Interim analysis suggested a trend favoring ecallantide; observed response rate to placebo was substantially higher than described in medical literature.

A double-blind, randomized, controlled trial comparing the safety and effectiveness of conventional therapy with ecallantide to conventional therapy with placebo.

Inclusion Criteria:

• Males and females 18 years of age or older
• Must currently be on ACE inhibitor therapy and have received a dose within 36 hours
• Presenting with ACEIA of the head/neck region within 12 hours after onset
• All females must have a negative urine pregnancy test prior to administration of the study drug. Those who have had a total hysterectomy, bilateral oophorectomy or are two years post-menopausal do not require a pregnancy test.

Exclusion Criteria:

• Hypersensitivity to ecallantide
• Pregnancy or breast feeding
• Patients who have had angioedema and were not concurrently on an ACE inhibitor
• Patients exhibiting urticaria
• Patients who are intubated or who have a tracheostomy related to the current episode of angioedema
• Opinion of the investigator that the patient would not be a good candidate
• Participation in another investigational study within 30 days prior to enrollment

Dyax agreements vary, but Dyax will not prohibit any investigator from publishing. Dyax reviews publications prior to public release and can request deferral by up to 60 days beyond the proposed publication date if necessary to preserve its intellectual property. Dyax can request changes to publications to remove non-study-related confidential information. Dyax can also request deferral of single-center publications until after disclosure of the clinical trial's primary publication.