This is a Phase 3 multicenter, randomized, double-blind, placebo-controlled clinical trial evaluating the safety and efficacy of subcutaneous administration of navenibart in adult and adolescent participants with type 1 or type 2 hereditary angioedema (HAE). The goal of this clinical trial is to evaluate the efficacy and safety of navenibart compared to placebo in preventing HAE attacks in participants with HAE.

Inclusion Criteria:

• Documented diagnosis of HAE (Type 1 or 2). The following must be met:

  1. Documented clinical history consistent with HAE
  2. Lab findings consistent with HAE Type 1 or 2

• Experienced at least 2 HAE attacks during the Run-In period, as confirmed by an investigator based on meeting the protocol-specified definition of an HAE attack.

Exclusion Criteria:

• Any concomitant diagnosis of another form of chronic angioedema, such as acquired C1 inhibitor deficiency, HAE with normal C1-INH (also known as HAE type 3), idiopathic angioedema, or angioedema associated with urticaria.

• Use of therapies prescribed for the prevention of HAE attacks may not be used during the trial or within the below time frames prior to the Run-In Period (adult participants may be on these medications at the time of the Screening Visit, but will need to washout prior to entering the Run-In Period).

  1. Tranexamic acid, oral danazol, oral stanazolol, and oral oxandrolone within 3 days prior to Run-In
  2. Plasma-derived C1INH for LTP within 14 days prior to Run-In
  3. Berotralstat within 21 days prior to Run-In
  4. Lanadelumab within 70 days prior to Run-In
  5. Garadacimab within 90 days prior to Run-In