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Does heparin prophylaxis prevent exacerbations of hereditary angioedema?
Journal article   Open access   Peer reviewed

Does heparin prophylaxis prevent exacerbations of hereditary angioedema?

John M Weiler, Susan A Quinn, George G Woodworth, Donald D Brown, Teresa A Layton and Karen K Maves
Journal of allergy and clinical immunology, Vol.109(6), pp.995-1000
2002
DOI: 10.1067/mai.2002.124892
PMID: 12063530
url
https://doi.org/10.1067/mai.2002.124892View
Published (Version of record) Open Access

Abstract

Background: Hereditary angioedema (HAE) is a rare disorder characterized by episodes of angioedema of the skin, mucous membranes, and gastrointestinal tract resulting from a defect in the gene that produces C1 esterase inhibitor. Although in vitro laboratory data and past reports suggested that heparin might be efficacious in preventing HAE attacks, no controlled study has been reported to examine heparin's efficacy in this regard. Objectives: We sought to determine the safety and efficacy of inhaled and subcutaneous heparin versus that of placebo in the prevention of HAE attacks. Methods: We performed a double-blind, double-dummy, saline placebo-controlled, randomized, 3-way crossover study with 11 visits. Results: The study was designed to enroll 24 patients. Twenty-two patients were randomized and received the study drug. Patients did not have a significant decrease in average flare intensity after they received injected or inhaled heparin compared with that seen after placebo, the primary endpoint. However, when patients received injected heparin, they had a statistically significant decrease in average flare intensity compared with that seen with inhaled heparin after a normalizing transformation was applied. When the means are back transformed, this translates into median flare intensities of 9.2, 8.0, and 5.1 in the patients treated with inhaled heparin, placebo, and injected heparin, respectively. There were no significant differences when individual symptoms were examined, when total numbers of flares over a 6-week observation period were examined, or when global evaluations by the patients and investigators were evaluated. Adverse event severity was fairly uniform across treatments, with the majority of events classified as moderate and the remainder split between mild and severe. Injected heparin treatment was associated with higher rates of relatedness than other treatments, which was partially explained by 17 adverse events specifically related to the injection process itself (tenderness, bruising, redness, pain, and itching at the injection site). The injection treatment was also associated with a larger overall number of reported adverse events (70 vs 48 in the placebo treatment). Tenderness and bruising at the injection site were entirely confined to the injected heparin treatment. Conclusions: Injected and inhaled heparin failed to attenuate average flare intensity, the primary endpoint, compared with placebo. Interestingly, after patients injected heparin, they had a significant decrease in average flare intensity compared with that seen after inhalation of heparin. There were no differences among groups in other efficacy parameters. Taken together, these data indicate that commercial heparin was ineffective in preventing exacerbations of HAE.
Immunopathology Allergic diseases Biological and medical sciences Blood. Blood coagulation. Reticuloendothelial system Medical sciences Pharmacology. Drug treatments Skin allergic diseases. Stinging insect allergies

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