A Phase 2 in Adult Subjects With Hereditary Angioedema

Inclusion Criteria:

• Must have given written informed consent and be able to comply with all studyrequirements.

• 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 aninvestigator 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 surgicallysterile

Exclusion Criteria:

• Any clinically significant medical or psychiatric condition or medical history that,in the opinion of the Investigator, makes the subject unsuitable for participationin the study

• Any concomitant diagnosis of another form of chronic angioedema, such as acquiredangioedema, HAE with normal C1-INH, idiopathic angioedema, or recurrent angioedemaassociated with urticaria

• History or presence of carcinoma within 5 years prior to screening, except for basalor squamous cell carcinoma of the skin or carcinoma in situ of the cervix that hasbeen successfully treated.

• Have undergone major surgery within 3 months prior to screening.

• History of clinically significant arterial or venous thrombosis, or currentclinically 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 12months if multiple doses prior to screening.

• Exposure to another investigational drug or biological agent within 30 days orwithin at least 5 half-lives prior to screening.

• With ANY of the abnormalities in clinical laboratory tests at screening and run-inperiod

• Clinically significant findings on 12-lead electrocardiogram that would place thepatient at risk or interfere with participation in the study at screening.

• Positive for Human immunodeficiency virus (HIV), HBsAg, Hepatitis C or syphilisinfection

• Active infection requiring systemic antiviral or antimicrobial therapy that will notbe completed prior to dosing.