Safety, Tolerability and Pharmacodynamic Effect of Fazirsiran (TAK-999, ARO-AAT)

Inclusion Criteria: * Diagnosis of AATD * Liver biopsy at Screening indicating liver fibrosis (score less than F4); a patient with no fibrosis may participate based on a previous biopsy conducted within one year * Women of childbearing 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 1 year * No abnormal finding of clinical relevance at Screening Exclusion Criteria: * Clinically significant health concerns other than AATD * Previous diagnosis or diagnosis at Screening of definitive liver cirrhosis * Previous lung or liver transplant due to AATD * 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 involving therapeutic intervention * Use of illicit drugs within 1 year prior to Screening NOTE: additional inclusion/exclusion criteria may apply, per protocol