Mast Therapeutics, Inc., formerly ADVENTRX Pharmaceuticals, Inc., is a development-stage company biopharmaceutical company focused on developing product candidates. The Company's product candidate is ANX-188, a rheologic, antithrombotic and cytoprotective agent that improves microvascular blood flow and has application in treating a range of diseases and conditions, such as complications arising from sickle cell disease. As of December 31, 2011, the Company also is developing ANX-514, a detergent-free formulation of the chemotherapy drug docetaxel. The Company offers ANX-188 (purified poloxamer 188), ANX-514 (docetaxel for injectable emulsion) and Exelbine (vinorelbine injectable emulsion). In April 2011, the Company acquired SynthRx, Inc. In February 2014, Mast Therapeutics Inc completed its acquisition of Aires Pharmaceuticals, Inc. Aires became a wholly-owned subsidiary of Mast Therapeutics.