A Research Study Comparing Different Doses of CDR132L With Placebo on the Structure and Function of the Heart in People With Heart Failure With Preserved Ejection Fraction and Left Ventricular Hypertrophy

Inclusion Criteria:

• Age 40-84 years (both inclusive) at the time of signing the informed consent

• Documented symptomatic chronic heart failure (HF) diagnosed greater than or equal to (≥) 90 days prior to screening with at least weekly need for oral diuretictreatment, and New York Heart Association class II-III at screening

• Clinically stable and on optimised doses and unchanged drug classes ofguideline-directed HF therapy ≥45 days prior to randomisation

• Left ventricular ejection fraction ≥50% as assessed by echocardiography atscreening, measured by central laboratory

• Left ventricular hypertrophy assessed by echocardiography at screening measured bycentral laboratory with any of the following:

1. LVMi (greater than) >88 gram per square meter (g/m^2) for female participantsand >102 g/m^2 for male participants, using the truncated ellipsoid methodmeasured by central laboratory

2. LVMi >95 g/m2 for female participants and >115 g/m2 for male participants usingthe linear method (cube formula).

3. Interventricular septum diameter measured in diastole (IVSd) in the parasternallong axis view ≥1.1 cm for female participants and ≥1.2 cm for maleparticipants.

• Body mass index 18.5-40 kilogram per square meter (kg/m^2) (both inclusive) and bodyweight less than or equal to (≤) 140 kilogram (kg). Body mass index is calculated inthe electronic case report form based on height and body weight at the screeningvisit (visit 1)

• NT-proBNP ≥300 picograms per milliliter (pg/mL); NT-proBNP ≥600 pg/mL if atrialfibrillation/flutter is present at time of screening, measured by central laboratory

Exclusion Criteria:

• Estimated glomerular filtration rate lesser than (<) 30 milliliter per minute (mL/min)/1.73 square meter (m^2) at time of screening, measured by centrallaboratory

• Participants with an episode of acute kidney failure or acute kidney injury, at thediscretion of the investigator, within 90 days prior to randomisation

• Myocardial infarction, unstable angina pectoris or HF hospitalisation within 30 daysprior to screening

• Participants receiving intravenous HF medications within 45 days prior torandomisation

• Participants with CRT, pacemaker or implantable cardioverter-defibrillator

• Planned coronary revascularisation, pacemaker/cardioverter-defibrillator/CRTimplantation, ablation of cardiac arrythmias and valve repair/replacement at thetime of randomisation

• Stroke or transient ischemic attack within 12 months prior to randomisation

• Participants with potential disruption of the blood-brain barrier (e.g., multiplesclerosis), in the opinion of the investigator

• Known history of severe liver disease and/or alanine aminotransferase or aspartateaminotransferase >2.5 x upper limit of normal at screening, measured by centrallaboratory

• Known genetic (or highly suspected due to family history) cause of increased cardiacmass (including dilated cardiomyopathy, Fabry disease and likely pathogenic orpathogenic variants within hypertrophic cardiomyopathy [HCM]).

• Participants with suspected or diagnosed cardiac amyloidosis or sarcoidosis.