Reducing the burden of hereditary angioedema (HAE) could be possible with adequate dosing and frequency of administration of C1 inhibitor (C1-INH), even for patients with highly symptomatic HAE activity, according to data from randomized controlled trials evaluating the administration of C1-INH replacement therapy as long-term prophylaxis in patients with HAE.
Up to 83% of patients receiving plasma-derived C1-INH (60 IU/kg) experienced an HAE attack reduction threshold of 70% or greater, and up to 58% achieved an HAE attack reduction threshold of 90% or greater.
“The increasing patient percentages treated with C1-INH replacement therapy as long-term prophylaxis meeting these high thresholds reinforces hopes and expectations that “attack freedom” is achievable, including for those with moderate or severe disease,” Longhurst and Valerieva wrote in a review article published in the Journal of Asthma and Allergy.
The results of the trials also suggest a clear dose-response for subcutaneous administration of C1-INH and a dose-dependent benefit for intravenous prophylaxis.
Forty-five percent of patients receiving plasma-derived C1-INH, 1000 U, twice weekly, experienced an HAE attack reduction threshold of 70% or greater, and 23% achieved an HAE attack reduction threshold of 90% or greater.
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Prophylaxis with recombinant human C1-INH, 50 U/kg, twice weekly, seems to be of intermediate benefit for HAE attack rate reduction, with 52% of patients experiencing an HAE attack reduction threshold of 75% or greater, and 26% experiencing a reduction threshold of 90% or greater.
Moreover, 26% and 9% of patients receiving recombinant human C1-INH, 50 U/kg, weekly, achieved an HAE attack reduction threshold of 75% and 90%, respectively.
“Further exploration of the potential impact of patient-related and disease-related variables (eg, baseline disease frequency) would be valuable to optimize long-term management of HAE and minimize risk of breakthrough HAE attacks,” Longhurst and Valerieva wrote.
Longhurst HJ, Valerieva A. A review of randomized controlled trials of hereditary angioedema long-term prophylaxis with C1 inhibitor replacement therapy: alleviation of disease symptoms is achievable. J Asthma Allergy. Published online March 9, 2023. doi:10.2147/JAA.S396338