A Study of ARC-AAT in Healthy Volunteer Subjects and Patients With Alpha-1 Antitrypsin Deficiency (AATD)

Inclusion Criteria: (Part A - Healthy Volunteers) * Male or female healthy volunteers 18-50 years of age * Written informed consent * Body mass index between 18.0 and 28.0 kg/m2 * 12-lead electrocardiogram (ECG) at Screening and pre-dose assessment with no clinically significant abnormalities * Non-pregnant/non-nursing females * Non-smoker for at least one year with current non-smoking status confirmed by urine cotinine * Normal lung function (or not clinically significant per investigator assessment) based on spirometry and diffusion capacity of lung for carbon monoxide (DLCO) according to American Thoracic Society (ATS) - European Respiratory Society (ERS) criteria * Highly effective, double barrier contraception (both male and female partners) during the study and for 3 months following the dose of ARC-AAT * Willing and able to comply with all study assessments and adhere to protocol schedule * Suitable venous access for blood sampling * No abnormal finding of clinical relevance at screening * Normal AAT level (Part B-Patients) - As for Part A with the following exceptions: * Male or female patients 18-70 years of age * Confirmed diagnosis of homozygous alpha 1-protease inhibitor deficiency (PiZZ genotype) not receiving alpha-1 antitrypsin augmentation therapy for more than 4 weeks * BMI between 18.0 and 35.0 kg/m2 * Non-smoker for at least three years with current non-smoking status confirmed by urine cotinine Exclusion Criteria: (Part A-Healthy Volunteers) * Current regular smoker of cigarettes or cigars or was a regular smoker over the past 1 year * Recent (within last 6 weeks) transfusion of fresh frozen plasma, platelets, or packed red blood cells, or anticipated need for transfusion during study * Acute signs of hepatitis/other infection within 4 weeks of screening and/or baseline * Concurrent anticoagulants * Use of dietary and/or herbal supplements that can interfere with liver metabolism within 7 days of screening * Use of any drugs known to induce or inhibit hepatic drug metabolism within 14 days prior to study treatment * Depot injection/implant of any drug other than birth control within 3 months prior to study treatment * Diagnosis of diabetes mellitus or history of glucose intolerance * History of poorly controlled autoimmune disease or any history of autoimmune hepatitis * Human immunodeficiency virus (HIV) infection * Seropositive for hepatitis B virus (HBV) or hepatitis C virus (HCV), and/or history of delta virus hepatitis * Uncontrolled hypertension (blood pressure \> 150/100 mmHg) * History of cardiac rhythm disturbances * Family history of congenital long QT syndrome or unexplained sudden cardiac death * Symptomatic heart failure (per New York Heart Association \[NYHA\] guidelines) * Unstable angina, myocardial infarction, severe cardiovascular disease, transient ischemic attack (TIA) or cerebrovascular accident (CVA) within past 6 months * History of malignancy within last 5 years except adequately treated basal cell carcinoma, squamous cell skin cancer, superficial bladder tumors, or in situ cervical cancer. * History of major surgery within 3 months of screening * Regular use of alcohol within 1 month prior to screening (i.e., more than fourteen units of alcohol per week) * Evidence of acute inflammation, sepsis or hemolysis or clinical evidence of lower respiratory tract infection * Diagnosis of significant psychiatric disorder * Use of illicit drugs (such as cocaine, phencyclidine \[PCP\] and crack) within 1 year prior to screening or positive urine drug screen * History of allergy or hypersensitivity reaction to bee venom * Use of an investigational agent or device within 30 days prior to dosing or current participation in an investigational study * Clinically significant history/presence of any gastrointestinal pathology, unresolved gastrointestinal symptoms, liver or kidney disease * Other conditions known to interfere with the absorption, distribution, metabolism, or excretion of drugs * Any clinically significant history/presence of poorly controlled neurological, endocrinal, cardiovascular, pulmonary, hematological, immunologic, psychiatric, metabolic or other uncontrolled systemic disease * Blood donation (500 mL) within 7 days prior to study treatment * History of fever within 2 weeks of screening * Concomitant medical/psychiatric condition or social situation that would affect compliance or result in additional safety risk * Excessive exercise/physical activity within 3 days of screening or enrollment or planned during the study * History of thromboembolic disease, stroke within 6 months of baseline, and/or concurrent anticoagulant medication(s) (Part B-Patients) - As for Part A with the following exceptions: * History of major surgery within 2 months of Screening * Forced expiratory volume at one second (FEV1) at baseline \< 60% * AATD patients with liver elastography score \> 11 at Screening