A Study to Learn More About How Safe Finerenone is, When it is Taken for a Longer Time With Standard Treatment, in Children and Young Adults With Heart Failure and Left Ventricular Systolic Dysfunction

• Finerenone (Kerendia, BAY94-8862) (Drug): Finerenone in different doses, treatment duration will be 270±7 days.

Primary outcomes

• Number of participants with treatment-emergent adverse events (TEAEs) [From the start of study intervention to last study intervention (up to 277 days) + 3 days]: TEAEs will be mapped to Medical Dictionary for Regulatory Activities (MedDRA) terms.
• Change in serum potassium levels [From baseline to Day 270±7]
• Change in systolic blood pressure (SBP) [From baseline to Day 270±7]
• Change in estimated glomerular filtration rate (eGFR) [From baseline to Day 270±7]

Secondary outcomes

• Change in NT-proBNP levels [From baseline to Day 270±7]
• Change in left ventricular systolic function [From baseline to Day 270±7]: Change measured by echocardiogram (%) from baseline to Day 270±7
• Maximum observed finerenone concentration in plasma after multiple doses (Cmax, md) [Pre-dose, post-dose (1.5-5 hours after intake of intervention), up to Day 270±7]
• Area under the curve for finerenone concentration in plasma after multiple doses (AUCτ,md) [Pre-dose, post-dose (1.5-5 hours after intake of intervention), up to Day 270±7]
• Taste and Texture Questionnaire of the pediatric formulation [On Day 30±3 and Day 270±7]: For newborns and infants <6 months of age, the taste and texture of the pediatric formulation will be evaluated using the Taste and Texture Questionnaire, completed by the caregiver, or health care professional. Results for the Taste and Texture Questionnaire from newborns and infants <6 months of age who receive the pediatric formulation will be summarized descriptively.

Sex: All, ages: any to 18 Years

Inclusion Criteria:

* For participants rolling over from randomized controlled trial (RCT): Prior participation in the finerenone Phase 3 study FIORE (21466) and not permanently discontinued from the study intervention prior to the end of treatment (EoT) visit in FIORE.
* For newly enrolled infants <6 months of age: Left ventricular systolic dysfunction (LVSD) with left ventricular ejection fraction (LVEF) ≤ 50% at screening assessed by echocardiography.
* For newly enrolled infants <6 months of age: Elevated NT-pro BNP levels (> 500 ng/L) at screening.
* For newly enrolled infants <6 months of age: Heart failure (HF) etiologies include congenital heart defects (CHD) with biventricular physiology and systemic LV; idiopathic cardiomyopathy (CM); familial/inherited and/or genetic CM; history of myocarditis (diagnosis of an acute episode at least 3 months prior to treatment assignment); neuromuscular disorder; inborn error of metabolism; mitochondrial disorder; acquired (chemotherapy, iatrogenic, infection, rheumatic, or nutritional); ischemic (e.g., Kawasaki disease and postoperative HF); LV noncompaction.
* For newly enrolled infants <6 months of age: Receiving standard of care (SoC) treatment for heart failure according to local guidelines or investigator´s discretion (on a stable regimen for 30 days before baseline).
* Newly enrolled newborns and infants < 6 months of age must have a body weight of ≥3 kg at Visit 1.

Exclusion Criteria:

* For participants rolling over from randomized controlled trial (RCT): To roll-over to FIORELLO, all participants: Potassium (K+) >5.5 mmol/L based on local laboratory results. After unblinding:

  * For participants who received finerenone in FIORE: K+ >5.5 mmol/ L
  * For participants who received placebo in FIORE: K+ >5.0 mmol/L for children ≥2 years of age, and >5.3 mmol/L for children <2 years of age (if eGFR is <60 mL/min/1.73m² for participants <2 years of age, the serum potassium threshold of >5.0 mmol/L will be used for exclusion)
* For newly enrolled newborns and infants < 6 months of age: Potassium ≥ 5.3 mmol/l (if eGFR is <60 mL/min/1.73m², the serum potassium threshold of >5.0 mmol/L will be used for exclusion).
* For participants rolling over from RCT: Severe renal dysfunction with estimated glomerular filtration rate (eGFR) < 30 ml/min/1.73m² based on local laboratory results at FIORELLO Visit 1.
* For newly enrolled infants < 6 months of age: Severe renal dysfunction with eGFR < 30 ml/min/1.73m2 at screening or Visit 1.
* Treatment with a mineralocorticoid receptor antagonist, other than the study intervention, (e.g., spironolactone, eplerenone) within 30 days of Visit 1.
* Requirement of any intravenous (IV) vasoactive agents; mechanical ventilation; mechanical circulatory support; sustained or symptomatic arrhythmias not controlled by drug or device therapy within 30 days prior to study treatment.

32 more sites not listed.