APOLLO-B: A Study to Evaluate Patisiran in Participants With Transthyretin Amyloidosis With Cardiomyopathy (ATTR Amyloidosis With Cardiomyopathy)

Inclusion Criteria:

• Documented diagnosis of ATTR amyloidosis with cardiomyopathy, classified as eitherhereditary ATTR amyloidosis with cardiomyopathy or wild-type ATTR amyloidosis withcardiomyopathy

• Medical history of heart failure with at least 1 prior hospitalization for heartfailure, or current clinical evidence (signs and symptoms of heart failure)

• Clinically stable with no cardiovascular related hospitalizations within 6 weeks ofstudy start

• Has never taken tafamidis before (tafamidis naïve) or currently on tafamidis for ≥6months with evidence of disease progression while on tafamidis treatment

• Able to complete ≥150 m on the 6-minute walk test

• Screening N-terminal pro B-type natriuretic peptide (NT-proBNP), a blood marker ofheart failure severity, >300 ng/L and <8500 ng/L; in participants with permanent orpersistent atrial fibrillation, screening NT-proBNP> 600 ng/L and <8500 ng/L

Exclusion Criteria:

• Known primary amyloidosis (AL) or leptomeningeal amyloidosis.

• Received prior TTR lowering treatment

• New York Heart Association heart failure classification of III and at high risk

• New York Heart Association heart failure classification of IV

• Neuropathy requiring cane or stick to walk, or is wheelchair bound

• Estimated glomerular filtration rate (eGFR) <30 mL/min/1.73m^2

• Abnormal liver function

• Has hepatitis B, hepatitis C or human immunodeficiency virus (HIV) infection

• Has non-amyloid disease that significantly affects ability to walk (e.g., severechronic obstructive pulmonary disease, severe arthritis, or peripheral vasculardisease affecting ambulation)

• Prior or planned heart, liver, or other organ transplant

• Other cardiomyopathy not related to ATTR amyloidosis