Developing Drugs for Heart Failure With Reduced Ejection Fraction: What Have We Learned From Clinical Trials?

Omecamtiv Mecarbil in the treatment of heart failure: the past, the present, and the future

Heart failure, a prevailing global health issue, imposes a substantial burden on both healthcare systems and patients worldwide. With an escalating prevalence of heart failure, prolonged survival rates, and an aging demographic, an increasing number of individuals are progressing to more advanced phases of this incapacitating ailment. Against this backdrop, the quest for pharmacological agents capable of addressing the diverse subtypes of heart failure becomes a paramount pursuit. From this viewpoint, the present article focuses on Omecamtiv Mecarbil (OM), an emerging chemical compound said to exert inotropic effects without altering calcium homeostasis. For the first time, as a review, the present article uniquely started from the very basic pathophysiology of heart failure, its classification, and the strategies underpinning drug design, to on-going debates of OM's underlying mechanism of action and the latest large-scale clinical trials. Furthermore, we not only saw the advantages of OM, but also exhaustively summarized the concerns in sense of its effects. These of no doubt make the present article the most systemic and informative one among the existing literature. Overall, by offering new mechanistic insights and therapeutic possibilities, OM has carved a significant niche in the treatment of heart failure, making it a compelling subject of study.

Differences in ejection fraction as inclusion criterion in randomized controlled trials among patients with heart failure with reduced ejection fraction: a systematic review

INTRODUCTION

Heart failure (HF) with reduced ejection fraction (HFrEF) has been defined by varying ejection fraction (EF) criteria in clinical trials, leading to differences in quantifying treatment effects.

AREAS COVERED

The definitions of HFrEF in randomized controlled trials from 2010 until 2020 were collected. The EF ranges were clustered into very low (<30%), low (30-39%) and mildly reduced (40-49%) stratified by intervention. Time series regression analysis was performed.A total of 3052 articles were screened and 706 were included. Interventions included were pharmacologic (37%), device therapy (10%) and 53% a combination of programs, procedural, and laboratory testing. By EF cutoffs, 41% of the studies utilized <40% while 26% used <35%. About 31% did not have a clearly defined EF. Between 2010-2020, studies with HFrEF ranges 30-39% have significantly decreased (p value<0.001 for trend) but those which included very low EF (<30%) and mildly reduced EF (40-49%) have remained the same. Expert opinion:EF definitions across clinical trials in HFrEF varied widely. Defining the specific target HF population phenotype when designing trials or in patient treatment is important as various beneficial effects of different heart failure treatment modalities can be modified or even attenuated across the spectrum of EF.

Nonpharmacologic Treatment for Heart Failure: A Review of Implantable Carotid Baroreceptor Stimulators As a Therapeutic Option

There has been significant interest in research for the development of device-based therapy as a treatment option of heart failure (HF), whether it is with reduced or preserved ejection fraction. This is due to the high morbidity and mortality rate in patients with HF despite recent advances in pharmacologic treatment. Following the success of cardiac resynchronization therapy, baroreceptor activation therapy has emerged as another novel device-based treatment for HF. The Barostim neo was developed by CVRx Minneapolis, MN for the treatment of mild to severe HF. The device works by electrically activating the baroreceptor reflex with the goal to restore the maladaptive autonomic imbalance that is seen in patients with HF. Preliminary clinical investigations have given promising results with an encouraging safety profile. Baroreceptor activation therapy as a treatment option is still investigational at this time; however, several trials in different patient populations have already shown benefit with a very good safety profile. In this review, we will summarize the current state of technology and the available literature of the use of baroreceptor activation therapy in patients with different comorbidities, with a focus on this device-based therapy in patients with HF.

Action of iron chelator on intramyocardial hemorrhage and cardiac remodeling following acute myocardial infarction

Intramyocardial hemorrhage is an independent predictor of adverse outcomes in ST-segment elevation myocardial infarction (STEMI). Iron deposition resulting from ischemia-reperfusion injury (I/R) is pro-inflammatory and has been associated with adverse remodeling. The role of iron chelation in hemorrhagic acute myocardial infarction (AMI) has never been explored. The purpose of this study was to investigate the cardioprotection offered by the iron-chelating agent deferiprone (DFP) in a porcine AMI model by evaluating hemorrhage neutralization and subsequent cardiac remodeling. Two groups of animals underwent a reperfused AMI procedure: control and DFP treated (N = 7 each). A comprehensive MRI examination was performed in healthy state and up to week 4 post-AMI, followed by histological assessment. Infarct size was not significantly different between the two groups; however, the DFP group demonstrated earlier resolution of hemorrhage (by T2* imaging) and edema (by T2 imaging). Additionally, ventricular enlargement and myocardial hypertrophy (wall thickness and mass) were significantly smaller with DFP, suggesting reduced adverse remodeling, compared to control. The histologic results were consistent with the MRI findings. To date, there is no effective targeted therapy for reperfusion hemorrhage. Our proof-of-concept study is the first to identify hemorrhage-derived iron as a therapeutic target in I/R and exploit the cardioprotective properties of an iron-chelating drug candidate in the setting of AMI. Iron chelation could potentially serve as an adjunctive therapy in hemorrhagic AMI.

DAPA-HF trial: dapagliflozin evolves from a glucose-lowering agent to a therapy for heart failure

Heart failure (HF) continues to be a major global health problem with a notable impact in terms of morbidity and mortality and so, in consequence, with a large unmet necessity for new therapies. The inhibition of sodium-glucose cotransporter 2 (SGLT2) causes glycosuria and natriuresis, leading to reductions in hyperglycemia (antidiabetic effect), body weight, and blood pressure. In this context, outcome trials have been shown to reduce hospitalizations for HF in patients with type 2 diabetes mellitus treated with SGLT2 inhibitors. The underlying protective cardiovascular (CV) mechanisms of these agents are complex, multifactorial, and not entirely understood as, in addition to a diuretic-like function, SGLT2 inhibitors may mitigate glycemic-related toxicity, promote ketogenesis, increase hematocrit, and exert antihypertrophic, antifibrotic, and antiremodeling properties. The DAPA-HF (Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure) trial enrolled 4744 patients with HF and reduced ejection fraction (EF) who were receiving excellent guideline-directed treatment before the addition of dapagliflozin (a SGLT2 inhibitor) or placebo. The DAPA-HF trial clearly showed that dapagliflozin was superior to placebo at preventing CV deaths and HF events. The relative and absolute risk reductions in death and hospitalizations were consistent across subgroups including patients with and without diabetes; so, in consequence, dapagliflozin represents the first in a new class of drug for HF with reduced EF. The recently published Dapagliflozin Effects on Biomarkers, Symptoms, and Functional Status in Patients With Heart Failure With Reduced Ejection Fraction (DEFINE-HF) trial is also described in this review as well as the thought-to-be mechanisms of action of SGLT2 inhibitors beyond their known glucose-lowering effects. There is a vast, ambitious, and promising ongoing clinical investigation program with dapagliflozin and other SGLT2 inhibitors, which may result in changes to the therapeutic approach to HF in a relatively short time.