165 Early Versus Delayed Treatment of Swelling Attacks with Icatibant, a Bradykinin 2 Receptor Antagonist in Patients With Hereditary Angioedema due to C1-INH Deficiency

BACKGROUND: To compare the efficacy of icatibant in early versus late treated attacks of hereditary angioedema. METHODS: Thirty-one patients received 30 mg icatibant subcutaneously at various times for 121 swelling attacks. The time periods between onset of attacks and icatibant injection, icatibant injection and the first symptom relief, and icatibant injection and resolution of symptoms or, in some attacks, the start of a rebound attack were compared in 3 patient groups with different times to injection. RESULTS: Data are reported as mean ± SD. In 61 attacks treated at 2 or less hours after attack onset, the time to first relief was 1 ± 0.9 hours and the time to symptom resolution was 12.9 ± 11.5 hours. In 43 attacks treated at more than 2 to 5 hours, the time to first relief was 0.8 ± 1.2 hours and the time to resolution was 15.1 ± 15.3 hours. In 17 attacks treated later than 5 hours after attack onset, time to first relief was 0.6 ± 0.6 hours and time to resolution was 12.6 ± 10.3 hours. The percentages of attacks with first symptom relief within 30 minutes in the 3 groups were 59%, 70%, and 64.7%, respectively. There were no statistically significant differences between the groups. In a subgroup of 20 attacks treated within 1 hour after attack onset, the time to first relief was 0.6 ± 0.3 hours and the time to symptom resolution was 10 ± 12 hours. The only adverse events were injection site reactions that all resolved without intervention. CONCLUSIONS: Icatibant is equally effective in early and delayed treatment of acute HAE attacks, with an early onset of relief.