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What is Haegarda used for and how does it work?

Medically reviewed by Carmen Pope, BPharm. Last updated on Sep 20, 2023.

Official answer

  • Haegarda is injected subcutaneously (under the skin) to prevent angioedema attacks in adults, adolescents, and children over the age of 6 with hereditary angioedema (HAE).
  • Haegarda is a man-made form of a protein called C1 esterase inhibitor (C1-INH), that naturally occurs in our blood.
  • People with HAE have reduced levels of C1-INH in their blood, which leads to increased blood vessel permeability and attacks of severe swelling in the limbs, face, intestinal tract, and airway.
  • Haegarda replaces missing C1-INH, preventing the generation of bradykinin and other substances that increase the permeability of blood vessels.

Haegarda is a brand of complement C1 esterase inhibitor (C1-INH). C1-INH is a man-made form of a protein in blood that helps control swelling in the body and is used to treat people with a condition called hereditary angioedema who lack C1-INH.

Hereditary angioedema is a genetic disorder that causes attacks of severe swelling in the limbs, face, intestinal tract, and airway.

What is Haegarda?

Haegarda is a man-made form of the C1-INH.

The main purpose of C1-INH is to regulate the coagulation pathway (the process that causes our blood to clot), the fibrinolytic system (the process that removes and degrades clots after blood vessels are repaired), and to control the production of bradykinin, which is a protein fragment that increases the movement of fluid through blood vessel walls, resulting in swelling and inflammation.

How does Haegarda work?

People with hereditary angioedema (HAE) have low levels of naturally occurring C1-INH in their blood. Haegarda adds working C1-INH, which brings levels of C1 back up and closer to normal, reducing bradykinin production, decreasing the permeability of blood vessels and reducing swelling.

Haegarda is used to reduce the risk of attacks of angioedema in people and children over the age of 6 with HAE.

How is Haegarda given?

Haegarda is given by slow subcutaneous (just under the skin) injection, usually twice a week (every three to four days). It can either be given by a trained nurse or people can be taught how to self-administer it themselves.

The dosage of Haegarda is based on body weight, so it is individualized for each person.

Are there any other types of C1 inhibitors?

Yes, there are three other types of C1 inhibitors:

  • Berinert, which is used to treat attacks of angioedema
  • Ruconest, which is used to treat attacks of angioedema
  • Cinryze, which is given every three to four days by intravenous injection to prevent attacks of angioedema.

What is hereditary angioedema?

Hereditary angioedema is a genetic disorder characterized by severe swelling in the limbs, face, intestinal tract, and airway. There are three known types:

Type I and II caused by mutations in the Serping I gene and Type III which is caused by mutations in the F12 gene.

The Serping I gene provides instructions for making the C1 inhibitor protein, which helps control inflammation. Mutations in this gene can lead to either reduced levels of C1 protein in the blood or the production of a C1 inhibitor that functions abnormally. When levels of this C1 protein are decreased, excessive amounts of another protein fragment, called bradykinin are generated. Bradykinin increases the leakage of fluid through the walls of blood vessels into body tissues, promoting inflammation. This causes fluid to accumulate which causes the swelling characteristic of hereditary angioedema type I and type II.

Some cases of hereditary angioedema type III are associated with mutations in the F12 gene. This gene codes for an important protein that helps our blood to clot, known as coagulation factor XII. Factor XII is also an important stimulator of inflammation and is involved in bradykinin production. Certain F12 mutations produce Factor XII with an increased activity, which generates more bradykinin, leading to blood vessel wall leakage and angioedema. The gene mutations responsible for other types of hereditary angioedema III have not yet been discovered.

How effective is Haegarda?

Research has shown that Haegarda can reduce the risk of HAE attacks by about 95%, and eliminates the need for rescue medication in 99% of people (although rescue medication still needs to be kept on hand just in case).


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