Haegarda received U.S. Food and Drug Administration (FDA) approval in June 2017. The treatment also became available in Quebec, Canada, in February 2020.
How does Haegarda work?
Hereditary angioedema is characterized by a 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.
After it’s been dissolved in water, the white freeze-dried powder is meant to be self-administered by injection under the skin.
Haegarda in clinical trials
A Phase 1/2 (NCT01576523) clinical trial investigated the pharmacokinetics (movement in the body), pharmacodynamics (effect on the body), and safety of Haegarda. Three different doses given as twice-weekly injections under the skin for a month were found to be safe and well-tolerated in patients with type 1 or 2 hereditary angioedema. The largest dose was four times the smallest, and the middle dose twice the amount of the smallest.
The two highest doses were able to keep levels of C1 esterase inhibitor 40% above normal or the amount required to keep a person safe from angioedema attacks. The study also found that injecting Haegarda under the skin led to a more consistent delivery of the medication than delivering it directly into the bloodstream. The most common side effects of the treatment were pain and swelling at the injection site.
A Phase 3 clinical trial (NCT01912456) showed that injections of 40IU per kg dose of Haegarda reduced angioedema attacks by 89%, while a dose of 60IU per kg reduced the attacks by 95%. The results applied to patients with type 1 or 2 hereditary angioedema. Forty percent of patients who received the higher dose of Haegarda experienced no angioedema attacks. When attacks did occur, they were generally milder and less frequent. The trial ended in 2015, with the results published in the New England Journal of Medicine.
CSL Behring conducted an extension study (NCT02316353) of the Phase 3 trial to determine Haegarda’s long-term safety and efficacy. Patients who completed the initial trial were eligible to enroll and continue to receive the same dose of treatment for up to three years.
The trial ended in September 2017 and the results were published in the Journal of Allergy and Clinical Immunology. A total of 126 patients were involved in the study and had on average 4.3 angioedema attacks per month before joining the study. Patients treated with the 40IU-per-kg dose decreased their attacks to an average 1.3 attacks per year, and those on the 60IU-per-kg experienced an average of one attack per year.
Haegarda is the first preventive medication that can be injected under the skin to treat hereditary angioedema.
The most common side effects of Haegarda 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.
Last updated: Feb. 7, 2020
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