Direct Myosin Activation by Omecamtiv Mecarbil for Heart Failure with Reduced Ejection Fraction

Background: Chronic heart failure with reduced ejection fraction impairs health-related quality of life (HRQL). Omecamtiv mecarbil (OM)—a novel activator of cardiac myosin—improves left ventricular systolic function and remodeling and reduces natriuretic peptides. We sought to evaluate the effect of OM on symptoms and HRQL in patients with chronic heart failure with reduced ejection fraction and elevated natriuretic peptides enrolled in the COSMIC-HF trial (Chronic Oral Study of Myosin Activation to Increase Contractility in Heart Failure). Methods: Patients (n=448) were randomized 1:1:1 to placebo, 25 mg of OM BID, or to pharmacokinetically guided dose titration (OM-PK) for 20 weeks. The Kansas City Cardiomyopathy Questionnaire was administered to assess HRQL at baseline, 16 weeks, and 20 weeks. The primary scores of interest were the Total Symptom Score, Physical Limitation Scale, and Clinical Summary Score. Results: Mean change in score from baseline to 20 weeks for the Total Symptom Score was 5.0 (95% CI, 1.8–8.1) for placebo, 6.6 (95% CI, 3.4–9.8) for OM 25 mg ( P =0.32 versus placebo), and 9.9 (95% CI, 6.7–13.0) for OM-PK ( P =0.03 versus placebo); for the Physical Limitation Scale, it was 3.1 for placebo (95% CI, −0.3 to 6.6), 6.0 (95% CI, 3.1–8.9) for OM 25 mg ( P =0.12), and 4.3 (95% CI, 0.7–7.9) for OM-PK ( P =0.42); for the Clinical Summary Score, it was 4.1 (95% CI, 1.4–6.9) for placebo, 6.3 (95% CI, 3.6–9.0) for OM 25 mg ( P =0.19), and 7.0 (95% CI, 4.1–10.0) for OM-PK ( P =0.14). Differences between OM and placebo were greater in patients who were more symptomatic at baseline. Conclusions: HRQL as measured by the Total Symptom Score improved in patients with heart failure with reduced ejection fraction assigned to the OM-PK group relative to placebo. Ongoing trials are prospectively testing whether OM improves symptoms and HRQL in heart failure with reduced ejection fraction. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01786512.

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P5440Systolic/diastolic effects of chronic treatment with omecamtiv mecarbil in minipigs with post-myocardial infarction Heart Failure with reduced Ejection Fraction (HFrEF)

European Heart Journal ◽

10.1093/eurheartj/ehz746.0396 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

D Caillaud ◽

X Baudot ◽

L Gouraud ◽

L Lucats ◽

M P Pruniaux ◽

...

Keyword(s):

Myocardial Infarction ◽

Heart Failure ◽

Ejection Fraction ◽

Healthy Volunteers ◽

Chronic Treatment ◽

Positive Inotropic Effect ◽

Post Myocardial Infarction ◽

Inotropic Effect ◽

Reduced Ejection Fraction ◽

Omecamtiv Mecarbil

Abstract Background Omecamtiv mecarbil (OM), a novel myosin ATPase activator, is currently developed for the treatment of Heart Failure with reduced Ejection Fraction (HFrEF). Phase I in healthy volunteers and patients showed that the positive inotropic effect of OM was associated with an impairment of diastolic function as assessed by change in E peak, e' wave and E/e' ratio. Purpose The diastolic impact of chronic treatment with OM has not been described yet. This study investigates the balance between positive inotropic effect and the diastolic impairment after chronic treatment with OM in a post-myocardial infarction (Post-MI) swine model of HFrEF. Methods HFrEF was induced in minipigs after myocardial infarction caused by a 150-min left anterior descending (LAD) artery occlusion performed under angiography. HFrEF minipigs were treated with OM at 3 mg/kg PO BID for 15 days (n=4), a dose known to increase systolic ejection time (SET) by ∼50 ms as achieved in healthy volunteers and patients at plasma levels between 200–300 ng/ml. Echocardiogram was performed before and after 15 days of treatment with OM. An additional echocardiogram was conducted 7 days after the last administration. Results One year after MI, minipigs displayed increased left ventricular end-diastolic volume index (LVEDVi 151±3.7ml/m2 vs 100±8.9ml/m2 before infarction) and decreased LVEF (42±2.5% vs 68±4.4% before infarction) associated with a pseudo-normal mitral pattern. A two-week treatment with OM increased SET by 64ms (p<0.0001 vs before treatment) and EF to 49±3.8% (p=0.07 vs before treatment) as well as it improved SVi by 13%. This inotropic effect was associated with a decrease of mitral E peak (p=0.01 vs before treatment) and e' waves, and with the prolongation of deceleration time (p<0.05 vs before treatment). OM treatment was associated with marked reduction of LVEDVi to 117±13.2ml/m2 (p<0.05 vs before treatment) concomitant with a ∼20% increase in diastolic septum and posterior wall thicknesses. None of these systolic or diastolic effects remained 7 days post OM treatment completion. Conclusion Similarly to clinical description, OM treatment increased LVEF and SVi principally through extension of SET. It provides positive inotropic effects associated with diastolic impairment resulting in impaired ventricular filling as assessed by LVEDVi decrease and the thickening of ventricular wall in diastole. Whether this profile will allow a beneficial reverse remodeling, needs to be investigated in a longer chronic study. Acknowledgement/Funding Sanofi sponsored study

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