Ekterly (sebetralstat) for hereditary angioedema

Last updated July 8, 2025, by Margarida Maia, PhD
Fact-checked by Inês Martins, PhD

What is Ekterly for hereditary angioedema?

Ekterly (sebetralstat) is an oral medication approved in the U.S. for the on-demand treatment of acute swelling attacks in children and adults with hereditary angioedema (HAE), ages 12 and older.

Taken as tablets, Ekterly is the first oral on-demand treatment for HAE, offering a more convenient alternative to existing treatments that must be injected under the skin or into the bloodstream. It is meant to be given as soon as symptoms of an attack become evident to help reduce its severity and shorten its duration.

HAE is caused by genetic mutations that generally lead to the excessive production of bradykinin, a molecule that causes blood vessels to widen. This causes fluid to leak into the deeper layers of skin or mucus membranes, triggering the characteristic swelling episodes of HAE.

Developed and marketed by Kalvista Pharmaceuticals, Ekterly works by blocking kallikrein, an enzyme involved in bradykinin production. By reducing bradykinin levels, the medication helps to bring swelling under control and eases symptoms during an attack.

Therapy snapshot

Who can take Ekterly?

Ekterly is approved in the U.S. to treat acute HAE attacks in adults and children, ages 12 and older.

While its prescribing information lists no contraindications, Ekterly should be avoided in people with severe liver impairment. It also should not be taken alongside medications that interfere with CYP3A4, the enzyme that processes Ekterly in the body.

How is Ekterly administered?

Ekterly is available as 300 mg film-coated tablets. The recommended starting dose is two tablets, taken as soon as signs of an HAE attack appear. A second dose may be taken later if symptoms persist, worsen, or return after the first dose.

Dose adjustments may be needed for people with moderate liver impairment or those taking moderate CYP3A4 inhibitors.

Ekterly in clinical trials

Ekterly’s approval in the U.S. was mainly based on data from a Phase 3 clinical trial called KONFIDENT (NCT05259917), which involved 136 adults and children with HAE type 1 or 2.

• In KONFIDENT, all patients had at least three attacks treated — one with 300 mg Ekterly, one with 600 mg Ekterly, and a third with a placebo — in random order. Results showed that the now-approved dose led to the start of symptom relief after a median of two hours, while less than 50% of placebo-treated attacks reached the beginning of symptom relief within 12 hours. The time to a reduction in attack severity and time to having a full attack resolution were also significantly faster with Ekterly. A single dose was sufficient to ease or fully resolve most acute attacks.
• Participants who took part in KONFIDENT or who experienced recurrent swelling attacks could then enter a two-year open-label extension study called KONFIDENT-S (NCT05505916). Interim data showed that patients took Ekterly a median of nine minutes after an attack began — much sooner than the median 41 minutes in KONFIDENT. On-demand treatment with Ekterly was effective for controlling swelling in patients who were already on long-term prophylaxis (preventive treatment) and in those whose swelling affected the larynx (voice box).

Kalvista is now running a Phase 3 clinical trial called KONFIDENT-KID (NCT06467084) to test a different formulation of sebetralstat that dissolves on the tongue in children, ages 2 to 11, with HAE.

Ekterly side effects

The most common side effect reported with Ekterly was headache.

This is the only side effect that occurred in more than 2% of patients given the medication, and was more frequently seen with Ekterly than with a placebo. The medication’s prescribing information contains no other warnings or precautions related to the use of Ekterly.

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