Methods: This open-label, multicenter study evaluated subjects aged ≥1 year with a diagnosis of HAE who experienced ≥1 HAE attack per month or had any history of laryngeal edema. nf-C1 INH was administered as prophylactic therapy at a dose of 1000 U IV every 3 to 7 days. Efficacy was based on the frequency of all HAE attacks experienced. Subjects were instructed to record all attacks on a daily basis. Safety was monitored through the recording of AEs and vital signs pre- and post-infusion. Virology and immunogenicity testing were also performed. Approval was obtained from WIRB and informed consent obtained from all subjects.
Results: Prior to enrollment, the 23 children in this study reported a mean HAE attack rate of 4.4 ± 5.7 per month. During nf-C1 INH therapy, the mean monthly attack rate was 0.7 ± 0.98 in those aged 2-5 years old (n=2), 0.4 ± 0.45 in those aged 6-11 years old (n=9), and 0.7 ± 0.90 in those aged 12-17 years old (n=12). Overall, 87% of the 23 children experienced ≤1 HAE attack per month with nf-C1 INH prophylaxis. The only treatment emergent AEs considered to be related was headache, nausea, and infusion-site erythema; none of which were severe. There were no severe hypersensitivity reactions, including anaphylaxis. There were no subjects who discontinued study drug due to AEs, had detectable anti-C1 INH antibodies, or had evidence of transmission of HBV, HCV, or HIV.
Conclusion: nf-C1 INH therapy reduced HAE attacks to ≤1 per month in most of the pediatric subjects in this study. nf-C1 INH was shown to be efficacious and well tolerated when administered for prophylaxis of HAE attacks in pediatric subjects.