MAGNITUDE is a research study for people with a heart condition called transthyretin amyloidosis with cardiomyopathy (ATTR-CM). In this study, doctors will give a special medicine called NTLA-2001 or a placebo (a fake treatment) to see if it helps people with this condition. A placebo is used to compare and see if the real medicine works better. This study will include about 765 people from different countries.

To participate, you need:

• A confirmed diagnosis of ATTR-CM
• A history of heart failure
• Blood tests showing a specific heart marker is high

Important points:

• The study involves one infusion (IV treatment) and follows up over time.
• Participants must be stable on heart failure treatments before starting.
• Conditions like severe heart failure, certain infections, or recent cancer can exclude you.

Before joining, consider if you can commit to the study's duration and requirements, including taking vitamin A supplements. This study aims to check the safety and effectiveness of NTLA-2001, which could help improve care for ATTR-CM patients.