An Open-label Extension Trial to Evaluate the Long-term Safety of KVD900 (Sebetralstat) for On-Demand Treatment of Angioedema Attacks in Adolescent and Adult Patients With Hereditary Angioedema (HAE)

Patients may roll over from KVD900-301.

Inclusion criteria

• Confirmed diagnosis of HAE type I or II at any time in the medical history
• Patient has had at least 2 documented HAE attacks within 3 months prior to the Enrollment Visit.
• If a patient is receiving long-term prophylactic treatment with one of the protocol-allowed therapies, they must have been on a stable dose and regimen for at least 3 months prior to the Enrollment Visit (except for danazol, which requires a stable dose and regimen for at least 6 months prior to the Enrollment Visit).
• Male or female patients 12 years of age and older.
• Patients must meet the contraception requirements.
• Patients must be able to swallow trial tablets whole.
• Patients, as assessed by the Investigator, must be able to appropriately receive and store IMP, and be able to read, understand, and complete the eDiary.
• Investigator believes that the patient is willing and able to adhere to all protocol requirements.
• Patient provides signed informed consent or assent (when applicable). A parent or legally authorized representative (LAR) must also provide signed informed consent when required.

Exclusion criteria

• Discontinued from the KVD900-301 trial for reasons of noncompliance, withdrawal of consent, or safety.
• Presence of any safety concerns that would preclude participation in the open-label trial as determined by the investigator.
• Any concomitant diagnosis of another form of chronic angioedema, such as acquired C1 inhibitor deficiency, HAE with normal C1-INH (previously known as HAE type III), idiopathic angioedema, or angioedema associated with urticaria.
• A clinically significant history of poor response to bradykinin receptor 2 (BR2) blocker, C1-INH therapy, or plasma kallikrein inhibitor therapy for the management of HAE, in the opinion of the Investigator.
• Use of attenuated androgens other than danazol (e.g., stanozolol, oxandrolone, methyltestosterone, testosterone), or anti-fibrinolytics (e.g., tranexamicacid) within 28 days prior to the Enrollment Visit.
• Use of Angiotensin-converting enzyme (ACE) inhibitors within 7 days prior to the Enrollment Visit.
• Any estrogen-containing medications with systemic absorption (such as oral contraceptives including ethinylestradiol or hormonal replacement therapy) within 7 days prior to the Enrollment Visit.
• Inadequate organ function, including but not limited to:

• Alanine aminotransferase (ALT) >2x Upper Limit Normal (ULN)
• Aspartate aminotransferase (AST) >2x ULN
• Bilirubin direct >1.25x ULN
• International Normalized Ratio (INR) >1.2
• Clinically significant hepatic impairment defined as a Child-Pugh B or C
• 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.
• History of substance abuse or dependence that would interfere with the completion of the trial, as determined by the Investigator.
• Known hypersensitivity to KVD900 or to any of the excipients.
• Participation in any gene therapy treatment or trial for HAE.
• Participation in any interventional investigational clinical trial, including an investigational COVID-19 vaccine trial, within 4 weeks of the last dosing of investigational drug prior to the Enrollment Visit.
• Any pregnant or breastfeeding patient.