A Study to Evaluate ALN-6400 in Healthy Volunteers and Patients With Hereditary Hemorrhagic Telangiectasia (HHT)

Inclusion Criteria -

Part A:

• Is a healthy adult volunteer

Part B:

• Is an adult patient with a clinical diagnosis of HHT

Exclusion Criteria -

Part A:

• Has alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > upper limit of normal (ULN)

• Has known human immunodeficiency virus (HIV) infection; or known current or chronic hepatitis C virus or hepatitis B virus infection

• Has an estimated glomerular filtration (eGFR) of <90 mL/min/1.73m^2 at screening

Part B:

• Has ALT or AST >2×ULN

• Has total bilirubin >1.5×ULN

• Has eGFR of <30 mL/min/1.73m^2 at screening

Parts A and B:

• Is not willing to comply with the contraceptive requirements during the study period

Note: other protocol defined inclusion / exclusion criteria apply