Recombinant human C1 esterase inhibitor for acute hereditary angioedema attacks with upper airway involvement

Recombinant human C1 esterase inhibitor (rhC1-INH) is approved for treatment of hereditary angioedema (HAE) in adolescents and adults. HAE attacks that involve the upper airway can be life threatening, and data on the administration of rhC1-INH for these types of attacks are currently limited.

To evaluate the efficacy and safety of rhC1-INH for treatment of acute HAE attacks with upper airway involvement.

A pooled analysis of data from three clinical trials with open-label extensions examined rhC1-INH for treatment of acute HAE attacks with upper airway involvement. Patients with functional plasma C1 esterase inhibitor <50% of normal who had experienced an acute upper airway HAE attack and received rhC1-INH were identified retrospectively based on severity of breathing or swallowing symptoms. The primary end point was the time to beginning of relief (time at which the overall visual analog scale score [0-100 mm] decreased from baseline by ≥20 mm for two consecutive time points [persistence]).

Of 683 acute HAE attacks treated with rhC1-INH, data for 45 attacks with upper airway involvement were included. The median time to the beginning of symptom relief was 67 minutes (95% confidence interval, 60-120 minutes) and did not differ by attack number or by baseline breathing or swallowing symptom severity. Most attacks (91.1%) achieved the beginning of relief within 4 hours of rhC1-INH treatment. All attacks resolved without the need for any additional medication, and no patients required intubation or tracheostomy. Treatment with rhC1-INH was well tolerated, with no adverse events reported in more than one patient (except HAE reported as an adverse event [n = 2]).

This pooled analysis of clinical trial data supports the efficacy of rhC1-INH for treatment of acute HAE attacks with upper airway involvement.