This is a Phase 3 multicenter trial in 2 parts to evaluate the long-term safety and efficacy of navenibart in adult and adolescent participants with hereditary angioedema (HAE) who participated in STAR-0215-301 (NCT06842823; ALPHA-ORBIT). Part 1 provides all participants with navenibart in a dose-controlled fashion; Part 2 introduces a personalized dosing option (PDO) for participants based on individual needs.

Inclusion Criteria:

1. Participants from STAR-0215-301 who met one of the following conditions:

1. Completed STAR-0215-301 through the Day 181 visit
2. Withdrew from STAR-0215-301 but met the following criteria:

i. Received 2 doses of IP ii. completed ≥ 2 months of trial follow-up after the second dose of IP iii. Met other eligibility criteria as assessed by Investigator

Exclusion Criteria:

1. Participation in an investigational clinical trial other than STAR-0215- 301 in the 30 days or any exposure to an investigational drug (other than navenibart in STAR-0215-301) within 5 half-lives before informed consent/assent
2. Any exposure to angiotensin-converting enzyme (ACE) inhibitors or any estrogen containing medications with systemic absorption (such as hormonal contraceptives or hormone replacement therapy) within 30 days before Screening.
3. Known sensitivity to the ingredients in the formulation of IP

All participants will knowingly receive navenibart, however participants, care providers, investigators, and outcome assessors will be blinded to their treatment arm for a duration specific to the individual.