C1 Esterase Inhibitor (C1INH-nf) for the Prevention of Acute Hereditary Angioedema (HAE) Attacks

Inclusion Criteria: * Documented HAE * Normal C1q level * Relatively frequent angioedema attacks (at least 2 per month on average) Exclusion Criteria: * Low C1q level * B-cell malignancy * Presence of anti-C1INH autoantibody * History of allergic reaction to C1INH or other blood products * Narcotic addiction * Current participation in any other investigational drug study or within the past 30 days * Participation in a C1 esterase inhibitor trial, or received blood or a blood product in the past 90 days * Pregnancy or lactation * Any clinically significant medical condition, such as renal failure, that in the opinion of the investigator would interfere with the subject's ability to participate in the study