Background: Hereditary angioedema (HAE) is characterized by paroxysmal edema of the skin, gastrointestinal mucosa, and upper respiratory tract.
Purpose: This study investigated icatibant, a selective bradykinin B2 receptor antagonist, as treatment for Japanese patients with an acute HAE attack.
Methods: This was an open-label, single-arm, Phase 3 study of Japanese adults with HAE type I or II. Icatibant (30 mg) was administered (by a healthcare professional [HCP] or self-administered) as a subcutaneous injection in the abdomen.
Results: Eight patients (4 cutaneous, 3 abdominal, 1 laryngeal) were treated with icatibant (all single injection; 3 self-administered, 5 HCP-administered). The median time to onset of symptom relief was 1.75 hours (95% confidence interval, 1.00 to 2.50); all patients had onset of relief within 5 hours. The estimated time to maximum icatibant concentration in the circulation was 1.79 hours and the maximum concentration was 405 ng/mL. There were 3 patients who experienced 3 adverse events (2 HAE attacks and 1 headache); 7 patients experienced an injection site reaction.
Conclusion: Although our study was limited by the small number of patients, we found that icatibant was an effective and well-tolerated treatment for Japanese patients with acute HAE attacks, regardless of whether it was administered by a HCP or self-administered.
Keywords: Japan; bradykinin B2 receptor antagonist; hereditary angioedema Types I and II; icatibant; phase III clinical trial.