The purpose of this study is to determine the safety, tolerability, pharmacokinetics and pharmacodynamics of ALN-TTRSC02 in healthy subjects.

Inclusion Criteria:

• Male and female subjects, age 18 to 65 years, inclusive.
• Body mass index (BMI) ≥18.0 kg/m2 and ≤30 kg/m2 assessed at Screening.
• No clinically significant health concerns, as determined by medical history and physical examination, in the opinion of the Investigator.
• Women of child bearing potential must have a negative pregnancy test, cannot be breastfeeding, and must be willing to use contraception, willing and able to comply with the study requirements and to provide written informed consent.
• For Japanese cohorts, subjects of Japanese descent are defined as people carrying a Japanese passport, descendants of 4 Japanese grandparents, and have not been outside Japan for more than 5 years.

Exclusion Criteria:

• Clinically relevant history or presence of respiratory, gastrointestinal, renal, cardiovascular, hepatic, hematological, lymphatic, neurological, psychiatric, musculoskeletal, genitourinary, immunological, and other inflammatory diseases, or dermatological or connective tissue diseases or disorders.
• Active serious mental illness or psychiatric disorder.
• Clinically significant ECG abnormalities. Abnormal for AST/ALT and any other clinical safety laboratory result considered clinically significant.
• Known history of allergic reaction to an oligonucleotide or GalNAc.
• History of intolerance to subcutaneous injection.