Amgen and Cytokinetics announce the first presentation of data from Phase 2 ATOMIC-AHF study of Omecamtiv Mecarbil

Amgen (NASDAQ: AMGN) and Cytokinetics Incorporated (NASDAQ: CYTK) today announced the first presentation of data from the ATOMIC-AHF (Acute Treatment with Omecamtiv Mecarbil to Increase Contractility in Acute Heart Failure) study at the ESC Congress 2013, organized by the European Society of Cardiology, in Amsterdam. ATOMIC-AHF was a randomized, double-blind, placebo-controlled Phase 2 study that enrolled 613 patients hospitalized with acute heart failure (AHF) treated for 48 hours with omecamtiv mecarbil or placebo and designed to evaluate the safety, pharmacokinetics, pharmacodynamics, and potential efficacy of an intravenous formulation of omecamtiv mecarbil in patients with AHF. The study did not meet its primary endpoint of dyspnea (shortness of breath) response as measured by the 7-point Likert scale through 48 hours (p=0.33) but showed favorable dose and concentration-related trends on dyspnea response.

ATOMIC-AHF enrolled three, sequential, dose escalation cohorts of patients treated for 48 hours with omecamtiv mecarbil or placebo. The primary efficacy endpoint in ATOMIC-AHF was dyspnea symptom response. Secondary endpoints included other clinical and pharmacodynamic (echocardiographic) effects including death or worsening heart failure within seven days. The omecamtiv mecarbil treatment groups were not statistically different in their 7-point Likert scale dyspnea symptom response rates compared to the pooled placebo group (p=0.33); therefore, the primary endpoint was not met. Omecamtiv mecarbil demonstrated favorable dose- and concentration-related trends (nominal p=0.025 and nominal p=0.007, respectively) on dyspnea response. Improvement in dyspnea was observed in the highest omecamtiv mecarbil dose group when compared against its paired placebo group in the third cohort (dyspnea symptom response in 51 percent of subjects on omecamtiv mecarbil versus 37 percent on placebo, nominal p=0.03). The incidence of worsening heart failure within seven days of initiating treatment was 17 percent in the pooled placebo group and was 13 percent, 8 percent and 9 percent on omecamtiv mecarbil in the first, second and third cohorts, respectively. Systolic ejection time, the echocardiographic signature of omecamtiv mecarbil, increased in a concentration-dependent manner.

Rates of adverse events (AEs), serious AEs, adjudicated deaths and hospitalizations were similar between omecamtiv mecarbil and placebo groups. There were seven post-randomization myocardial infarctions in the omecamtiv mecarbil treated groups compared with three in the placebo groups (2.3 percent vs. 1.0 percent, respectively). However, there was no relationship between the maximum increase from the baseline troponin (a biomarker specific for cardiac muscle damage) and increasing plasma concentrations of omecamtiv mecarbil. Omecamtiv mecarbil was not associated with an increased incidence of tachyarrhythmias nor were heart rate or blood pressure adversely affected.

“Although ATOMIC-AHF did not achieve its primary efficacy endpoint, we are encouraged by the data from this study,” said Sean E. Harper, M.D., executive vice president of Research and Development at Amgen. “Omecamtiv mecarbil is a unique investigational therapy for patients with acute and chronic heart failure. We look forward to the data from the COSMIC-HF study, which together with the data from ATOMIC-AHF will inform our decision on whether to progress omecamtiv mecarbil into Phase 3 clinical trials.”

“We are pleased with the results from ATOMIC-AHF,” stated Robert I. Blum, President and CEO at Cytokinetics. “This novel mechanism drug candidate has consistently been associated with dose-related and plasma concentration-related pharmacodynamic and other effects in a robust program of Phase 1 and Phase 2 clinical trials. We look forward to results from COSMIC-HF and the potential progression of omecamtiv mecarbil in development.”

ATOMIC-AHF and COSMIC-HF

ATOMIC-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.