Hereditary angioedema with normal C1 inhibitor in a French cohort: Clinical characteristics and response to treatment with icatibant

Introduction: The clinical characteristics and icatibant-treatment outcomes of patients with hereditary angioedema with normal C1 inhibitor (HAE-nC1 INH) are limited. Methods: We retrospectively analyzed data from French HAE patients enrolled in the Icatibant Outcome Survey registry (from July 2009 to September 2013) to compare disease characteristics and the effectiveness and safety of acute icatibant-treated angioedema attacks in patients with HAE-nC1 INH, HAE with C1 INH deficiency (type I), or dysfunction (type II). Results: One center in Grenoble contributed 22 patients with HAE-nC1 INH and a family history of HAE while 15 centers across France contributed 153 patients with HAE type I and seven patients with HAE type II. Patients with HAE-nC1 INH compared to HAE type I, respectively, were more likely to be female (88.1% vs. 63.4%), older at median age of disease onset (21 years vs. 15 years), and have a greater rate of abdominal (80% vs. 61%) and laryngeal (23% vs. 14%) attacks. Icatibant was effective in both groups though the median time to resolution of attack was significantly longer in the HAE-nC1 INH group (20.0 h, 37 attacks) versus the HAE type I group (14.0 h, 67 attacks). Icatibant was self-administered for 96.1% of attacks in patients with HAE-nC1 INH and 75.8% in patients with HAE type I. No serious adverse side effects related to icatibant were reported. Conclusions: These data help further define the disease characteristics of HAE-nC1 INH in the French population and extend the limited data reporting the safe and effective use of icatibant in acute treatment of angioedema in French patients diagnosed with HAE-nC1 INH.