Hereditary angioedema: long-term treatment with one or more injections of C1 inhibitor concentrate per week.

BACKGROUND

Hereditary angioedema due to C1 inhibitor deficiency (HAE-C1-INH) is characterized by recurrent edema attacks in various organs. The objective of the present study was to assess the efficacy and safety of weekly long-term replacement treatment with one or more injections of plasma-derived C1-INH concentrate per week (WLTC) in patients with HAE-C1-INH.

METHODS

Nineteen patients with HAE-C1-INH underwent WLTC for 9 years on average. The benefits and risks were determined based on regular recording by the patients of the severity and number of attacks at the beginning and the end of the study.

RESULTS

All patients reported that all or most of their attacks were much less severe: the percentage of severe attacks was 93.3% without and 3.8% with treatment. In 8 of the 14 patients undergoing WLTC, the monthly number of attacks was lower at the end of the study than before the study, higher in 5 patients, and unchanged in 1 patient. The mean number of attacks per week in 6 patients (1 patient initially received weekly on-demand treatment for 2 years and then shifted to WLTC) with weekly on-demand treatment was 4.3 (SD 1.9) at the beginning and 8.0 (SD 3.1) at the end of the study.

CONCLUSIONS

HAE-C1-INH can be significantly improved by one or more injections of C1-INH concentrate per week. However, patients have to accept a large number of intravenous injections and, in some cases, an increase in disease activity.