This is a research study to test an experimental study drug (belcesiran, also known as
DCR-A1AT). This drug is being tested to see if it helps people with a rare condition known as
Alpha-1 Antitrypsin Deficiency, or A1ATD. Prior to initiation of this study belcesiran had
not yet been tested in humans. All study participants will be randomly assigned to either
receive the study drug or a placebo. This will allow for the sponsor to compare the effects
of the study drug with that of the placebo. A placebo looks like the study drug but does not
contain any of the study drug.
The main purpose of the first part of the study is to evaluate the safety profile of the
study drug in people who do not have A1ATD. This part of the study will also help find the
dose of the study drug that has an acceptable safety profile for testing.