By Donald S. Levy, MD, as told to Rachel Reiff Ellis
Donald S. Levy, MD, is an allergist and immunologist at UCI Health in Irvine, California. The information here represents his knowledge and experience as a medical professional.
Ecallantide (Kalbitor) is a drug that was FDA-approved in 2009 to treat acute attacks of hereditary angioedema (HAE). Although it is not frequently used today, it was the first drug of its class: the kallikrein inhibitors. Kallikrein inhibitors help stop attacks by blocking kallikrein, a substance that sets off a chain reaction that leads to the formation of bradykinin, which causes the hallmark swelling in HAE. This swelling can be disfiguring, painful, and sometimes life-threatening.
In the decades since Kalbitor’s approval, several other kallikrein inhibitor drugs have come on the market with easier modes of administration. Doctors are much more likely to prescribe these newer, more convenient options today than Kalbitor. However Kalbitor remains an effective HAE treatment option.
We spoke to Donald S. Levy, MD, an allergist and immunologist at UCI Health in Irvine, California, about how Kalbitor works and what else you need to know about this treatment.
Who typically benefits from this treatment?
Kalbitor is by and large an obsolete drug, but there are a few people who still use it. In theory, some people might do better on Kalbitor — perhaps those who have a type of HAE called “HAE with normal C1-inhibitor,” for example, which is set apart from HAE types I and II. And there are probably people who have been on Kalbitor and liked it since 2009 and would rather use that than newer options. But the majority of people with HAE aren't going to be using this drug. It's too clunky and cumbersome. There are other drugs that work with similar efficacy that are self-administered, so those are better options for most people.
What sets it apart from other treatments?
When Kalbitor came out in 2009, the previous FDA-approved long-term prophylaxis was only about 50%-60% effective. So not only was it a game-changing treatment because it was effective, it was also the first injectable. The FDA approved another C1 inhibitor replacement treatment, Berinert, in October of that same year, but it was an IV infusion. With Kalbitor, you could just get a shot, which was a lot easier to take than an IV.
Is this treatment generally considered safe?
As with any injectable drug, you may have a reaction at the injection site such as swelling, itching, redness, rash, or bruising. It also comes with a risk of severe allergic reactions, or anaphylaxis. Because of that risk, you aren’t supposed to inject it unless there's a healthcare professional nearby. You have to drive to the doctor's office, go to the emergency room or urgent care, or have someone come to your house to observe you after the injection.
How do you take it, and will people need any regular tests or checkups?
Kalbitor is a subcutaneous injection, which means it’s a shot you get just under your skin. A typical dose is three injections that equal 3 milliliters in your thigh, abdomen, or upper arm. All HAE patients have to come in for checkups on a somewhat regular basis, which these days might be twice a year because most people are really stable now.
Is there anyone who shouldn’t take it?
You shouldn’t take it if you have an anaphylactic response (a life-threatening allergic reaction) to a dose, which unfortunately you would only find out the hard way. If you’re pregnant, plan to get pregnant, or are breastfeeding, talk to your doctor — we don’t know how Kalbitor affects a fetus or breast milk. It’s only approved for people 12 years old and older.
How much does it cost? Will insurance cover it, or are there options for financial assistance?
Kalbitor costs about $17,400 per dose, but your insurance may cover some or all of that. Takeda Pharmaceuticals, the company that makes it, also offers a patient support program that offers financial assistance.
What are you excited about in the upcoming HAE treatment landscape?
In the beginning when there were no medicines for HAE, we worried about the burden of the disease. Now, we worry about the burden of therapy. Having to take a painful shot and having to have a medical professional there, there's a lot of burden with that. Kalbitor helped with the first worry, and now we’ve moved on to tackling the second. Today we have an oral on-demand medication with another oral on-demand on the horizon. We also have medications — even oral ones — to treat kids down to age 2 now.
Oral medications mean less hesitation to take medication. And there's going to be a newer oral medication coming out soon for prophylaxis that probably works a little bit better than the current one. In the next year, there should also be an approval of a CRISPR gene therapy that can do a one-time block of kallikrein in the liver. That means a one-time dose to treat HAE. It's a great time because we have lots of options. It's all about giving people a lot of options to be able to make a good choice, and that's the beauty of the HAE treatment landscape right now.
