Model-based approaches for ivabradine development in paediatric population, part II: PK and PK/PD assessment

[Research progress in the application of ivabradine in children with cardiovascular diseases]

Ivabradine, as a specific If current inhibitor, has been widely used in the treatment of chronic heart failure in adults due to its ability to reduce heart rate without affecting myocardial contractility and blood pressure. It has also shown good effects in various types of tachyarrhythmias. However, the application of ivabradine in pediatric cardiovascular diseases still faces many limitations. This article reviews the current research progress on the use of ivabradine in treating pediatric cardiovascular diseases both domestically and internationally, aiming to provide guidance for pediatric cardiologists. Citation:Chinese Journal of Contemporary Pediatrics, 2024, 26(7): 782-788.

Pharmacology of Ivabradine and the Effect on Chronic Heart Failure

Chronic Heart Failure (CHF) is a complex clinical syndrome with a high incidence worldwide. Although various types of pharmacological and device therapies are available for CHF, the prognosis is not ideal, for which, the control of increased Heart Rate (HR) is critical. Recently, a bradycardic agent, ivabradine, is found to reduce HR by inhibiting the funny current (If). The underlying mechanism states that ivabradine can enter the Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels and bind to the intracellular side, subsequently inhibiting the If. This phenomenon can prolong the slow spontaneous phase in the diastolic depolarization, and thus, reduce HR. The clinical trials demonstrated the significant effects of the drug on reducing HR and improving the symptoms of CHF with fewer adverse effects. This review primarily introduces the chemical features and pharmacological characteristics of ivabradine and the mechanism of treating CHF. Also, some expected therapeutic effects on different diseases were also concluded. However, ivabradine, as a typical If channel inhibitor, necessitates additional research to verify its pharmacological functions.

Ivabradine in Children With Dilated Cardiomyopathy and Symptomatic Chronic Heart Failure

BACKGROUND

Heart rate reduction as a therapeutic target has been investigated in adults with heart failure (HF). Ivabradine has shown promising efficacy, but has not been evaluated in children. Currently, treatment recommendations for chronic pediatric HF are based mainly on chronic HF guidelines for adults.

OBJECTIVES

The authors explored the dose-response relationship of ivabradine in children with dilated cardiomyopathy and symptomatic chronic HF. The primary endpoint was ≥20% reduction in heart rate from baseline without inducing bradycardia or symptoms.

METHODS

This was a randomized, double-blind, placebo-controlled, phase II/III study with 12 months of follow-up. Children (n = 116) receiving stable HF therapy were randomized to either ivabradine or placebo. After an initial titration period, the dose was adjusted to attain the primary endpoint. Left ventricular function (echocardiography), clinical status (New York Heart Association functional class or Ross class), N-terminal pro-B-type natriuretic peptide, and quality of life (QOL) were assessed.

RESULTS

The primary endpoint was reached by 51 of 73 children taking ivabradine (70%) versus 5 of 41 taking placebo (12%) at varying doses (odds ratio: 17.24; p < 0.0001). Between baseline and 12 months, there was a greater increase in left ventricular ejection fraction in patients taking ivabradine than placebo (13.5% vs. 6.9%; p = 0.024). New York Heart Association functional class or Ross class improved more with ivabradine at 12 months than placebo (38% vs. 25%; p = 0.24). There was a trend toward improvement in QOL for ivabradine versus placebo (p = 0.053). N-terminal pro-B-type natriuretic peptide levels decreased similarly in both groups. Adverse events were reported at similar frequencies for ivabradine and placebo.

CONCLUSIONS

Ivabradine safely reduced the resting heart rate of children with chronic HF and dilated cardiomyopathy. Ivabradine's effect on heart rate was variable, highlighting the importance of dose titration. Ivabradine treatment improved left ventricular ejection fraction, and clinical status and QOL showed favorable trends. (Determination of the efficacious and safe dose of ivabradine in paediatric patients with dilated cardiomyopathy and symptomatic chronic heart failure from ages 6 months to 18 years; ISRCTN60567801).