Pharmacokinetic Drug-Drug Interaction Study of Omecamtiv Mecarbil With Amiodarone and Digoxin in Healthy Subjects

Mechanism-based inactivation of cytochromes P450: implications in drug interactions and pharmacotherapy

Cytochrome P40 (CYP) enzymes dominate the metabolism of numerous endogenous and xenobiotic substances. While it is commonly believed that CYP-catalysed reactions result in the detoxication of foreign substances, these reactions can also yield reactive intermediates that can bind to cellular macromolecules to cause cytotoxicity or irreversibly inactivate CYPs that create them.Mechanism-based inactivation (MBI) produces either irreversible or quasi-irreversible inactivation and is commonly caused by CYP metabolic bioactivation to an electrophilic reactive intermediate. Many drugs that have been known to cause MBI in CYPs have been discovered as perpetrators in drug-drug interactions throughout the last 20-30 years.This review will highlight the key findings from the recent literature about the mechanisms of CYP enzyme inhibition, with a focus on the broad mechanistic elements of MBI for widely used drugs linked to the phenomenon. There will also be a brief discussion of the clinical or pharmacokinetic consequences of CYP inactivation with regard to drug interaction and toxicity risk.Gaining knowledge about the selective inactivation of CYPs by common therapeutic drugs helps with the assessment of factors that affect the systemic clearance of co-administered drugs and improves comprehension of anticipated interactions with other drugs or xenobiotics.

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.

Novel Treatments of Hypertrophic Cardiomyopathy in GDMT for Heart Failure: A State-of-art Review

This state-of-the-art review discuss the available evidence on the use of novel treatments of hypertrophic cardiomyopathy such as omecamtiv mecarbil, EMD-57033, levosimendan, pimobendan, and mavacamten for the treatment of heart failure (HF) in the context of guideline-directed medical therapy (GDMT). The paper provides a detailed overview of these agents' mechanisms of action, potential benefits and limitations, and their effects on clinical outcomes. The review also evaluates the efficacy of the novel treatments in comparison to traditional medications such as digoxin. Finally, we seek to provide insight and guidance to clinicians and researchers in the management of HF patients.

Small molecule drugs to improve sarcomere function in those with acquired and inherited myopathies

Muscle weakness is a hallmark of inherited or acquired myopathies. It is a major cause of functional impairment and can advance to life-threatening respiratory insufficiency. During the past decade, several small-molecule drugs that improve the contractility of skeletal muscle fibers have been developed. In this review, we provide an overview of the available literature and the mechanisms of action of small-molecule drugs that modulate the contractility of sarcomeres, the smallest contractile units in striated muscle, by acting on myosin and troponin. We also discuss their use in the treatment of skeletal myopathies. The first of three classes of drugs discussed here increase contractility by decreasing the dissociation rate of calcium from troponin and thereby sensitizing the muscle to calcium. The second two classes of drugs directly act on myosin and stimulate or inhibit the kinetics of myosin-actin interactions, which may be useful in patients with muscle weakness or stiffness.NEW & NOTEWORTHY During the past decade, several small molecule drugs that improve the contractility of skeletal muscle fibers have been developed. In this review, we provide an overview of the available literature and the mechanisms of action of small molecule drugs that modulate the contractility of sarcomeres, the smallest contractile units in striated muscle, by acting on myosin and troponin.

Influence of atrial fibrillation on efficacy and safety of omecamtiv mecarbil in heart failure: the GALACTIC-HF trial

AIMS

In GALACTIC-HF, the cardiac myosin activator omecamtiv mecarbil compared with placebo reduced the risk of heart failure events or cardiovascular death in patients with heart failure with reduced ejection fraction. We explored the influence of atrial fibrillation or flutter (AFF) on the effectiveness of omecamtiv mecarbil.

METHODS AND RESULTS

GALACTIC-HF enrolled patients with New York Heart Association (NYHA) Class II-IV heart failure, left ventricular ejection fraction ≤35%, and elevated natriuretic peptides. We assessed whether the presence or absence of AFF, a pre-specified subgroup, modified the treatment effect for the primary and secondary outcomes, and additionally explored effect modification in patients who were or were not receiving digoxin. Patients with AFF (n = 2245, 27%) were older, more likely to be randomized as an inpatient, less likely to have a history of ischaemic aetiology or myocardial infarction, had a worse NYHA class, worse quality of life, lower estimated glomerular filtration rate, and higher N-terminal pro-B-type natriuretic peptide. The treatment effect of omecamtiv mecarbil was modified by baseline AFF (interaction P = 0.012), with patients without AFF at baseline deriving greater benefit. The worsening of the treatment effect by baseline AFF was significantly more pronounced in digoxin users than in non-users (interaction P = 0.007); there was minimal evidence of effect modification in those patients not using digoxin (P = 0.47) or in digoxin users not in AFF.

CONCLUSION

Patients in AFF at baseline were less likely to benefit from omecamtiv mecarbil than patients without AFF, although the attenuation of the treatment effect was disproportionally concentrated in patients with AFF who were also receiving digoxin.Clinical Trial Registration: NCT02929329.