PK Subtrial in Adolescent Patients With HAE Type I or II Participating in the KVD900-302 Trial

Inclusion Criteria: * Male or female adolescent patient 12 to 17 years of age at the time of enrollment and during sample collection in this PK subtrial. * Patient is currently participating in KVD900-302. * Patient must provide signed informed consent or assent (when applicable), and a legally authorized representative (LAR) must also provide signed informed consent when applicable. * Patient and LAR are willing and able to provide samples per the requirements of the protocol, including willingness to complete forms and the electronic Diary, obtain and return samples in a timely manner, and obtain samples while within the required age limit. Exclusion Criteria: * Patient has a history of any bleeding disorder or currently taking any anti-coagulant or anti-platelet agent.