Cytokinetics’ focus to muscle biology has broad applicability over a number of therapeutic areas involving muscle contractility, including but not limited to heart failure, hypertension, frailty and asthma. Cytokinetics’ initial efforts in this area of research have been focused towards treatments for heart failure. Our expertise is built on an understanding of the key cytoskeletal proteins, myosin and actin. Cardiac myosin is the cytoskeletal protein in the cardiac cell that is directly responsible for converting chemical energy through the hydrolysis of ATP into the mechanical force that results in contraction. Cardiac muscle cell contractility is driven by the cardiac sarcomere, the fundamental unit of muscle contraction in the heart that is a highly ordered cytoskeletal structure composed of cardiac myosin, actin and a set of regulatory proteins. The sarcomere represents one of the most thoroughly characterized protein machines in human biology. Cytokinetics advanced its first drug candidate from this franchise area, CK-1827452, into the clinic in September 2005 for the potential treatment of acute heart failure.