Ekterly: An Expert’s Perspective

Medically Reviewed by Michelle Vermeulen, PharmD on September 23, 2026

By Marc Riedl, MD, as told to Rachel Reiff Ellis

Marc Riedl, MD, is an allergist-immunologist and clinical director of the U.S. HAEA Angioedema Center at UC San Diego. The information here represents his knowledge and experience as a medical professional.

Sebetralstat (Ekterly) is the first oral medication approved to treat sudden attacks of hereditary angioedema (HAE). It is a rescue medicine that you take as soon as you notice swelling or other symptoms of an attack. The goal is to stop the attack as quickly as possible so you can return to your usual activities. If you have HAE, experts recommend that you always have access to an on-demand treatment and know how to use it.

Ekterly is a type of medication called a kallikrein inhibitor. Kallikrein is a protein that helps your body produce bradykinin, a substance that can cause swelling. HAE is usually caused by not having enough of a protein called C1 inhibitor or having C1 inhibitor that does not work properly. 

Without enough working C1 inhibitor, kallikrein can become overactive and produce too much bradykinin. Ekterly blocks kallikrein, reducing bradykinin production and helping stop the swelling. The FDA approved Ekterly in July 2025.

We spoke with Marc Riedl, MD, an allergist-immunologist and clinical director of the U.S. HAEA Angioedema Center at UC San Diego, to learn more about how Ekterly works and what else you need to know about this treatment. 

Ekterly was the first oral on-demand treatment for HAE attacks in people ages 12 years and older. Its approval was a real step forward because while we've had effective on-demand treatments for HAE for several years, all the available options up until recently were injected medicines. Ultimately — and understandably — people don't love to give themselves shots. This leads to people either avoiding using treatment at all or delaying using it, because they think, "I don't really want to take this medicine. It hurts." And the longer you wait to treat an HAE attack, the worse it is. 

We've always encouraged people: Use rescue medicine as early as you can, within the first hour if possible. The swelling gets increasingly severe up to about 24 hours, and the longer it's there, the longer it will take to go away. But we saw lots of delays and even people not treating their attacks because the treatment itself was so unpleasant with some of the injected medicines. With an oral treatment, we've already started to see this burden or anxiety of treatment recede, because you can take a couple of tablets to get the same effect as the injected medicines. People treat their attacks earlier, they treat more attacks, and they do better overall.

In a rigorous study (KONFIDENT) that looked at how well Ekterly works, people with HAE who took the medicine started to feel better between one and two hours, depending on the dose. Also, more than 90% of attacks were getting better with a single dose before a second dose was needed or taken. That's right in line with what we see with the injected medicines. We don't have head-to-head studies, so we can't yet say one drug is better than the other. 

It takes some time for the fluid that's leaked out — the swelling itself — to go down, so they may not have been completely back to normal in that time frame, but they were clearly getting better, not worse. And when you talk to people with HAE, that's important to them. They know that once they're starting to get better, that they're on the road to getting back to doing what they want to do.

There have been a few reported side effects, but largely, studies have been very reassuring with not many. In the KONFIDENT study, a headache was the most common side effect, but it happened in only about 3% of the people who took the medicine, so very low numbers. Rarely, people reported some fatigue and a little bit of nausea. So far, the safety and the tolerability have really been reassuring, and it's looking like there aren't many side effects to be concerned about.

 

Ekterly is a tablet. It looks like your average pill. The recommended dose for most people is two tablets as a single treatment. You can take a second dose after three hours or more if your swelling is recurring, or you're not seeing sufficient relief. There are no food requirements for taking it, which is important, because, again, people don't plan for these attacks, so you kind of need to take it whether you can eat or not. 

The other cool thing is that there is in development an orally disintegrating tablet (ODT) for kids, which will be easier to take than tablets. Even though this medicine is currently only approved for 12 and above, there's a big need for children to have an easy-to-take oral medicine, so they're working on that with a formulation that might be even easier to swallow.

We try to see our patients once or twice a year at minimum, even if they're doing well, to make sure their medicine is working and they're getting refills and they're not having side effects. When we make a change with any medicine, whether that's the acute medicines or the prophylactic medicines, I like to follow up with them sooner. I like to see people two to three months after we've made a change to troubleshoot any issues. Obviously, if the first attack goes poorly for some reason, then I want to know that sooner, but we do need to make sure this is working as expected and we're not seeing any unexpected problems.

We don't prescribe it for kids under 12. We don't have that data yet. But those studies are ongoing, and so far, it looks quite promising. We don't have any pregnancy or breastfeeding data, so we still steer back to C1 inhibitor concentrates during pregnancy because they have been around longer and have the most pregnancy safety data. So I wouldn't be giving Ekterly to women who were pregnant or breastfeeding. Because this is a pill, there are some drug interactions to consider, so we have to review people's medication lists. There are some instances where you have to adjust the dose or avoid use with certain other medications.

With rare medical conditions, cost of new medicines is always an issue. So Ekterly is fairly costly as medications go because it's a treatment for a relatively small group of people. That's true of all the HAE medicines; there's nothing different about this medication, cost-wise, compared to the others that are indicated for HAE. With any of these higher-cost medicines, there's always a lot of paperwork to fill out to get insurance coverage and authorization. But generally speaking, we've been able to do that for people. And most plans will eventually cover it if we provide the documentation and the rationale and the need. It does take time and effort, but for the most part, we've been successful in making sure that people have access to it.

A big question we ask people is: How successful has your current treatment been? Our patients all have at least one on-demand medication. We want to know: Are they able to use it quickly? Are they tolerating it well? Are they having any side effect concerns? And, of course, is it working fast enough for them? And if the answer is yes, then there might not be a huge need to change to a newer medicine. However, what we hear a lot is, "It's hard to keep my medicine with me or to store it. It's hard to give it. I'm afraid because it's painful. I'm anxious about whether I can do it or not when it comes time." That's the time to be thinking about trying an oral option. 

The theme in HAE in general has been that we keep making progress slowly but surely. Not only to make the treatments effective and safer, but also less burdensome. This is a lifelong condition at the moment. And so whatever medicine people are using, they're going to have to keep using it repeatedly. Burden of treatment is a real thing; it wears on you. We want to make the treatment as easy and as tolerable as we can.

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