Hereditary angioedema (HAE) is a rare genetic condition that can cause severe swelling that is painful and can be life-threatening. These attacks can occur suddenly. In 2025, Ekterly (sebetralstat) became the first medicine taken by mouth to treat sudden attacks of HAE. Other medicines used to treat sudden HAE attacks are given as injections.
What Is Hereditary Angioedema?
HAE is a condition that causes certain parts of the body to swell, such as your face, hands, feet, gut, throat, or other areas. If it affects the gut, it can cause severe stomach pain. If it affects the airways, it can be life-threatening. HAE is a genetic condition, meaning that it is passed down in families.
How Does Ekterly Work for Hereditary Angioedema?
The swelling caused in HAE happens because there is not enough of a certain protein called complement component C1 esterase inhibitor (C1 inhibitor). People with HAE either do not make enough of the protein (type I HAE) or the protein that they do make does not work properly (type II HAE).
One of the jobs of the C1 inhibitor protein is to keep the amount of bradykinin that is made in the body in check. This is done by a chain of events that involves substances called C1 inhibitor, kallikrein, and bradykinin. The role of each of these substances is described in the table below.
Substance | Normal Role | Problem in Someone With HAE |
C1 inhibitor |
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Kallikrein |
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Bradykinin |
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Bradykinin is a substance that your body naturally makes when there is stress, injury, or infection in the body. Too much bradykinin can push fluid into nearby areas of your body, which leads to sudden swelling.
Ekterly works by preventing kallikrein from making too much bradykinin. This helps reduce swelling.
How Do I Take Ekterly?
As soon as you start to have symptoms that you think are related to HAE, you should take your dose of Ekterly. You should take two tablets right away. You may take a second dose if needed if you are still having symptoms after three hours or if the symptoms come back. Talk to your health care provider about the dose of Ekterly that is right for you. The dose may need to be changed if you are taking other medicines that interact with Ekterly or if you have liver problems.
How Was Ekterly Studied?
Ekterly was studied in 110 people ages 12 or older. People in this study took Ekterly at a dose of either 300 milligrams or 600 milligrams, or they took a placebo pill. Placebo pills do not contain an active medicine.
To determine if Ekterly worked, the researchers looked at how fast the symptoms of HAE got better. They also looked at how fast the severity of symptoms got better and how many people recovered completely 24 hours after treatment.
To determine if Ekterly was safe, the researchers collected information on what types of side effects people experienced during the study.
Who Was Included in the Study?
To be in this study, people had to be 12 or older and have a diagnosis of type I or type II hereditary angioedema. They also had to have had two recent HAE attacks.
Most people in this study were between 25 and 49 years old, and about 12% were between 12 and 18 years old. About 40% of people in this study were male. People in this study were mostly White (about 84%), about 1% were Black, and about 9% were Asian. About 6% were Hispanic or Latino.
About 92% had type I HAE and about 8% had type II HAE. About 22% were taking medicine to prevent HAE.
For those who had attacks during the study period, about 43% rated them as mild, about 39% rated them as moderate, about 14% rated them as severe, and about 3% rated them as very severe.
The location of the attacks varied in this study.
Location | % of attacks in this location |
Stomach | 43% |
Arms, hands | 29% |
Legs, feet | 24% |
Head, face, neck | 11% |
Trunk or midsection | 6% |
Genital area | 3% |
Throat | 3% |
About 44% of people in this study took their dose (or placebo) within 30 minutes of noticing symptoms. About 11% took it within 30 to 60 minutes, and about 44% took it after an hour of first noticing symptoms.
What Are the Main Benefits of Ekterly Based on the Study?
People who took Ekterly started to feel better faster than those who took the placebo pill. People who took Ekterly also saw their symptoms become less severe or go away faster than those who took the placebo pill. The table below shows the middle value out of everyone’s result.
Ekterly 300 mg | Ekterly 600 mg | Placebo pill | |
Time to beginning of symptom improvement | 1.61 hours | 1.79 hours | 6.72 hours |
Time to symptoms becoming less severe | 9.27 hours | 7.75 hours | More than 12 hours |
Within 24 hours of taking a first dose, more people who took Ekterly 300 milligrams (42.5%) or Ekterly 600 milligrams (49.5%) were free of symptoms (complete resolution of attack) compared to those who took the placebo pill (27.4%).
Your results may differ from what was seen in clinical studies.
What Side Effects of Ekterly Were Seen in the Study?
Side effects were similar between those who took Ekterly and those who took the placebo pill. Headache was a little more common in people treated with Ekterly. About 3.2% of people who took Ekterly in the study had a headache compared to 1.2% of those who took placebo.
Your results may differ from what was seen in clinical studies.
Are There Any Interactions With Other Medicines?
Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, or other supplements that you are using or have used recently. This can help them determine the best treatment plan for you.
Certain medicines can affect the blood levels of Ekterly, and Ekterly can affect the blood levels of other medicines. You cannot take Ekterly if you are taking certain medicines. In some cases, your health care provider may have to change the dose of Ekterly or of your other medicines.
Are There Any Special Steps Required to Get Ekterly?
You must get Ekterly from a specialty pharmacy. Ekterly is available through a program called Kalvista Cares. This is a patient support program that can help you with getting started, including:
- Understanding your insurance coverage
- Finding information on HAE
- Helping you find ways to afford Ekterly
- Helping to prevent delays in starting Ekterly
- Working with your specialty pharmacy to make sure you receive Ekterly
- Helping to prevent any problems with continuing Ekterly
There may be cost assistance to help you afford Ekterly. You may have options even if you do not have health insurance. Your health care provider can help you get started, or you can call 844-432-3322 or visit www.ekterly.com/patient-support-program.
