June 18, 2025 — The FDA has approved a first-of-its-kind treatment for a rare genetic condition that causes frequent, unpredictable, and painful swelling in different parts of the body.
The drug, known as garadacimab but sold under the name Andembry, is used to prevent attacks of hereditary angioedema (HAE) in adults and children 12 and older. It is the only preventive treatment with a monthly dosing schedule for this potentially life-threatening condition that affects about 1 in 50,000 people.
HAE happens when a faulty gene leads to low levels or poor function of a protein called C1 inhibitor, which normally helps keep inflammation in check. Without enough of it, people can have swelling in their face, throat, belly, or limbs. Swelling in the abdomen can cause pain, nausea, vomiting, or diarrhea. If it affects the throat or face, it can block the airway and become life-threatening if not treated.
CSL Behring, the maker of Andembry, said the approval was based on a clinical trial involving patients aged 12 and older with HAE. For six months, they received either Andembry (a 400-milligram starting dose followed by 200 milligrams monthly) or a placebo. Andembry helped 62% of people stay attack-free during the treatment period. For many, HAE attacks dropped by more than 99%, and on average, they decreased by about 89% compared to a placebo. It also lowered the need for emergency treatment by about 99% and reduced moderate to severe attacks by around 90% on average.
An interim report from an ongoing study showed that Andembry is safe for long-term use and continues to reduce HAE attacks, according to the company's press release.
"We now have a new option to manage this condition through a new target, as it allows us for the first time to inhibit the top of the HAE cascade by targeting factor XIIa," stated Tim Craig, DO, professor of medicine, pediatrics and biomedical sciences at Penn State University, highlighting the unmet needs in HAE treatment. In other words, by targeting factor XIIa — a protein that starts the swelling process in people with HAE — the new treatment stops the swelling process at the beginning, rather than after it has begun. It’s a more direct way to prevent attacks before they happen.
The new treatment is given once a month as a simple under-the-skin injection using an autoinjector that patients or caregivers can learn to use.
Common side effects include sore throat with runny or stuffy nose, abdominal pain, and injection site reactions such as bruising, redness, swelling, itching, and mild rash. CSL Behring plans to make Andembry available before the end of June.