Mast Therapeutics Announces Positive Data In Model Of Heart Failure

- Statistically significant improvement in key parameters of heart function, including left ventricular ejection fraction and cardiac output

SAN DIEGO, Jan. 6, 2014 /PRNewswire/ -- Mast Therapeutics, Inc. (NYSE MKT: MSTX) today announced that, in a placebo-controlled, nonclinical model of chronic heart failure, MST-188 demonstrated a statistically significant improvement in numerous parameters of heart function, including left ventricular ejection fraction and end-systolic volume, stroke volume and cardiac output.  Notably, a single two-hour infusion of MST-188 resulted in improvements that were significant immediately (at the end of MST-188 administration) and remained significant at one week (and, in some cases, at two weeks) after MST-188 administration. 

Hani N. Sabbah, Ph.D., Professor of Medicine & Director of Cardiovascular Research at Henry Ford Health System, said: "These data clearly show that MST-188 improves left ventricular ejection fraction and end-systolic volume, both of which are important indicators of long-term mortality and morbidity in chronic heart failure, with some effects lasting up to 2 weeks post-infusion.  The durability of response is very encouraging and merits clinical investigation."

Santosh Vetticaden, M.D., Ph.D., Chief Medical Officer of Mast Therapeutics, said: "Heart failure is an area of significant unmet medical need that accounts for over 1 million hospitalizations every year in the U.S. alone.  Although there have been modest improvements in treatment, heart failure remains associated with significant mortality and high rates of hospital admission and readmission.  We look forward to discussing these results with heart failure experts and potential partners and mapping our clinical development strategy in this exciting new indication." 

The Company has submitted data from this study for presentation at an upcoming medical conference and will provide an update on its plans for MST-188 in heart failure later in 2014. 

Details of the Study and Results
The objective of the study was to determine the effect of acute intravenous administration of MST-188 on left ventricular systolic and diastolic cardiac function in a model of chronic heart failure produced by multiple sequential intracoronary microembolizations.  A single dose of MST-188 (low or high dose) or placebo was administered over 2 hours.  Hemodynamic, ventriculographic, echocardiographic and electrocardiographic measurements were taken at baseline (prior to study drug administration) and at the following time-points after the start of study drug administration: 2 hours (end of administration), 24 hours, 1 week and 2 weeks.  Peripheral venous blood samples were obtained at the same time-points.  The improvements described above were calculated as the difference between baseline and mean values of each study group at each time-point using a one-way analysis of variance, with p<0.05 considered significant.  The study was conducted under the supervision of Dr. Hani N. Sabbah at Henry Ford Health System, a Michigan non-profit corporation. 

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, its lead product candidate, for serious or life-threatening diseases with significant unmet needs.  MST-188 is a cytoprotective, hemorheologic, anti-inflammatory and anti-thrombotic agent that has potential utility in diseases or conditions characterized by microcirculatory insufficiency (endothelial dysfunction and/or impaired blood flow). 

The Company is enrolling subjects in EPIC, a pivotal phase 3 study of MST-188 in sickle cell disease.  In early 2014, the Company plans to initiate a phase 2, clinical proof of concept study in acute limb ischemia that will evaluate whether MST-188 improves the effectiveness of existing thrombolytic agents.  The Company also is evaluating development options in heart failure.  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 regarding MST-188's prospects in heart failure, the potential market in that indication, and the Company's development plans for MST-188 in heart failure and in acute limb ischemia, including the timing of initiation of any 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: 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 any planned phase 2 clinical study of MST-188; the uncertainty of outcomes in ongoing and future studies of MST-188 and the risk that MST-188 may not demonstrate adequate safety, efficacy or tolerability in one or more such studies; the potential that, even if clinical studies of MST-188 in one indication are successful, clinical studies in another indication may not be successful; 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 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 MST-188, including clinical studies, and regulatory activities for MST-188, 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 MST-188 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 MST-188 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 and prevent competitors from duplicating or developing equivalent versions of its product candidates, including MST-188; 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.

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SOURCE Mast Therapeutics, Inc.

Ioana C. Hone, ir@mastthera.com, 858-552-0866 Ext. 303