Study to Evaluate the Clinical Efficacy and Safety of Subcutaneously Administered C1 Esterase Inhibitor for the Prevention of Angioedema Attacks in Adolescents and Adults With Hereditary Angioedema

You may be eligible if

• The maximum duration of participation is approximately 9 months. Patients will complete a screening period of up to 21 days. Following screening, eligible patients will be randomly assigned to 1 of 3 treatment sequences. Each patient will undergo 2 14-week treatment periods for a total of 28 weeks (Treatment Period 1 and Treatment Period 2). After completing the 2 treatment periods, patients will enter a 1-month follow-up period.