Results From Two Completed Studies Support Further Clinical Development

SOUTH SAN FRANCISCO, CA -- (Marketwire) -- 06/01/09 -- Cytokinetics, Incorporated (NASDAQ: CYTK) announced today that data from two Phase IIa clinical trials evaluating CK-1827452 were presented in the Late Breaking Trials Session and in two poster presentations at the 2009 Heart Failure Congress of the European Society of Cardiology, held May 30-June 2, 2009 in Nice, France. The company believes these results support further clinical development of CK-1827452. Amgen Inc. has exercised its option and has obtained an exclusive, world-wide (except Japan) license to CK-1827452, subject to specified development and commercialization participation rights retained by Cytokinetics.

"I am pleased to have the opportunity to present these data from the first Phase IIa clinical trial of this novel mechanism compound in a Late Breaking Session at the 2009 Heart Failure Congress of the European Society of Cardiology. This rigorously conducted trial of CK-1827452 has generated interesting results consistent with the novel mechanism of action of this drug and support its further development as a possible treatment for patients with heart failure," stated Dr. John McMurray MD, FACC, FRCP, FESC, Professor of Medical Cardiology at the University of Glasgow in Glasgow, Scotland, United Kingdom.

"Data from these key Phase IIa clinical trials evaluating CK-1827452 support our therapeutic hypothesis for this potentially important new drug candidate in this complex disease population," stated Andrew A. Wolff, MD, FACC, Cytokinetics' Senior Vice President of Clinical Research and Development and Chief Medical Officer. "We believe these two clinical trials, together with others we have conducted with CK-1827452, have established a solid basis for further clinical development."

Late Breaking Trials Session

A Late Breaking Trials presentation titled "The Selective Cardiac Myosin Activator, CK-1827452, Increases Systolic Function in Heart Failure" was presented on Monday, June 1, by John McMurray, MD, FACC, FRCP, FESC, Professor of Medical Cardiology at the University of Glasgow in Glasgow, Scotland, United Kingdom. The clinical trial was multi-center, double-blind, randomized, and placebo-controlled. Its primary objective was to evaluate the safety and tolerability of CK-1827452 administered as an intravenous infusion to stable heart failure patients. Its secondary objectives were to establish a relationship between plasma concentration and pharmacodynamic effect of CK-1827452 and to determine the pharmacokinetics of CK-1827452 in this population. Overall, a total of 151 treatment periods were initiated in 45 patients.

The authors concluded that CK-1827452 significantly increases systolic ejection time, stroke volume, and ejection fraction calculated by a hybrid method employing Doppler-derived stroke volume in a concentration dependent manner. Statistically significant increases were demonstrated in systolic ejection time at plasma concentrations greater than 100 ng/mL, in stroke volume at plasma concentrations greater than 200 ng/mL, and in hybrid ejection fraction at plasma concentrations greater than 300 ng/mL. At plasma concentrations greater than 400 ng/mL, increases in stroke volume appeared to plateau in association with a concentration-dependent decline in heart rate. In addition, the data demonstrated statistically significant correlations between increasing CK-1827452 plasma concentration and decreases in left ventricular end-systolic volume and left ventricular end-diastolic volume. For the patients that were tolerant of all study drug infusions, no consistent pattern of adverse events with either dose or duration of infusion emerged.

This presentation included the first public disclosure of analyses showing that patients with reduced stroke volumes ( < 50 mL) at baseline had pharmacodynamic responses to CK-1827452 that were generally greater than those in patients with greater stroke volumes at baseline, demonstrating robust pharmacodynamic activity in this more severely affected sub-population of patients from the study. The authors concluded that these findings support further study and translation of this novel mechanism into patients with heart failure.

Poster Presentations

A poster titled "Echocardiographic Detection of Increases in Ejection Fraction in Patients with Heart Failure Receiving the Selective Cardiac Myosin Activator, CK-1827452" was displayed on Sunday, May 31, 2009 and was presented by Jonathan H. Goldman, MD, FACC, Chief Medical Officer, ICON Medical Imaging, Warrington, PA. This poster included the first public disclosure of analyses comparing the effect of CK-1827452 on ejection fraction calculated from two ventricular volumes assessed by the biplane Method of Discs and two hybrid methods that use a measurement of stroke volume based on Doppler interrogation of the left ventricular outflow tract and a single assessment of ventricular volume by the Method of Discs.