Study of ARO-ENaC in Healthy Volunteers and in Patients With Cystic Fibrosis

Inclusion Criteria: * 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 * Normal electrocardiogram (ECG) at Screening * Non-smoking * Normal pulmonary function tests at Screening (NHVs only) * No abnormal finding of clinical relevance at Screening other than CF for CF patients * Confirmed diagnosis of CF based on source verifiable medical record (CF patients only) * All other treatments for CF have been stable for at least 2 months and patient is willing to continue this treatment regimen without change for duration of study (CF patients only) Exclusion Criteria: * Acute lower respiratory infection within 30 days of Screening (NHVs only) * History of asthma (specifically, those subjects at risk of bronchial hyperactivity), anaphylaxis or airway hyper-reactivity * Clinically significant history of hyperkalemia or presence of hyperkalemia at Screening * Clinically significant health concerns (other than CF in CF patients) * Human Immunodeficiency virus (HIV) infection, seropositive for Hepatitis B Virus (HBV), seropositive for Hepatitis C Virus (HCV) * Uncontrolled hypertension * Excessive use of alcohol within one month prior to Screening * Use of illicit drugs within 1 year prior to Screening * Use of an investigational agent or device within 30 days prior to dosing or current participation in an investigat…