ATOMIC-AHF and COSMIC-HFATOMIC-AHF is a completed Phase 2 clinical trial designed to evaluate an intravenous formulation of omecamtiv mecarbil in 613 patients enrolled in three sequential, ascending-dose cohorts. In each cohort, patients were randomized 1:1 to omecamtiv mecarbil or placebo. The primary objective of this trial was to evaluate the effect of 48 hours of intravenous omecamtiv mecarbil compared to placebo on dyspnea in patients with left ventricular systolic dysfunction hospitalized for acute heart failure. The secondary objectives were to assess the safety and tolerability of the three dose levels of omecamtiv mecarbil compared with placebo and to evaluate the effects of 48 hours of treatment with intravenous omecamtiv mecarbil on additional clinical and pharmacodynamic measures.Oral formulations of omecamtiv mecarbil are currently being evaluated in a Phase 2 trial known as COSMIC-HF ( Chronic Oral Study of Myosin Activation to Increase Contractility in Heart Failure). COSMIC-HF is a double-blind, randomized, placebo-controlled, multicenter, dose escalation study designed to evaluate the safety and efficacy of omecamtiv mecarbil in approximately 420 patients with chronic heart failure and left ventricular systolic dysfunction. ATOMIC-AHF and COSMIC-HF are clinical trials of omecamtiv mecarbil conducted by Amgen in collaboration with Cytokinetics. Amgen holds an exclusive, worldwide license to develop and commercialize omecamtiv mecarbil and related compounds, subject to Cytokinetics' specified development and commercialization participation rights. Additional information about clinical trials of omecamtiv mecarbil can be found at www.clinicaltrials.gov. About Omecamtiv Mecarbil Omecamtiv mecarbil is a novel cardiac myosin activator and is the subject of a collaboration between Cytokinetics and Amgen. Cardiac myosin is the cytoskeletal motor protein in the cardiac muscle cell that is directly responsible for converting chemical energy into the mechanical force resulting in cardiac contraction. Cardiac myosin activators are thought to accelerate the rate-limiting step of the myosin enzymatic cycle and shift the enzymatic cycle in favor of the force-producing state. Preclinical research has shown that cardiac myosin activators increase contractility in the absence of changes in intracellular calcium in cardiac myocytes.