Haegarda is a an approved therapy by CSL Behring aimed at preventing hereditary angioedema attacks.

It received U.S. Food and Drug Administration (FDA) approval for patients ages 12 and up in June 2017. The FDA extended the approval to include children ages 6 and up in September 2020. The treatment also became available in Quebec, Canada, for patients ages 12 and up in February 2020.

How does Haegarda work?

Hereditary angioedema is characterized by the deficiency of an enzyme called the C1 esterase inhibitor. Without this enzyme, the body produces overwhelming amounts of an inflammatory substance called bradykinin, which leads to tissue swelling. Therefore, people with hereditary angioedema experience recurrent and unpredictable flare-ups. The main manifestations of these flare-ups are swelling in the mucous membranes of the lungs and intestinal tract as well as under the skin.

Haegarda provides the body with the C1 esterase inhibitor it needs, keeping the levels high as the body slowly absorbs and processes it.

Patients can self-administer the white freeze-dried powder by subcutaneous (under-the-skin) injection after dissolving it in water.

Haegarda in clinical trials

A Phase 1/2 trial (NCT01576523) investigated the pharmacokinetics (movement in the body), pharmacodynamics (effect on the body), and safety of Haegarda. Results showed that three different doses given as twice-weekly subcutaneous injections for a month were safe and well tolerated in patients with type 1 or 2 hereditary angioedema.

The two highest doses were able to keep levels of C1 esterase inhibitor 40% above normal. This is the amount necessary to keep a person safe from angioedema attacks. Injecting Haegarda subcutaneously also led to more consistent delivery of the medication than giving it intravenously, or into the vein. The most common side effects of the treatment were pain and swelling at the injection site.

A Phase 3 trial, called COMPACT (NCT01912456), showed that injections of 40 international units (IU) per kilogram of Haegarda reduced angioedema attacks by 89% and a dose of 60 IU/kg reduced the attacks by 95% in patients with type 1 or 2 hereditary angioedema. Of the patients who received the highest dose of Haegarda, 40% experienced no angioedema attacks. When attacks did occur, they were generally milder and less frequent. The trial ended in 2015, with results published in the New England Journal of Medicine.

CSL Behring conducted an open-label extension study (NCT02316353) of the COMPACT trial to determine Haegarda’s long-term safety and efficacy. Patients who completed the initial trial were eligible to continue to receive the same dose of treatment for up to three years.

Results of the trial, which ended in September 2017, appeared in the Journal of Allergy and Clinical Immunology. A total of 126 patients took part in the study. They had an average of 4.3 angioedema attacks per month before joining the study. Patients treated with the 40 IU/kg dose had an average of 1.3 attacks per year. Those on the 60 IU/kg experienced an average of one attack per year.

An additional analysis of the open-label extension study showed that 10 of the 126 patients who received treatment were older than 65 (range of 65–72).  Eight of the 10 patients had additional health problems. Six of them were taking more than five medications for things other than hereditary angioedema such as high blood pressure and diabetes. Results showed that six of the nine patients had a 50% or greater reduction in the number of acute attacks compared with before study enrollment.

The open-label extension also included a subset of patients under age 17 (range of 8–16). Results from this group of patients showed a 97% reduction in the median number of attacks per month. All patients had fewer than one attack per four-week period. Four patients had fewer than one attack per year, and one patient was attack-free during the trial period.

Other information

Haegarda is the first preventive medication that can be injected subcutaneously to treat hereditary angioedema.

The most common side effects are pain and swelling at the injection site, hypersensitivity reactions (such as itchiness, rash, hives, difficulty breathing, and chest tightness), common cold symptoms, and dizziness.

Other C1 esterase inhibitors include Berinert, also by CSL Behring, and Cinryze, by Shire (now part of Takeda Pharmaceutical). Both are injected intravenously.


Last updated: Nov. 24, 2020


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