The patient joins the study after providing signed informed consent. If applicable, a parent or legally authorized representative must also provide consent.

The patient must have a confirmed diagnosis of hereditary angioedema (HAE) type I or II and have experienced at least two documented HAE attacks within three months prior to enrollment.

The patient must be 12 years of age or older and able to swallow tablets whole.

The patient receives KVD900, an oral plasma kallikrein inhibitor, in the form of a film-coated tablet.

The medication is taken on-demand to treat angioedema attacks. The specific dosage and frequency are determined by the study protocol and the patient’s needs.

The patient is monitored for any adverse events (AEs) and serious adverse events (SAEs) that may occur within two days of taking the medication.

Regular assessments are conducted to check for normal or abnormal laboratory results and vital signs at each scheduled visit.

The time to the beginning of symptom relief is evaluated, defined as at least ‘a little better’ within 12 hours of the initial dose.

The time to the resolution of the HAE attack is also assessed, defined as ‘none’ within 24 hours of the initial dose.

The study is estimated to continue until March 9, 2026.

The patient’s participation involves adhering to all protocol requirements and completing an electronic diary (eDiary) to document their experiences and any symptoms.