Acute Treatment for Hereditary Angioedema (HAE)

Hereditary angioedema is a rare genetic condition. It causes sudden and severe swelling in the body. This swelling can happen in the stomach, face, and throat. An attack on the throat can be very dangerous.¹

What is hereditary angioedema?

HAE is a genetic disorder that affects the blood vessels. People with HAE lack a specific blood protein, or the protein does not work as it should. This protein is called C1 esterase inhibitor. Without it, a chemical called bradykinin cannot break down. This leads to fluid build-up and causes severe swelling.¹

Swelling attacks can last for 2 to 5 days if untreated. And for many people with HAE, swelling attacks occur 3 or more times per month. Triggers can include emotional stress, physical injuries, or dental work. Swelling can cause intense pain and disrupt daily life. Caregivers can help watch for early signs of an attack.¹

Abdominal attacks cause severe pain, nausea, and vomiting. These symptoms can mimic a surgical emergency. Proper diagnosis is necessary to avoid unnecessary surgeries. Knowing the signs helps caregivers react quickly.¹

Goals of acute treatment

The main goal of acute treatment is to stop the swelling fast. Quick treatment reduces swelling and pain. It helps people with HAE return to normal activities sooner.²

Doctors want people to treat attacks at the very first sign. Early treatment keeps the swelling from getting worse. It also lowers the risk of severe complications.²

Another goal is to reduce the total time of the attack. Without treatment, attacks can last for several days. Quick use of drugs can shorten this time significantly. This allows people to return to school or work.²

How acute treatments work

Acute drugs work by stopping the signals that cause swelling. During an attack, the body makes too much of a peptide. This peptide is called bradykinin. Bradykinin makes blood vessels leak fluid into nearby tissues.^1,2

The contact activation system controls the production of bradykinin. C1 esterase inhibitor acts as a brake on this system and keeps bradykinin levels in check. When the brake is missing, the system runs unchecked. This causes the uncontrolled release of bradykinin.^1,2

Some acute drugs replace the missing C1 inhibitor protein. Other drugs block the proteins that create bradykinin. A third type blocks bradykinin from binding to cells. All these methods help stop fluid leakage quickly.²

Plasma-derived drugs come from human blood donations. These donations undergo strict screening for safety. Recombinant drugs are made in a laboratory setting. Both types effectively replace the missing protein brake.

Examples of acute drugs for HAE attacks

The US Food and Drug Administration (FDA) has approved several acute drugs. Some acute drugs require an intravenous injection into a vein. Other drugs use a subcutaneous injection under the skin. The newest option is a simple oral capsule taken by mouth. Your choice depends on age and comfort level.^3,4

Examples of acute medicines for HAE are:^3,4

• Berinert® (plasma-derived C1 esterase inhibitor) – an intravenous injection. It is approved across all age groups. It replaces the missing protein C1-INH in the bloodstream.
• Ekterly® (sebetralstat) – an oral tablet. It is approved for adults and children ages 12 and older. It is the first oral on-demand treatment for attacks. It blocks plasma kallikrein to reduce the production of bradykinin.
• Firazyr® (icatibant) – a subcutaneous injection. It is approved for adults 18 years and older. Adults can self-administer this drug. It blocks bradykinin from binding to its receptors.
• Kalbitor® (ecallantide) – a subcutaneous injection. It is approved for adults and children ages 12 and older. A healthcare professional must give this drug. This is due to a risk of severe allergic reactions. It works by blocking plasma kallikrein, a protein that produces bradykinin.
• Ruconest® (recombinant human C1 inhibitor) – an intravenous injection. It is approved for adults and adolescents. This drug is not made from human plasma. It replaces the missing protein C1-INH in the bloodstream.

What are the possible side effects?

Side effects can vary depending on the specific treatment/drug you are taking. Some people experience pain or redness at the injection site. Others may experience headaches, nausea, or diarrhea.^3,4

These are not all the possible side effects of acute HAE treatments. Talk to your doctor about what to expect when taking acute HAE treatments. You should also call your doctor if you have any changes that concern you when taking acute HAE treatments.

Other things to know

Before beginning treatment for hereditary angioedema, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.

Acute treatments are vital for managing sudden swelling attacks. They help stop symptoms fast and improve safety. Talk to your doctor to choose the best option for your needs. Caregivers and loved ones can support you during this process.