Background: Administration of C1-inhibitor concentrate is effective for prophylaxis and treatment of severe angioedema attacks caused by Cl-inhibitor deficiency. The concentrate should be administered intravenously and hence needs to be administered by health care professionals, which might cause considerable delay in treatment and inconvenience for patients.
Objective: The aim of this study was to investigate the feasibility, efficacy, and safety of on-demand and prophylactic self-administration of C1-inhibitor concentrate in patients with frequent attacks of angioedema.
Methods: Patients with hereditary or acquired Cl-inhibitor deficiency who had very frequent angioedema attacks were trained to self-administer Cl-inhibitor concentrate. The study consisted of 31 patients using on-demand treatment and 12 patients using prophylaxis with C1-inhibitor concentrate. Mean follow-up was 3.5 years.
Results: All patients were capable of self-administering the concentrate, with technical failure rates of self-injection being less than 2%. Times between the onset of the attack and the initiation of relief or complete resolution of symptoms in the on-demand group were significantly shortened (2.2 hours and 7.9 hours, respectively) compared with the situation before the start of self-administration. In the prophylaxis group self-administration of Cl-inhibitor concentrate decreased the angioedema attack rate from 4.0 to 0.3 attacks per month.
Conclusion: Intravenous self-administration of Cl-inhibitor concentrate is a feasible and safe option and results in more rapid and more effective treatment or prevention of severe angioedema attacks in patients with Cl-inhibitor deficiency. Clinical implications: Self-administration of C1-inhibitor concentrate could be a valuable and convenient treatment modality to prevent or treat angioedema attacks in patients with C1-inhibitor deficiency.