Methods: Overall, this open-label, multicenter study evaluated subjects aged ≥1 year with a diagnosis of HAE; this subset analysis presents data on subjects aged <18 years. nf-C1-INH treatment was administered as 1000 U IV with a second 1000 U dose 60 minutes later, if needed. The presence of three consecutive assessments of improvement at 15-minute intervals within the 4-hr post-treatment period constituted relief. Safety was monitored through the recording of AEs and vital signs pre- and post-infusion. Viral safety labs and immunogenicity testing were also performed. Approval was obtained from WIRB and informed consent obtained from all subjects.
Results: Twenty-two pediatric subjects experienced a total of 121 HAE attacks, with 89% (108/121) achieving relief within 4 hours of nf-C1 INH administration. 91% (69/76) and 89% (39/44) of attacks in subjects aged 6-11 and aged 12-17 achieved relief within 4 hours of nf-C1INH administration, respectively. A two-year-old subject was given two 500 unit doses for a facial attack and reported symptom relief within 3 hours. Gastrointestinal attacks were the most common HAE manifestation. Of the 64 gastrointestinal attacks in 6-11 and 12-17 year olds, 97% (35/36) and 89% (25/28), respectively, experienced relief within 4 hours. No subjects with a laryngeal attack required intubation. There were no treatment emergent AEs reported as related to nf-C1 INH in these subjects. No subjects discontinued study drug due to AEs, had clinically relevant anti-C1 INH antibodies, or had evidence of transmission of HBV, HCV, or HIV.
Conclusion: Administration of 1000U of nf-C1 INH was well-tolerated and effective for the treatment of acute HAE attacks in children. In addition, intubation due to HAE was avoided in all subjects with a laryngeal attack.