(HealthDay News) – Patients with unpredictable and recurring attacks of acute hereditary angioedema (HAE) may be effectively treated with ecallantide, with relapse occurring in a small proportion of patients and little evidence of rebound.

Jonathan A. Bernstein, MD, of the University of Cincinnati, and associates integrated the results from two double-blind, placebo-controlled studies of patients treated with ecallantide for acute HAE attacks to assess potential attack rebound and relapse rates.

The researchers found that, after four hours, 42 of 70 ecallantide-treated patients showed improvement in three outcome measures, compared to 26 of 71 placebo-treated patients, and were eligible for further rebound/relapse therapy (P=0.006). Of nine ecallantide-treated patients with signs of worsening at 24 hours, one was assessed as likely relapse, two as possible relapse, and one as possible rebound; none were classified as likely rebound. Of the patients with potential rebound/relapse, none experienced new symptoms after dosing. One ecallantide-treated patient required medical intervention.

“These data contribute to the body of evidence demonstrating a durable response to ecallantide treatment of acute HAE attacks,” the authors write. “Attack details and individual patient data reinforce the clinical importance of monitoring patient responses and individualizing therapeutic intervention.”

Several authors disclosed financial ties to pharmaceutical companies, including Dyax, which funded the study and manufactures ecallantide.

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