Treatment may help keep HAE attacks away for years, study finds

Treatment with Andembry (garadacimab) may help prevent recurrent hereditary angioedema (HAE) attacks for years, with longer attack-free periods linked to better quality of life, according to a study based on statistical predictions.

The study, “Garadacimab in Hereditary Angioedema: Modeling Suggests Sustained Improvements in Attack-Free Probability and Quality of Life Over 5  Years,” was published in Clinical and Translational Science by an international team of researchers. It was funded by CSL Behring, which markets Andembry.

In HAE, high levels of the signaling molecule bradykinin cause blood vessels to dilate and leak fluid into surrounding tissues, causing sudden swelling under the skin in areas such as the face, throat, arms, and legs. These attacks can be life-threatening when the swelling around the throat presses against the airway.

Andembry is approved for the routine prevention of HAE attacks in adults and adolescents aged 12 and older. It works by blocking factor XIIa (FXIIa), a protein that triggers bradykinin production. By blocking FXIIa, Andembry reduces bradykinin levels, which helps limit swelling and ease angioedema symptoms.

The researchers developed a statistical model based on data from two completed Phase 3 clinical trials. The team wanted to predict how well long-term treatment with Andembry could prevent recurrent attacks by estimating the likelihood of remaining free from attacks over several years. They also estimated the effects of longer attack-free periods on health-related quality of life.

Recommended Reading

Oct. 15, 2026 Columns by Hollie Amadio

I encourage patients to self-advocate, but then I couldn’t do it myself

Model predicts prolonged treatment response

The model involved 128 patients with a median age of 42 who received Andembry as part of VANGUARD (NCT04656418) and its open-label extension (NCT04739059). Before treatment, patients experienced an average of 3.16 attacks per month. One month after starting treatment, the average went down to fewer than 0.3 attacks per month and continued to decrease over time.

The model closely matched the clinical data, suggesting it could reliably estimate patients’ treatment response. “These findings suggest that [Andembry] can enable prolonged periods without attacks, supporting a normalized quality of life for patients,” the researchers wrote. However, predictions beyond the period directly observed in the clinical trials are estimates, they noted.

Among patients who remained free of attacks during the first month of treatment, the model predicted a 60% probability of HAE remaining under control for 25 months (just over two years) and a 49% probability for up to five years. The model also predicted that the likelihood of having no attacks during individual six-month periods would increase with continued treatment.

“This decline in cumulative probability reflects the increasingly stringent requirement to remain continuously attack-free over a longer period and does not indicate waning efficacy; indeed, predicted attack-free probabilities within discrete [six]-month windows increased over time,” the researchers wrote. For example, for patients who maintained an initial six-month attack-free period, the predicted likelihood of remaining so reached 96% during months 31–36.

Quality of life was assessed using the Angioedema Quality of Life questionnaire, which measures how sudden swelling affects a patient’s daily activities and well-being. Quality of life improved as patients’ attack-free periods became longer. Those who remained attack-free for more than six months had average questionnaire scores below 20. In this questionnaire, lower scores indicate better quality of life.

The improvements were particularly noticeable in nutrition and physical functioning, which reflect how well people can eat, carry out daily activities, and manage physical tasks. Those who remained attack-free for at least 18 months (about 1.5 years) showed improvements across all measured quality-of-life areas.

The relationship between the duration of attack-free periods and quality of life was statistically significant, suggesting that the model may help doctors discuss long-term treatment.

“Model-based predictions can assist with individualized treatment decisions and provide reassurance about the potential for long-term attack prevention, while also providing evidence for expanding treatment access,” the researchers wrote.