Dose-ranging Study of Oral PHA-022121 for Prophylaxis Against Angioedema Attacks in Patients With Hereditary Angioedema Type I or Type II

Inclusion Criteria: * Signed and dated informed consent form * Diagnosis of HAE type I or II * Documented history of at least 3 HAE attacks within the last 3 consecutive months prior to screening, or a minimum of 2 HAE attacks during the screening period * Reliable access and experience to use standard of care acute attack medications Exclusion Criteria: * Pregnancy or breast-feeding * Clinically significant abnormal electrocardiogram * Any other systemic disease or significant disease or disorder that would interfere with the patient's safety or ability to participate in the study * Use of C1-esterase inhibitor, oral kallikrein inhibitors, attenuated androgens, anti-fibrinolytics, or monoclonal HAE therapy within a defined period prior to enrolment * Abnormal hepatic function * Abnormal renal function * History of alcohol or drug abuse within defined period, or current evidence of substance dependence or abuse * Participation in any other investigational drug study within defined period