Hereditary angioedema: a current state-of-the-art review, VIII: current status of emerging therapies.

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.