Portola Pharmaceuticals Announces Initiation of Phase 1/2 Clinical Study of PRT2070

Portola Pharmaceuticals Logo

SOUTH SAN FRANCISCO, Calif., Oct. 9, 2013 (GLOBE NEWSWIRE) -- Portola Pharmaceuticals, Inc. (Nasdaq:PTLA) today announced that it has initiated a Phase 1/2 clinical study of PRT2070, a novel, oral, dual spleen tyrosine kinase (Syk) and janus kinase (JAK) inhibitor. The compound is being developed for patients with genetically-defined hematologic cancers, as well as for patients who have failed therapy due to relapse or acquired mutations. PRT2070's dual mechanism of action, which targets two validated pathways for tumor survival and proliferation, has strong scientific rationale in these settings, where other compounds have failed to demonstrate clinical benefit.

"We are pleased to advance our third wholly-owned program focused on addressing an unmet medical need into the clinic. Our goal with PRT2070 is to develop an effective and well- tolerated oral drug for the thousands of lymphoma and leukemia patients who are impacted by difficult- to-treat genetic subtypes or who become unresponsive to available therapies," said John T. Curnutte, M.D., Ph.D., executive vice president of research and development for Portola. "With PRT2070, we have seen promising in vitro activity in cell lines with specific mutations and in tumor cells that have lost sensitivity to other compounds due to acquired mutations. We look forward to seeing initial clinical data for this agent in 2014."

The open-label, multicenter, Phase 1/2 proof-of-concept study will assess the safety, pharmacokinetics, pharmacodynamics and clinical activity of oral PRT2070. In the multi-dose, dose-escalation Phase 1 part of the study, PRT2070 will be administered to sequential dose cohorts at increasing dose levels until the maximum tolerated dose is identified. The Phase 1 portion of the study can include patients with relapsed or refractory chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma and non-Hodgkin lymphoma (NHL) (including diffuse large B-cell lymphoma, follicular lymphoma and mantle cell lymphoma). The Phase 2 part of the study is a cohort expansion that will evaluate measures of safety and efficacy in cancer types identified based on the responses seen in the dose-escalation phase. Portola has engaged the Sarah Cannon Research Institute, a global strategic research organization based in Nashville, Tenn., to conduct the study.

About PRT2070

PRT2070 is an oral, potent inhibitor of both the B-cell receptor (BCR) pathway (via Syk) and important cytokine signaling (via JAK) that promote survival and proliferation of hematologic cancers, such as chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL), and are also implicated in autoimmune diseases. PRT2070 is unique in that it simultaneously targets these two validated pathways in one therapy, which may particularly distinguish it in difficult-to-treat patient populations with certain genetic subtypes, such as diffuse large B-cell lymphoma (including patients with identified mutations) and in patients who have failed therapy due to relapse or acquired mutations.

Portola is currently evaluating PRT2070 in a Phase 1/2 clinical study and has worldwide rights to develop and commercialize the agent for hematologic cancers and other systemic indications. Rights for certain nonsystemic indications are shared 50/50 with Aciex Therapeutics.

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 trauma, 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 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 the use of PRT2070 as a kinase inhibitor and any of Portola's clinical trials, including Portola's Phase 1/2 proof-of-concept study for PRT2070. 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; 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. 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.

*PRT4445 has a proposed International Nonproprietary Name (pINN) of andexanet alfa.

CONTACT: Investor Contact: Alexandra Santos Portola Pharmaceuticals ir@portola.com 650.246.7239 Media Contact: Joey Fleury BrewLife jfleury@brewlife.com 415.946.1090

Source:Portola Pharmaceuticals