Self-administration of C1-inhibitor concentrate in patients with hereditary or acquired angioedema caused by C1-inhibitor deficiency

Background

Administration of C1-inhibitor concentrate is effective for prophylaxis and treatment of severe angioedema attacks caused by C1-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 C1-inhibitor deficiency who had very frequent angioedema attacks were trained to self-administer C1-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 C1-inhibitor concentrate decreased the angioedema attack rate from 4.0 to 0.3 attacks per month.

Conclusion

Intravenous self-administration of C1-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 C1-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.

Key words: C1-inhibitor deficiency, C1-inhibitor concentrate, hereditary angioedema, acquired angioedema