Efficacy and Safety Study of DX-88 to Treat Acute Attacks of Hereditary Angioedema (HAE)

Inclusion Criteria: * Age 10 and older * Documented diagnosis of HAE, Type I or II * Executed informed consent * Presentation for treatment within 8 hours of patient recognition of moderate to severe HAE attack Exclusion Criteria: * Receipt of investigational drug or device, other than DX-88, within 30 days of treatment * Receipt of non-investigational C1-INH (C1 esterase inhibitor) within 7 days of treatment * Diagnostic of acquired angioedema, estrogen-dependent angioedema or drug induced angioedema * Pregnancy or breastfeeding * Patients who have received DX-88 within 7 days of presentation for dosing in the Double-blind Phase