Ecallantide for the treatment of acute attacks in hereditary angioedema

Marco Cicardi, Robyn J. Levy, Donald L. McNeil, H. Henry Li, Albert L. Sheffer, Marilyn Campion, Patrick T. Horn, William E. Pullman

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247 Scopus citations


Background: Hereditary angioedema is a rare genetic disorder characterized by acute, intermittent, and potentially life-threatening attacks of edema of the skin and mucosa. We evaluated ecallantide, a newly developed recombinant plasma kallikrein inhibitor, for the treatment of acute attacks of angioedema. Methods: In this double-blind, placebo-controlled trial, patients with hereditary angioedema presenting with an acute attack were randomly assigned, in a 1:1 ratio, to receive subcutaneous ecallantide, at a dose of 30 mg, or placebo. Two measures of patient-reported outcomes were used to assess the response: treatment outcome scores, which range from +100 (designated in the protocol as significant improvement in symptoms) to -100 (significant worsening of symptoms), and the change from baseline in the mean symptom complex severity score, which range from +2 (representing a change from mild symptoms at baseline to severe symptoms after) to -3 (representing a change from severe symptoms at baseline to no symptoms after). The primary end point was the treatment outcome score 4 hours after study-drug administration. Secondary end points included the change from baseline in the mean symptom complex severity score at 4 hours and the time to significant improvement. Results: A total of 71 of the 72 patients completed the trial. The median treatment outcome score at 4 hours was 50.0 in the ecallantide group and 0.0 in the placebo group (interquartile range [IQR], 0.0 to 100.0 in both groups; P = 0.004). The median change in the mean symptom complex severity score at 4 hours was -1.00 (IQR, -1.50 to 0.00) with ecallantide, versus -0.50 (IQR, -1.00 to 0.00) with placebo (P = 0.01). The estimated time to significant improvement was 165 minutes with ecallantide versus more than 240 minutes with placebo (P = 0.14). There were no deaths, treatment-related serious adverse events, or withdrawals owing to adverse events. Conclusions: Four hours after administration of ecallantide or placebo for acute attacks of angioedema in patients with hereditary angioedema, patient-reported treatment outcome scores and mean symptom complex severity scores were significantly better with ecallantide than with placebo. (Funded by Dyax; number, NCT00262080.)

Original languageEnglish (US)
Pages (from-to)523-531
Number of pages9
JournalNew England Journal of Medicine
Issue number6
StatePublished - Aug 5 2010
Externally publishedYes

ASJC Scopus subject areas

  • General Medicine


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