Garadacimab demonstrates positive results in phase 3b trial for pediatric HAE prophylaxis

CSL reported positive top-line results from an open-label phase 3b study of garadacimab-gxii (Andembry) for prevention of hereditary angioedema (HAE) attacks in children aged 2 to 11 years. The company plans to seek an expanded pediatric indication.¹

“The top-line results support our plans to seek an expanded pediatric indication for ANDEMBRY in children aged 2 to 11 years,” Bill Mezzanotte, MD, executive vice president and head of research and development at CSL, said in the company announcement.¹

Garadacimab is currently indicated for HAE prophylaxis in patients aged 12 years or older and is approved in more than 40 countries, according to CSL.¹ The pediatric findings could extend a once-monthly or once-every-2-months preventive option to younger children, among whom treatment decisions may be complicated by limited age-specific evidence and the practical burden of repeated administration.

The multicenter study enrolled 22 children with HAE and followed them through a 12-month treatment period. Sixteen participants aged 6 to 11 years received garadacimab 100 mg subcutaneously once monthly. Six children aged 2 to 5 years received the same dose every 2 months.¹

CSL reported that most participants remained attack-free and that treatment responses were observed across the study population. However, the announcement did not provide the proportion of attack-free patients, baseline attack rates, changes in attack frequency, use of rescue medication, confidence intervals, or results stratified by age group.

The company characterized safety and tolerability as consistent with previous studies but did not report pediatric adverse-event counts, treatment discontinuations, or serious adverse events. In the current prescribing information for patients aged 12 years or older, common adverse reactions include injection-site reactions, abdominal pain, and nasopharyngitis.²

HAE is a rare genetic disorder, estimated by CSL to affect approximately 1 in 10,000 to 1 in 50,000 people.¹ Deficient or dysfunctional C1 esterase inhibitor can permit excessive activity in the kallikrein-kinin pathway, leading to bradykinin-mediated edema. Attacks may involve the extremities, face, gastrointestinal tract, or larynx. Laryngeal involvement can obstruct the airway and may be fatal without prompt treatment.

Management therefore includes access to on-demand treatment for acute episodes and consideration of long-term prophylaxis based on disease burden and individual circumstances.

Garadacimab is a monoclonal antibody directed against activated factor XII, or factor XIIa. By inhibiting factor XIIa near the beginning of the contact-system cascade, the drug is intended to reduce downstream bradykinin generation and prevent swelling attacks.¹ It is administered subcutaneously by a patient or trained caregiver under the current prescribing instructions.²

CSL said it plans to begin regulatory submissions during the first half of its fiscal year. Full findings are expected to be presented at a scientific congress and submitted to a peer-reviewed journal.

References

1. CSL. CSL reports positive top-line phase 3b results supporting planned expanded pediatric filing for Andembry (garadacimab-gxii) in children with hereditary angioedema. PR Newswire. July 27, 2026. Accessed July 27, 2026. https://www.prnewswire.com/news-releases/csl-reports-positive-top-line-phase-3b-results-supporting-planned-expanded-pediatric-filing-for-andembry-garadacimab-gxii-in-children-with-hereditary-angioedema-hae-302833811.html

2. CSL Behring. Andembry (garadacimab-gxii) prescribing information. https://edge.prnewswire.com/c/link/?t=0&l=en&o=4738068-1&h=2933321169&u=https%3A%2F%2Flabeling.cslbehring.com%2FPI%2FUS%2FAndembry%2FEN%2FAndembry-Prescribing-Information.pdf&a=prescribing+information