A Phase 2 HAE Prophylaxis Study With Recombinant Human C1 Inhibitor

Inclusion Criteria: Patients fulfilling the following criteria at Screening are eligible for participation inthe study:

1. Age 13 years or older

2. Laboratory confirmed diagnosis of HAE

3. A history of frequent HAE attacks (at least 4 attacks per month across a minimum of 3consecutive months).

4. Female patients of childbearing potential who are sexually active must be willing touse an acceptable form of contraception.

5. Provided written informed consent (and written assent for minors)

6. Willingness and ability to comply with all protocol procedures

Exclusion Criteria: Patients who meet any of the following criteria at Screening are to be excluded from studyparticipation:

1. Patients with medical history of allergy to rabbits or rabbit-derived products (including rhC1INH)

2. Diagnosis of acquired angioedema (AAE)

3. Patients who are pregnant, or breastfeeding, or are currently intending to becomepregnant

4. Treatment with any investigational drug in the past 30 days

5. Patients with any condition or treatment that, in the opinion of the Investigator,might interfere with the evaluation of study objectives

6. Patients currently treated with angiotensin-converting enzyme (ACE) inhibitors