A Phase 2 in Adult Subjects With Hereditary Angioedema

Inclusion Criteria: * Must have given written informed consent and be able to comply with all study requirements. * Males or females 18 to 70 years of age at the time of informed consent. * Documented diagnosis of HAE-1/HAE-2. * At least 2 HAE attacks within the 8-week run-in period, as confirmed by an investigator based on the protocol-specified definition * Access to and ability to use ≥ 1 acute medication(s) * Female subjects must be non-pregnant;non-lactating, and either surgically sterile * Male subjects with WOCBP partners, dual contraception is required if no surgically sterile Exclusion Criteria: * Any clinically significant medical or psychiatric condition or medical history that, in the opinion of the Investigator, makes the subject unsuitable for participation in the study * Any concomitant diagnosis of another form of chronic angioedema, such as acquired angioedema, HAE with normal C1-INH, idiopathic angioedema, or recurrent angioedema associated with urticaria * History or presence of carcinoma within 5 years prior to screening, except for basal or squamous cell carcinoma of the skin or carcinoma in situ of the cervix that has been successfully treated. * Have undergone major surgery within 3 months prior to screening. * History of clinically significant arterial or venous thrombosis, or current clinically significant prothrombotic or bleeding risk * History of allergic reaction to an oligonucleotide or N-acetylgalactosamine * Prior treatment with any oligonucleotides within 6 months if single dose or 12 months if multiple doses prior to screening. * Exposure to another investigational drug or biological agent within 30 days or within at least 5 half-lives prior to screening. * With ANY of the abnormalities in clinical laboratory tests at screening and run-in period * Clinically significant findings on 12-lead electrocardiogram that would place the patient at risk or interfere with participation in the study at screening. * Positive for Human immunodeficiency virus (HIV), HBsAg, Hepatitis C or syphilis infection * Active infection requiring systemic antiviral or antimicrobial therapy that will not be completed prior to dosing.