86 The Efficacy and Safety of Human Plasma-derived C1-Inhibitor Concentrate Administered for the Treatment of Attacks in Pediatric Patients with Hereditary Angioedema Due to C1-Inhibitor Deficiency

Abstract

BackgroundHereditary angioedema due to C1-inhibitor deficiency (HAE-C1-INH) is a life-threatening, rare disease characterized by recurrent edematous attacks. In 50% of cases, the initial onset of symptoms occurs between 5 and 11 years of age. There are limited data on the emergency treatment of acute episodes in pediatric patients. Our aim was to analyze the efficacy and safety of human plasma-derived C1-INH concentrate in our pediatric patient population with HAE-C1-INH.Methods50 pediatric patients (23 boys, 27 girls; 45 HAE type I, 5 HAE type II patients) were enrolled. The follow-up period began at the time of diagnosis and ended when the patient turned 18 years old. The indications for the use of C1-INH concentrate were upper airway oedema of any severity; moderate-to-severe abdominal edema; edema of face, neck, or lips and severe edema of the extremities and trunk. Clinical and laboratory data were entered into the Hungarian HAE Registry.Results152 attacks out of 1392 experienced by 42 patients were treated with C1-INH concentrate (28% of attacks at home and 72% at the clinic). The distribution of C1-INH-treated attacks by location was as follows: 38% subcutaneous, 32% abdominal, 30% upper airway. In all locations, the clinical symptoms were consistently relieved by 500 IU C1-INH concentrate. An additional 500 IU dose of C1-INH concentrate was required in 4 cases only. The symptoms improved within 15 to 60 minutes of drug administration. Time to complete resolution was 24 to 48 hours in subcutaneous edema, 12 to 24 hours in abdominal attacks, and less than 12 hours when the edema involved the upper airways. No progression or recurrence of the attack was observed. Repeated administration did not reduce therapeutic efficacy of the drug. Adverse events did not occur. Transmission of viral infections (HIV, HBV, HBC, Parvo virus B19) was not detected. Comparing the first and last year of follow-up, anti-C1-INH antibodies (IgA, IgG, IgM types) did not show any relationship with the administration of C1-INH concentrate.ConclusionsOur prospective study demonstrated that the administration of C1-INH concentrate is highly effective and safe for the treatment of edematous attacks – regardless their location – in pediatric patients with HAE-C1-INH.