Haegarda: 7 things you should know

Medically reviewed by Carmen Pope, BPharm. Last updated on May 29, 2024.

1. How it works

• Haegarda is a brand (trade) name for a man-made form of a protein called C1 esterase inhibitor, which naturally occurs in blood. Haegarda may be used to prevent attacks of hereditary angioedema (HAE) in adults and children aged 6 years and older. HAE is a rare genetic condition that occurs in people with low levels of certain proteins (C1-INH and C4) in their bodies.
• The main purpose of the C1 inhibitor protein 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.
• Haegarda replaces missing C1-INH, which reduces bradykinin production, decreasing the permeability of blood vessels and reducing swelling.
• Haegarda belongs to the class of medicines known as C1 esterase inhibitors. It may also be called a hereditary angioedema agent.

2. Upsides

• May be used to prevent angioedema attacks in adults, adolescents, and children aged 6 years and older with hereditary angioedema (HAE).
• Reduces swelling in the limbs, face, intestinal tract, and airway.
• The usual dosage is 60 units per kg body weight subcutaneously (SC) twice weekly (every 3 or 4 days).
• Administered just under the skin (subcutaneously).
• Intended for self-administration twice weekly (every 3 or 4 days) after appropriate training from a healthcare professional. Most people find it easy to learn how to self-administer Haegarda.
• Available as a 2000 IU vial and a 3000 IU vial.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Injection site reactions, nasopharyngitis, dizziness, headache, rash, and itch are the most common side effects reported.
• Severe hypersensitivity reactions (severe allergies) have been reported. Advise people to report any signs of an allergic reaction such as hives, rash, fast heartbeat, difficulty breathing (wheezing), chest tightness, feeling light-headed or faint, swelling of your face, lips, tongue, or throat during or after the administration of Haegarda and to seek immediate help. Note that hypersensitivity reactions may have similar symptoms to HAE attacks. If a hypersensitivity reaction occurs, discontinue Haegardaand administer appropriate treatment, including epinephrine if necessary.
• Serious thromboembolic events (blood clots) have been reported with C1 esterase inhibitor products, such as Haegarda, The risk is greater in those with an indwelling catheter, prior history of thrombosis, underlying atherosclerosis, use of oral contraceptives, certain androgens, morbid obesity, or immobility. Weigh up the benefits of Haegarda in these people versus the risk of an event.
• Because Haegarda is made from human blood there is a risk of transmitting infectious agents, such as viruses, and theoretically, the Creutzfeldt-Jakob disease vector.
• Needs to be given by subcutaneous injection every three or four days to prevent angioedema attacks in people with HAE.
• Requires reconstitution before self-administration. The dosage of Haegarda is based on body weight, so it is individualized for each person.
• Not suitable for people who have developed life-threatening, immediate hypersensitivity reactions, including anaphylaxis, to Haegarda or any similar products.
• There is also the potential for immunogenicity and antibody formation.
• People can be taught how to self-administer Haegarda.
• Does not treat attacks of HAE. Other medications, such as Berinert or Ruconest do this.
• The safety of Haegarda in children under the age of 6 has not been established.
• There is no data regarding the use of Haegarda in pregnant women, and animal studies have not been conducted. It is unknown if Haegarda can cause fetal harm or affect reproduction capacity. Only give to pregnant women if needed. There is no data regarding the presence of Haegarda in human milk or its effects on milk production.
• No generic is available.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

• Haegarda works by replacing missing C1 protein in the blood of adults and children over the age of 6 with hereditary angioedema (HAE) preventing the generation of bradykinin and angioedema attacks. Haegarda can be self-administered at home subcutaneously (under the skin) every 3 or 4 days, although some people can be taught how to self-administer. Injection site reactions, hypersensitivity reactions, nasopharyngitis, and dizziness are the most common side effects reported.

5. Tips

• If you have any signs of an allergic reaction while you are administering Haegarda or soon after, immediately tell your healthcare professional. Signs of an allergic reaction may include hives, rash, fast heartbeat, difficulty breathing (wheezing), chest tightness, feeling light-headed or faint, and swelling of your face, lips, tongue, or throat.
• Also report any signs of a blood clot, such as swelling, pain, discoloration, a feeling or warmth, in an arm or leg, shortness of breath, chest pain or discomfort that worsens on deep breathing, numbness or weakness on one side of the body.
• Prepare the Haegarda vial as per the manufacturer's instructions and use the supplied diluent. Do not use if the vial is past its use-by date, contains visible particles, or is discolored. Use the diluted solution within 8 hours of reconstitution. Store at room temperature and do not put it in the refrigerator during these 8 hours.
• Because Haegarda is a blood product, it does carry a risk for transmission of infectious agents such as viruses, but this is unlikely because the risk of transmitting disease has been reduced by carefully selecting blood donors, testing donors for infections, and inactivating viruses during the manufacturing process.
• Haegarda is usually administered every three or four days. Keep to your regular dosing schedule and do not miss any doses. If you do miss a dose, administer it as soon as you remember, but do not double up on doses. If you are traveling, take enough Haegarda with you to continue with your regimen. Do not attempt to self-administer unless you have been taught how to do so by your healthcare provider. Make sure you follow their instructions about administration. Haegarda needs to be injected just under the skin (subcutaneously).
• Haegarda has not been studied in pregnant or breastfeeding women. Talk to your healthcare provider about the risk of taking this drug during pregnancy or breastfeeding especially if you are considering trying to become pregnant. Tell your doctor if you inadvertently become pregnant.

6. Response and effectiveness

• Research has shown that Haegarda can reduce the risk of HAE attacks by about 95%, and eliminate the need for rescue medication in 99% of people (although rescue medication still needs to be kept on hand just in case).
• Trials of 14 weeks duration reported the average number of attacks with Haegarda was 0.52 attacks per month compared with 4.03 attacks per month with placebo (an inactive treatment).

7. Interactions

Medicines that interact with Haegarda may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with Haegarda. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Haegarda include:

• anti-cancer medications such as carfilzomib
• danazol
• epoetins
• hormones, such as estrogen, estradiol, nandrolone, or testosterone
• lenalidomide
• raloxifene
• streptokinase
• thalidomide
• thrombolytics such as alteplase, anistreplase, or urokinase.

Note that this list is not all-inclusive and includes only common medications that may interact with Haegarda. You should refer to the prescribing information for Haegarda for a complete list of interactions.

References

• Haegarda (human c1-esterase inhibitor) Updated 09/2022. CSL Behring GmbH. https://www.drugs.com/pro/haegarda.html

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Haegarda only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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