The purpose of this study is to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of single- and multiple-ascending doses of ARO-AAT in healthy adult volunteers.

Inclusion Criteria:

• Women of child bearing potential must have a negative pregnancy test, cannot be breastfeeding, and must be willing to use contraception
• Willing to provide written informed consent and to comply with study requirements
• Non-smoker for at least one year
• Normal lung function
• No abnormal finding of clinical relevance at Screening
• Normal AAT level at Screening visit

Exclusion Criteria:

• Clinically significant health concerns
• Regular use of alcohol within one month prior to Screening
• Use of an investigational agent or device within 30 days prior to dosing or current participation in an investigational study
• Recent use of illicit drugs
• Use of any drugs or dietary/herbal supplements know to interfere with liver metabolism

NOTE: additional inclusion/exclusion criteria may apply, per protocol