July 8, 2025 – The FDA has approved the first-ever pill to stop attacks of a rare genetic swelling disorder while they're happening.
The drug, known as sebetralstat but sold as Ekterly, is for adults and children age 12 years or older with hereditary angioedema (HAE), which affects about 1 in 50,000 people and causes sudden and painful swelling that can sometimes be life-threatening. These easy-to-take pills help stop an attack whenever it happens, offering an advantage over other treatments that need to be injected either into the veins or under the skin.
HAE happens when a person has a faulty gene that causes their body to make too little of a protein called C1 inhibitor, or the protein doesn't work well. This protein usually helps control swelling and inflammation in the body. This genetic defect can cause swelling in the face, throat, abdomen, or limbs, which can sometimes be serious.
Those with the condition who have swelling in the abdomen can have stomach pain, vomiting, or diarrhea. Swelling in the throat or face can make it hard to breathe. Even with regular treatment, many people with HAE still have sudden attacks and always need fast-acting medicine available to them.
"As the first orally administered on-demand therapy for HAE attacks, Ekterly provides patients and physicians with an important and welcome advance in HAE treatment options," Anthony J. Castaldo, chief executive officer of the US Hereditary Angioedema Association, said in a statement.
Ekterly was approved after a study involving 136 people with HAE across 20 countries showed that it could quickly relieve symptoms and help end attacks sooner, compared to a placebo, regardless of how severe the attack was. In a follow-up study, many people were able to take the pill within 10 minutes of an attack, and symptoms began to improve in about 1.3 hours, according to a news release from KalVista Pharmaceuticals, the drug's maker.
Ekterly works by blocking an enzyme called plasma kallikrein, which causes swelling. In people with HAE, this enzyme is too active because the C1 inhibitor protein does not work properly. By blocking this enzyme, Ekterly helps stop sudden swelling and pain from happening. The pill lets people treat attacks early, giving them more control and helping doctors lower the impact of the disease. According to KalVista, the medicine will be available right away.
Headaches are the only reported side effect of the new treatment. It's not known if the medicine is safe during pregnancy or breastfeeding, so patients should tell their doctor if they are pregnant, planning to become pregnant, or breastfeeding. Patients should also tell their doctor if they have liver problems or are taking other medicines, especially for fungal or viral infections, or epilepsy.