SAN DIEGO, Nov. 13, 2013 /PRNewswire/ -- Mast Therapeutics, Inc. (NYSE MKT: MSTX) today announced that the U.S. Food and Drug Administration (FDA) has designated MST-188 for the treatment of acute limb ischemia as an orphan drug. Brian M. Culley, Chief Executive Officer, said: "This designation represents further progress in our development of MST‑188 as an adjunct therapy for life-threatening conditions treated with existing thrombolytic agents, such as tPA. As we previously reported, we are on track to initiate a phase 2, clinical proof-of-concept study in acute limb ischemia in early 2014. If this study demonstrates that MST-188 improves the 'clot busting' activity of tPA in acute limb ischemia, we believe it would provide the data to design a registrational phase 3 study in that orphan disease, as well as generate data to support development in indications with even larger market opportunities, such as stroke." 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, a genetic blood disorder in which sickled cells cause blood flow problems, which can lead to severe pain, irreversible organ damage, and early death. The Company plans to initiate a phase 2 clinical study of MST-188 in acute limb ischemia, a complication of peripheral arterial disease, in early 2014. 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.