Rapid Treatment of Hereditary Angioedema Attacks at the Onset of Prodromal Symptoms Decreases Morbidity and Mortality

Washington, D.C. — 15 March 2009

The importance of recognizing prodromal symptoms and treating acute attacks of hereditary angioedema (HAE) at the onset of these symptoms was highlighted in a survey presented today at the 2009 American Academy of Allergy, Asthma & Immunology (AAAAI) Annual Meeting. While symptoms of acute HAE attacks include episodes of edema or swelling in the hands and feet, the face, the abdomen, and/or the larynx, prodromal symptoms, which occur before an attack, are often non-specific and highly-variable, according to study findings. Treatment at the onset of these early symptoms can decrease morbidity and mortality associated with this rare and serious genetic disorder.

The prodromal symptoms companion survey, administered in parallel with the ongoing, prospective, open label International Multi-center Prospective Angioedema C1-Inhibitor Trial (I.M.P.A.C.T. 2), was designed to assess prodromal symptoms at the time of treatment of HAE attacks. Twenty-seven different patients were surveyed, representing 273 attacks, two-thirds of which were treated with C1 esterase inhibitor concentrate (C1-INH) at the time of their attack. The most commonly reported prodromal symptoms across all types of attacks were fatigue (27.83%), nausea (19.41%) and flu-like feelings (13.19%). Other prodromal symptoms included bowel movement change (7.33%), rumbling (5.86%), urticaria-like skin eruptions (6.54%), non-itchy rash (5.38%) and tingling (3.30%).

"To date there has been very little research into prodromal symptoms associated with HAE attacks," said Timothy J. Craig, D.O., Professor of Medicine and Pediatrics at Penn State University in Hershey, PA., and one of the study’s investigators. "This survey underscores how important it is for patients to recognize the early symptoms of an HAE attack, as rapid treatment and resolution at this stage can reduce the impact the disease has on their quality of life."

HAE is a genetic disorder affecting approximately 6,000 to 10,000 Americans and is caused by a deficiency of C1-INH, which is inherited in an autosomal dominant manner. Patients who have abdominal attacks can experience episodes of severe pain, diarrhea, nausea, and vomiting caused by swelling of the intestinal wall. Attacks that involve the face and larynx can result in airway closure, asphyxiation, and, if untreated, death. Diagnosis of HAE requires a blood test to confirm low or abnormal levels of C1-INH.

About I.M.P.A.C.T. 2
Findings of I.M.P.A.C.T. 2 were based on treatment with 20 U/kg bodyweight of C1-INH in 640 episodes of HAE attacks at any body location in 57 patients. The main study end-points were: time to onset of symptom relief; complete resolution of all symptoms, and safety.

The median time to the onset of symptom relief was 16 minutes for laryngeal attacks, 23 minutes for abdominal attacks, 28 minutes for facial attacks and 31 minutes for peripheral attacks, such as attacks in the hands and feet. The median times to complete resolution of all symptoms were reported as early as 8 hours for laryngeal attacks, 11 hours for abdominal, 24 hours for facial and 25 hours for peripheral attacks. No drug-related serious adverse events have been reported to date, nor were any rebound effects observed following C1-INH administration.

Currently, there are no approved therapies for acute attacks of HAE in North America. CSL Behring manufactures and sells C1-INH concentrate in Germany, Austria, Switzerland, and several other countries.

About CSL Behring
CSL Behring is a global leader in the plasma protein biotherapeutics industry. Passionate about improving the quality of patients' lives, CSL Behring manufactures and markets a range of safe and effective plasma-derived and recombinant products and related services. The company's therapies are used in the treatment of immune deficiency disorders, hemophilia, von Willebrand disease, other bleeding disorders and inherited emphysema. Other products are used for the prevention of hemolytic diseases in the newborn, in cardiac surgery, organ transplantation and in the treatment of burns. The company also operates one of the world's largest plasma collection networks, ZLB Plasma. CSL Behring is a subsidiary of CSL Limited, a biopharmaceutical company with headquarters in Melbourne, Australia. For more information, visit

On-Site Contacts:
Sheila A. Burke, Director, Communications & Public Relations
Worldwide Commercial Operations
CSL Behring
484-919-2618 (c)
610-878-4209 (o)

Jennifer McGuire
MCS Healthcare Public Relations
973-479-9845 (c)
908-234-9900 (o)

Jeff Hoyak
MCS Healthcare Public Relations
908-884-6753 (c)
908-234-9900 (o)

LinkedIn Twitter Facebook Google+