Efficacy, pharmacokinetics, and safety of icatibant for the treatment of Japanese patients with an acute attack of hereditary angioedema: A phase 3 open-label study

Abstract

Background: Hereditary angioedema (HAE) is a genetic disease characterized by recurrent swelling episodes affecting the skin, gastrointestinal mucosa, and upper respiratory tract. Methods: A phase 3, single-arm, open-label study was performed to evaluate a selective bradykinin B2 receptor antagonist, icatibant, for the treatment of acute attacks in Japanese patients with HAE Type I or II. After the onset of an acute attack, icatibant 30 mg was administered by the patient or a healthcare professional via subcutaneous injection in the abdomen. Results: Eight patients who had an attack affecting the skin (n = 4), abdomen (n = 3), or larynx (n = 1) were treated with icatibant (3 of the injections were self-administered). The median time to onset of symptom relief was 1.75 h (95% confidence interval, 1.00–2.50), and all patients had symptom relief within 5 h after administration. The time to maximum plasma concentration of icatibant was 1.79 h, and the maximum plasma concentration was 405 ng/ml. Seven patients experienced an injection site reaction, and 3 patients had adverse events (2 patients had a worsening or repeat HAE attack 29.0 and 18.3 h after icatibant administration, respectively, and 1 had headache). Conclusions: Although the number of patients is small, the efficacy and tolerability of icatibant for acute attacks were demonstrated in Japanese patients with HAE, regardless of self-administration or administration by healthcare professional. Keywords: Bradykinin B2 receptor antagonist, Hereditary angioedema Types I and II, Icatibant, Japan, Phase 3 clinical trial