a research study to look at how a new medicine called nnc6019-0001 works and how safe it is for people who have heart disease due to transthyretin (ttr) amyloidosis

Conditions: Transthyretin Amyloid Cardiomyopathy (ATTR CM)

Summary: this study is testing a potential new medicine, nnc6019-0001, for people who have a heart disease due to ttr amyloidosis.the study will look at if this medicine can reduce the symptoms of a heart disease due to ttr amyloidosis, such as heart failure. participants will either get nnc6019-0001 (apotential new medicine) or placebo (a medicine which has no effect on the body). which treatment participants get is decided by chance. the chance of getting nnc6019-0001 is two times higher than getting placebo. nnc6019-0001 is not yet approved in any country or region in the world. it is a new medicine that doctors cannot prescribe yet. participants will get an infusion of the study medicine 13 times, once every 4 weeks. the study will last for about 64 weeks after the first dose of medicine. participants cannot participate in this study if they have a heart disease other than a heart disease due to ttr amyloidosis.


Eligibility criteria:
inclusion criteria: * male or female. * age greater than or equal to (\>=) 18 to less than (\<) 85 years at the time of signing informed consent. * have an established diagnosis of transthyretin amyloid cardiomyopathy (attr cm) with either wild-type transhyretin (ttr) or hereditary transthyretin (ttr) genotype as per local standards. * expected to be on stable doses of cardiovascular medical therapy 6 weeks prior to the randomisation visit. * known end-diastolic interventricular septal wall thickness greater than or equal to (\>=) 12 millimeters (mm). * presently classified as new york heart association (nyha) class ii-iii. * n-terminal-pro brain natriuretic peptide (nt-probnp) concentration greater than or equal to (\>=) 650 picograms per milliliter (pg/ml) in sinus cardiac rhythm and greater than (\>) 1000 pg/ml in atrial fibrillation at screening. * completed greater than or equal to (\>=) 150 meters to less than or equal to (\<=) 450 meters on the 6-minute walk test (mwt) at screening. * estimated glomerular filtration rate (egfr) greater than or equal to (\>=) 25 milliliter per minute per 1.73 meter square (ml/min/1.73 m\^2) at screening. exclusion criteria: * cardiomyopathy not primarily caused by transthyretin amyloid cardiomyopathy transthyretin amyloid cardiomyopathy (attr cm), for example, cardiomyopathy due to hypertension, valvular heart disease, or ischemic heart disease. * a prior solid organ transplant. * planned solid organ transplant during the study. * presence or history of malignant neoplasm (other than basal or squamous cell skin cancer, insitu carcinomas of the cervix, or in-situ/high grade prostatic intraepithelial neoplasia (pin) or low-grade prostate cancer) within 5 years before screening. * current treatment with calcium channel blockers with conduction system effects (example \[e.g.\], verapamil, diltiazem). the use of dihydropyridine calcium channel blockers is allowed. the use of digoxin will only be allowed if required for management of atrial fibrillation with rapid ventricular response. * acute coronary syndrome, unstable angina, stroke, transient ischemic attack (tia), coronary revascularization, cardiac valve repair, or major surgery within 3 months of screening. * body weight \>120 kilogram (kg) (264.6 pounds \[lb\]) at screening. * history of contrast allergy or adverse reactions to gadolinium-containing agents.