The purpose of this study is to assess the efficacy and safety of subcutaneous administration of a liquid formulation of C1 esterase inhibitor for the prevention of angioedema attacks in adolescent and adult subjects with hereditary angioedema.
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.