Background: Attacks of hereditary angioedema (HAE) are unpredictable and, if affecting the upper airway, can be lethal. Icatibant is used for physician- or patient self-administered symptomatic treatment of HAE attacks in adults. Its mode of action includes disruption of the bradykinin pathway via blockade of the bradykinin B(2) receptor. Early treatment is believed to shorten attack duration and prevent severe outcomes; however, evidence to support these benefits is lacking.
Objective: To examine the impact of timing of icatibant administration on the duration and resolution of HAE type I and II attacks.
Methods: The Icatibant Outcome Survey is an international, prospective, observational study for patients treated with icatibant. Data on timings and outcomes of icatibant treatment for HAE attacks were collected between July 2009-February 2012. A mixed-model of repeated measures was performed for 426 attacks in 136 HAE type I and II patients.
Results: Attack duration was significantly shorter in patients treated <1 hour of attack onset compared with those treated ≥ 1 hour (6.1 hours versus 16.8 hours [p<0.001]). Similar significant effects were observed for <2 hours versus ≥ 2 hours (7.2 hours versus 20.2 hours [p<0.001]) and <5 hours versus ≥ 5 hours (8.0 hours versus 23.5 hours [p<0.001]). Treatment within 1 hour of attack onset also significantly reduced time to attack resolution (5.8 hours versus 8.8 hours [p<0.05]). Self-administrators were more likely to treat early and experience shorter attacks than those treated by a healthcare professional.
Conclusion: Early blockade of the bradykinin B(2) receptor with icatibant, particularly within the first hour of attack onset, significantly reduced attack duration and time to attack resolution.