OBJECTIVE: To provide an overview on the current status of emerging therapies 
for hereditary angioedema (HAE) in the United States.
DATA SOURCES: Summary statements were obtained from each pharmaceutical company 
regarding their agent.
STUDY SELECTION: Each agent is undergoing or has completed phase 3, 
double-blind, placebo-controlled trials.
RESULTS: Berinert P, a purified, virus-inactivated, human plasma-derived C1 
inhibitor (C1-INH) concentrate, is being investigated in 2 international, 
multicenter, prospective trials. Experience with this agent in Europe and Canada 
indicates it is effective and safe. Cinryze is a nanofiltered C1-INH replacement 
therapy demonstrated to be effective and safe in acute and prophylactic arms of 
a phase 3, double-blind, placebo-controlled study. Rhucin, a recombinant human 
C1-INH replacement therapy from transgenic rabbits, has been shown to be 
effective and safe in phase 2 and phase 2/3 studies, with an additional phase 3 
study ongoing. DX-88 or ecallantide, a potent and specific inhibitor of plasma 
kallikrein, achieved all primary and secondary efficacy end points in a 
placebo-controlled, double-blind, phase 3 study, with a second phase 3 study 
ongoing. Icatibant, a potent and specific peptidomimetic bradykinin 2 receptor 
antagonist, was studied in 2 phase 3 trials: FAST 1 (For Angioedema Subcutaneous 
Treatment) did not achieve statistical significance for the primary end point 
but did so for secondary end points, whereas FAST 2 achieved statistical 
significance for primary and secondary end points.
CONCLUSIONS: The future treatment of HAE in the United States appears promising 
based on progress being made in drug development for this orphan disease.