Inclusion Criteria:  Are males and in agreement to follow contraceptive requirements, or women of non-child-bearing potential Have a body mass index (BMI) of < 40.0 kilograms per square meter (kg/m²) Have chronic stable heart failure (New York Heart Association (NYHA) classification II and III) on guideline directed heart failure therapy for at least 6 months prior to enrolment Have not changed optimal guideline directed therapy in the last 1 month prior to screening, If treated with oral diuretics, dose must be stable for at least 2 weeks prior to screening Have Left Ventricular Ejection Fraction (LVEF) < 40% Have a record of N-terminal pro b-type natriuretic peptide (NT-ProBNP) ≥ 300 picograms per millilitre (pg/mL)  Exclusion Criteria:  Have myocardial infarction, coronary artery bypass graft surgery or other major cardiovascular surgery, stroke in the last 90 days prior to screening Have acute decompensated heart failure requiring IV diuretics within 12 weeks prior to screening Have cardiac amyloidosis, accumulation diseases (e.g., haemochromatosis, Fabry disease), muscular dystrophies, hypertrophic cardiomyopathy, pericardial constriction, or complex congenital heart disease. Have any moderate-to-severe stenosis of the mitral and/or aortic valve or moderate-to severe or greater mitral and/or aortic regurgitation. Have a history or presence of hepatic, pancreatic, or biliary tract disorders Have a history of malignancy or active malignancy at screening. Have not had age-appropriate cancer screening as recommended by the American Cancer Society and per medical judgment