Is finerenone effective and safe compared to placebo in reducing the occurrence of total (first and subsequent) heart failure (HF) events and cardiovascular (CV) death among patients hospitalized with acute decompensated Heart Failure with mild-range Ejection Fraction/Heart Failure with Preserved Ejection Fraction (HFmrEF/HFpEF)?

Study sites: The National Hospital of Sri Lanka, Colombo North Teaching Hospital, Sri Jayewardenepura General Hospital, Kandy National Hospital, District General Hospital Polonnaruwa, Colombo South Teaching Hospital, Jaffna Teaching Hospital, Negombo District General Hospital, General Sir John Kotelawala Defence University

Randomisation: Participants will be randomly assigned to treatment groups based on a computer-generated randomization schedule prepared before the study by or under the supervision of the sponsor statistician or delegate. Randomization will be balanced by using randomly permuted blocks for each site and stratified by country.

Intervention: Patients will be randomly allocated (1:1) to receive one finerenone or matching placebo tablet orally each day. The dose will be adjusted based on the patient’s kidney function and serum/plasma potassium. The starting dose of finerenone or placebo will depend on the local laboratory eGFR value at baseline. The investigator will titrate the dose of study intervention once the participant has been on a stable dose for 30±7 days. Participants who do not tolerate their starting dose of 20 mg may be down titrated at any point during the study, including between scheduled visits if required for safety reasons. Up titration of dose may be performed from Day 30 onward at any scheduled or unscheduled contact. eGFR and serum/plasma potassium will be checked 28±7 days after dose adjustment and at any other time deemed appropriate by the investigator. Patients will be instructed to take one tablet of study medication at approximately the same time each day, with a glass of water with or without food. Tablets containing 10 mg and 20 mg finerenone will differ in size from 40 mg finerenone tablets, but will be identical in appearance (size, shape, color) to matching placebo tablets. The packaging and labelling will be designed to maintain the blinding of the investigator’s team and the participants. The placebo tablet is active-free tablet and contains lactose.

• Males and females age >=18 years • Current hospitalization or recently discharged with the primary diagnosis of heart failure • Heart failure signs and symptoms at the time of hospital admission • Imaging evidence of mildly reduced or preserved left ventricular ejection fraction (EF) (40% or higher) • Elevated N-terminal pro B-type natriuretic peptide (NTproBNP) >=1000 pg/mL or B-type natriuretic peptide (BNP) >=250 pg/mL for patients without atrial fibrillation (AF); or elevated NTproBNP >=2000 pg/mL or BNP >=500 pg/mL for patients with AF

• Treatment with a mineralocorticoid receptor antagonist (MRA) • Documented prior history of severe hyperkalemia in the setting of MRA use • Estimated glomerular filtration rate (eGFR) <25 mL/min/1.73m² or serum/plasma potassium >5.0 mmol/L at screening • Acute myocardial infarction, coronary revascularization, valve replacement/repair, or implantation of a cardiac resynchronization therapy device within 30 days • Hemodynamically significant (severe) uncorrected primary cardiac valvular disease • Cardiomyopathy due to known acute inflammatory heart, infiltrative diseases, accumulation diseases, muscular dystrophies, cardiomyopathy with reversible causes, known hypertrophic obstructive cardiomyopathy, complex congenital heart disease, or known pericardial constriction • Probable alternative cause of participant's heart failure symptoms • Concomitant systemic therapy with potent cytochrome P450 isoenzyme 3A4 (CYP3A4) inhibitors or moderate CYP3A4 inducers, or potent CYP3A4 inducers