PHARMACOKINETICS OF RECOMBINANT HUMAN C1 ESTERASE INHIBITOR FOR TREATMENT OF HEREDITARY ANGIOEDEMA ATTACKS IN CHILDREN

Introduction Recombinant human C1 inhibitor (rhC1-INH) is indicated for the acute treatment of hereditary angioedema (HAE) attacks in adults/adolescents. Methods An open-label, phase 2 study evaluated rhC1-INH as acute treatment in children. Eligible HAE attacks were treated with rhC1-INH 50 IU/kg body weight (maximum, 4200 IU). A second dose was permitted at the investigator's discretion, based on clinical response. Blood samples for pharmacokinetic (PK) analyses were collected before treatment, at 5-minutes post-treatment, and 2-4 hours post-treatment for the first HAE attack. Results Twenty children (aged 5-14 years) were treated with rhC1-INH for 73 attacks. Seventy of the attacks (95.9%) were treated with a single dose. Baseline functional C1-INH concentrations were below the lower limit of quantification (70% of normal (lower limit of normal range). The most common adverse events reported in the 20 children were nasopharyngitis (n=3; 15.0%) and vomiting (n=3; 15.0%). Conclusions Data support that single administration of a weight-based rhC1-INH dose yields functional C1-INH concentrations in the normal range for children aged ≥5 years.