Ecallantide: its pharmacology, pharmacokinetics, clinical efficacy and tolerability

Ecallantide (Kalbitor (R), Dyax Corporation) is a highly specific recombinant plasma kallikrein inhibitor developed for treatment of hereditary angioedema (HAE). Advantages of this agent over plasma-derived treatments are that it poses no risk of viral contamination, is highly selective, has a quick onset of action and can be administered subcutaneously. In clinical trials, ecallantide appears to be a safe and effective drug useful for the treatment of HAE patients suffering from an acute attack. Ecallantide was found to be superior compared with placebo in relieving symptoms, decreasing the severity of attacks and shortening the duration of attacks. The primary safety concern appears to be related to hypersensitivity reactions. Phase IV postmarketing surveillance studies to monitor the incidence of these reactions will be implemented by the company now that the drug has been US FDA approved.