of a New Drug Application (NDA) for betrixaban in the United States and as part of a Marketing Authorization Application (MAA) in the EU.

“We recently held a pre-NDA meeting with the FDA where we reconfirmed Fast Track Designation for betrixaban in this indication and agreed to upcoming meetings in preparation for an NDA submission in the second half of 2016,” said Bill Lis, chief executive officer of Portola.

About VTE in Acute Medically Ill Patients
An estimated 20 million acute medically ill patients in the G7 countries are at risk of developing VTE either while in the hospital or following discharge. Each year, more than 1 million VTEs and 150,000 VTE-related deaths occur in acute medically ill patients in the G7 countries, despite the standard use of injectable enoxaparin and other heparins in the hospital. Although more than half of VTE events occur after the patient is discharged from the hospital, no anticoagulant, including enoxaparin or any of the marketed oral Factor Xa inhibitors, is approved for extended VTE prophylaxis in the more than 24 million medically ill patients hospitalized in the G7 countries annually.

About Betrixaban
Betrixaban directly inhibits the activity of Factor Xa, an important validated target in the blood coagulation pathway, to prevent life-threatening thrombosis. Betrixaban has distinct properties that may allow it to demonstrate clinical benefit without the significant imbalance in the risk of major bleeding seen with other agents in the class. These include a 19-25-hour half-life for once-daily dosing; a low peak-to-trough drug concentration ratio that minimizes anticoagulant variability; low renal clearance; and no significant CYP3A4 metabolism, which may reduce the risk of drug-drug interactions.

Webcast Details
Portola will host an investor event today, May 27, 2016, at 5:00-6:00 p.m. CEST/11 a.m.-12 p.m. EDT in which members of the Company’s senior management team and Drs. Gibson and Cohen will present and discuss the full APEX Study data. Webcast participants will be able to participate in a live Q&A session via the webcast portal. To access the webcast of the live event, go to the Investor Relations section of the Company’s website at investors.portola.com. A replay will be available on the Company’s website for 30 days following the live event, also at investors.portola.com.

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 three programs, including betrixaban, an oral, once-daily Factor Xa inhibitor; AndexXa™ (andexanet alfa), a recombinant protein designed to reverse the anticoagulant effect in patients treated with an oral or injectable Factor Xa inhibitor; and cerdulatinib, a Syk/JAK inhibitor in development to treat hematologic cancers. Portola’s partnered program is focused on developing selective Syk inhibitors for inflammatory conditions. For more information, visit portola.com and follow the Company on Twitter @Portola_Pharma.

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 the potential for study results to support an application for regulatory approval of betrixaban, the potential for betrixaban, subject to regulatory approval, to play a role in both in-hospital and post-discharge reduction of VTE events and deaths, our interpretation and characterization of APEX Study results and the anticipated timing of our submission of filings seeking regulatory approval. Risks that contribute to the uncertain nature of the forward-looking statements include the results of discussions with regulatory authorities regarding interpretation of full APEX Study results, that the FDA and other regulatory authorities may not approve betrixaban, whether the clinical results of betrixaban will meet the regulatory requirements for approval, whether regulatory submissions will occur or will be submitted in a timely manner and that marketing approvals may not be granted or, if granted, may have significant limitations on their use or require additional studies. These and other risks and uncertainties are described more fully in our most recent filings with the Securities and Exchange Commission, including our most recent quarterly report on Form 10-Q, which was filed on May 6, 2016. All forward-looking statements contained in this press release speak only as of the date on which they were made. We undertake no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made.

 

Investor Contact: 
Ana Kapor 
Portola Pharmaceuticals
ir@portola.com
1.650.246.7252 

Media Contact:
Julie Normart
W2O Group
jnormart@w2ogroup.com
1.559.974.3245