This is a Phase 4, prospective, open-label trial to evaluate the safety and effectiveness of sebetralstat when used for STP for a qualifying procedures in patients 12 years of age or older with hereditary angioedema (HAE).

Inclusion Criteria:

1. Male or female patients ≥12 years of age at time of Screening
2. Confirmed diagnosis of HAE Type I or II based on patient report
3. Patient has a qualifying procedure that is scheduled or planned to be scheduled to occur within 8 weeks of Screening
4. Patient has access to a commercial available on-demand treatment for HAE
5. Female patients of childbearing potential, including post-menarchal adolescents, must meet contraception requirements per Section 11.3. (Note: male patients do not require contraception)
6. Patients must be able to swallow trial tablets whole
7. Patients, as assessed by the Investigator, must be able to appropriately receive and store IMP, and be able to read, understand, and complete the questionnaire
8. Investigator believes that the patient is willing and able to adhere to all protocol requirements through the duration of the trial
9. Patient provides informed consent or assent (when applicable). A parent or legally authorized representative (LAR) must also provide signed informed consent when required

Exclusion Criteria:

1. A clinically significant history of poor response to bradykinin receptor 2 blocker, C1-INH therapy, or plasma kallikrein inhibitor therapy for the management of HAE, in the opinion of the Investigator
2. Use of angiotensin-converting enzyme (ACE) inhibitors within 7 days prior to the Screening Visit
3. Any estrogen-containing medications with systemic absorption (such as oral contraceptives including ethinylestradiol or hormonal replacement therapy) within 7 days prior to the Screening Visit
4. Patients who are taking strong cytochrome P450 (CYP)3A4 inhibitors or inducers or moderate CYP3A4 inducers within 2 weeks of the procedure
5. Any clinically significant comorbidity or systemic dysfunction, which in the opinion of the Investigator, would jeopardize the safety of the patient by participating in the trial
6. History of substance abuse or dependence that would interfere with the completion of the trial, as determined by the Investigator
7. Known hypersensitivity to sebetralstat or to any of the excipients
8. Participation in any gene therapy treatment or trial for HAE
9. Any pregnant or breastfeeding patient

All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing but only after deidentification of individual patient data.