The use of plasma-derived C1 inhibitor in the treatment of hereditary angioedema.

C1-inhibitor (C1-INH) deficiency is the genetic defect underlying hereditary angioedema (HAE). Subjects with HAE suffer from recurrent angioedema that may result in death when it affects the larynx, severe abdominal pain when it affects the gastrointestinal mucosa and disfiguration when it affects the skin. The use of plasma-derived C1-INH concentrates to revert angioedema in HAE patients started in the 1970s. Since that time, three different preparations arrived onto the market, two of them are still present. Controlled studies and a large clinical experience indicate that C1-INH concentrate should be considered the treatment of choice for disabling angioedema attacks at any site. Efficacy has also been shown in preventing angioedema induced by invasive medical manoeuvres. Limited experience with repeated weekly infusions indicates that C1-INH can be used for long-term prophylaxis in selected patients. The safety profile is excellent and there are no reports of transmission of viral infections with the preparations available at present. C1-INH is licensed only in a limited number of countries. Clinical trials are ongoing at present to expand registration.