This study will evaluate the efficacy and safety of ADX-324 in participants with Type 1 or Type 2 hereditary angioedema. The study will also evaluate safety, pharmacokinetics (PK), pharmacodynamics (PD), and health-related quality of life measures.

Key Inclusion Criteria:

• Age ≥18 years at the time of signing informed consent.
• Have a documented diagnosis of HAE-1/HAE-2 (Type I or II)
• Experience ≥1 Investigator-confirmed HAE attack in the first 4 weeks of Screening or ≥2 Investigator-confirmed HAE attacks in 8 weeks of Screening
• Able to use at least one acute therapy to treat HAE attacks (such as a plasma-derived or recombinant C1-INH concentrate or a BK2-receptor antagonist)

Key Exclusion Criteria:

• Concurrent diagnosis of another form of recurrent angioedema (such as acquired angioedema, HAE with normal C1-INH (previously known as HAE Type III), idiopathic angioedema, or recurrent angioedema associated with urticaria).

• Any clinically significant renal disease

• Any clinically significant hepatic disease

• Have used any of the following for long-term prevention of HAE attacks:

  1. C1-INH agent (CINRYZE, HAEGARDA, RUCONEST) within 2 weeks prior to Screening.
  2. Berotralstat (ORLADEYO) within 3 weeks prior to Screening.
  3. Lanadelumab (TAKHZYRO) within 8 weeks prior to the Screening.
  4. Androgen use within 12 weeks prior to Screening.

• Received prior treatment with any RNA/DNA-based therapy for HAE or intolerant to any prior RNA/DNA-based therapy for any condition, excluding vaccines.

Double blinded