New Data From Nonclinical Heart Failure Study To Be Presented At American Heart Association Conference

SAN DIEGO, Nov. 19, 2014 /PRNewswire/ -- Mast Therapeutics, Inc. (NYSE MKT: MSTX), a clinical-stage biopharmaceutical company, today announced that data from MST-188 (vepoloxamer), its lead product candidate, will be featured at the American Heart Association (AHA) Scientific Sessions 2014. Data will be presented as a poster during the session "Heart Failure Pharmacology: From the Membrane to the Mitochondria." The AHA conference is being held at the McCormick Place Convention Center in Chicago through November 19.

Brian M. Culley, Chief Executive Officer, said: "These data further support the MST-188 development rationale in heart failure and reinforce our belief that MST-188 represents a novel approach to treating a condition that results in over one million hospitalizations each year in the U.S. alone. We look forward to exploring the potential of MST-188 in this area of significant unmet medical need through a Phase 2 study in patients with acute decompensated heart failure, which we expect will begin recruiting patients in the first half of 2015."

The poster presented at AHA includes new data from the Company's randomized, placebo-controlled, nonclinical study of MST-188 (vepoloxamer) (low dose and high dose) in a model of chronic heart failure. In the study, a single, two-hour infusion of MST-188 significantly reduced plasma levels of tumor necrosis factor-α (TNF-α), interlukin-6 (IL-6), C-reactive protein (CRP) and matrix metalloproteinase-2 (MMP-2), at both one week and two weeks after MST-188 administration. Earlier this year, the Company reported that, in the same study, MST-188 significantly improved key metrics of left ventricular systolic function, which improvements were immediate (at the end of MST-188 administration) and remained significant at one week (and, in some cases, at two weeks) post-treatment. In addition, data from the same study revealed that MST-188 significantly reduced troponin-I and plasma N-terminal pro-brain natriuretic peptide (NT-proBNP), at both one week and two weeks post-treatment.

Poster Information:

The poster entitled "Short (2 hour) Intravenous Infusion of Vepoloxamer (MST-188) Elicits Prolonged (1-2 weeks) Improvement in Biomarkers in Dogs with Advanced Heart Failure" will be presented by Hani N. Sabbah, Ph.D., Professor of Medicine & Director of Cardiovascular Research at the Henry Ford Health System in Detroit, Michigan
The poster is available on the Company's website at: http://www.masttherapeutics.com/technology/publications/

About Mast Therapeutics
Mast Therapeutics, Inc. is a publicly traded biopharmaceutical company headquartered in San Diego, California. The Company is leveraging the MAST (Molecular Adhesion and Sealant Technology) platform, derived from over two decades of clinical, nonclinical and manufacturing experience with purified and non-purified poloxamers, to develop MST-188 (vepoloxamer), its lead product candidate, for serious or life-threatening diseases and conditions typically characterized by impaired microvascular blood flow and damaged cell membranes.

The Company is enrolling subjects in EPIC, a pivotal Phase 3 study of MST-188 in sickle cell disease, and in a Phase 2 study to evaluate whether MST-188 improves the effectiveness of recombinant tissue plasminogen activator therapy in patients with acute limb ischemia. The Company also is planning to initiate a Phase 2 clinical study of MST-188 in patients with acute decompensated heart failure in the first half of 2015. More information can be found on the Company's web site at www.masttherapeutics.com. (Twitter: @MastThera)

Mast Therapeutics™ and the corporate logo are trademarks of Mast Therapeutics, Inc.

Forward Looking Statements
Mast Therapeutics cautions you that statements included in this press release that are not a description of historical facts are forward-looking statements that are based on the Company's current expectations and assumptions. Such forward-looking statements include, but are not limited to, statements relating to prospects for successful development of the Company's product candidates, including MST-188 (vepoloxamer) in heart failure, and anticipated timing of achievement of development milestones, including commencement of clinical studies. Among the factors that could cause or contribute to material differences between the Company's actual results and the expectations indicated by the forward-looking statements are risks and uncertainties that include, but are not limited to: the uncertainty of outcomes in ongoing and future studies of the Company's product candidates and the risk that its product candidates, including MST-188, may not demonstrate adequate safety, efficacy or tolerability in one or more such studies, including EPIC; delays in the commencement or completion of clinical studies, including as a result of difficulties in obtaining regulatory agency agreement on clinical development plans or clinical study design, opening trial sites, enrolling study subjects, manufacturing sufficient quantities of clinical trial material, being subject to a "clinical hold," and/or suspension or termination of a clinical study, including due to patient safety concerns or lack of funding; the potential for institutional review boards or the FDA or other regulatory agencies to require additional nonclinical or clinical studies prior to initiation of a planned clinical study of a product candidate; the risk that, even if clinical studies are successful, the FDA or other regulatory agencies may determine they are not sufficient to support a new drug application; the potential that, even if clinical studies of a product candidate in one indication are successful, clinical studies in another indication may not be successful; the Company's reliance on contract research organizations (CROs), contract manufacturing organizations (CMOs), and other third parties to assist in the conduct of important aspects of development of its product candidates, including clinical studies, manufacturing, and regulatory activities for its product candidates, and that such third parties may fail to perform as expected; the Company's ability to obtain additional funding on a timely basis or on acceptable terms, or at all; the potential for the Company to delay, reduce or discontinue current and/or planned development activities, including clinical studies, partner its product candidates at inopportune times or pursue less expensive but higher-risk and/or lower return development paths if it is unable to raise sufficient additional capital as needed; the risk that, even if the Company successfully develops a product candidate in one or more indications, it may not realize commercial success with its products and may never generate revenue sufficient to achieve profitability; the risk that the Company is not able to adequately protect its intellectual property rights relating to the MAST platform and MST-188 or AIR001 and prevent competitors from duplicating or developing equivalent versions of its product candidates; and other risks and uncertainties more fully described in the Company's press releases and periodic filings with the Securities and Exchange Commission. The Company's public filings with the Securities and Exchange Commission are available at www.sec.gov.

You are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date when made. Mast Therapeutics does not intend to revise or update any forward-looking statement set forth in this press release to reflect events or circumstances arising after the date hereof, except as may be required by law.