The purpose of this study is to determine the pharmacokinetics, pharmacodynamics and exploratory clinical activity of ALN-TTRSC (revusiran) in Patients with Transthyretin (TTR) Cardiac Amyloidosis.

Inclusion Criteria:

• TTR cardiac amyloidosis;
• Women of child-bearing potential (WOCBP) must have a negative pregnancy test, cannot be breast feeding, and must be willing to use 2 highly effective methods of contraception;
• Male subjects agree to use appropriate contraception;
• Adequate blood counts, liver, renal and heart function;
• Adequate Karnofsky performance status;
• Adequate New York Heart Association (NYHA) Classification Score;
• Clinically stable on heart medications;
• Adequate 6-minute walk test;
• Willing to give written informed consent and are willing to comply with the study requirements.

Exclusion Criteria:

• Known human immunodeficiency virus (HIV) positive status or known or suspected systemic bacterial, viral, parasitic, or fungal infection;
• Subjects with a history of multiple drug allergies or intolerance to SC injection;
• Received an investigational agent other than tafamidis, diflunisal, doxycycline or tauroursodeoxycholic acid, or an investigational device within 30 days prior to first dose of study;
• Uncontrolled hypertension, ischemic heart disease or cardiac arrhythmia;
• Untreated hypo- or hyperthyroidism;
• Prior major organ transplant;
• Considered unfit for the study by the Principal Investigator.